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<!DOCTYPE html>
<html lang="en" class="Internet-Draft">
<head>
<meta charset="utf-8">
<meta content="Common,Latin" name="scripts">
<meta content="initial-scale=1.0" name="viewport">
<title>Execution Context Tokens for Distributed Agentic Workflows</title>
<meta content="Christian Nennemann" name="author">
<meta content="
This document defines Execution Context Tokens (ECTs), a JWT-based
extension to the WIMSE architecture that records task execution
across distributed agentic workflows. Each ECT is a signed record
of a single task, linked to predecessor tasks through a directed
acyclic graph (DAG). ECTs reuse the WIMSE signing model and are
transported in a new Execution-Context HTTP header field alongside
existing WIMSE identity headers.
" name="description">
<meta content="xml2rfc 3.31.0" name="generator">
<meta content="execution context" name="keyword">
<meta content="workload identity" name="keyword">
<meta content="agentic workflows" name="keyword">
<meta content="audit trail" name="keyword">
<meta content="draft-nennemann-wimse-ect-00" name="ietf.draft">
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xml2rfc 3.31.0
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<link href="#copyright" rel="license">
<style type="text/css">/*
NOTE: Changes at the bottom of this file overrides some earlier settings.
Once the style has stabilized and has been adopted as an official RFC style,
this can be consolidated so that style settings occur only in one place, but
for now the contents of this file consists first of the initial CSS work as
provided to the RFC Formatter (xml2rfc) work, followed by itemized and
commented changes found necessary during the development of the v3
formatters.
*/
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@import url('https://static.ietf.org/fonts/noto-serif/import.css'); /* Serif (print) */
@import url('https://static.ietf.org/fonts/roboto-mono/import.css'); /* Monospace */
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*/
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/* Fix PDF info block run off issue */
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/* make the index two-column on all but the smallest screens */
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/* Changes introduced to fix issues found during implementation */
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/* Provide table alignment support. We can't use the alignX classes above
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table.left {
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/* Give the table caption label the same styling as the figcaption */
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/* avoid overwriting the top border line with the ToC header */
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/* Float artwork pilcrow to the right */
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/* Make pilcrows on dd visible */
@media screen {
dd:hover > a.pilcrow {
visibility: visible;
}
}
/* Make the placement of figcaption match that of a table's caption
by removing the figure's added bottom margin */
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.alignRight {
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/* In print, the pilcrow won't show on hover, so prevent it from taking up space,
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/* Styling for the external metadata */
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/* Styling for title RFC Number */
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/* Make .olPercent look the same as <ol><li> */
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/* Give aside some styling to set it apart */
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aside > ul,
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aside > p {
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<table class="ears">
<thead><tr>
<td class="left">Internet-Draft</td>
<td class="center">WIMSE Execution Context</td>
<td class="right">February 2026</td>
</tr></thead>
<tfoot><tr>
<td class="left">Nennemann</td>
<td class="center">Expires 29 August 2026</td>
<td class="right">[Page]</td>
</tr></tfoot>
</table>
<div id="external-metadata" class="document-information"></div>
<div id="internal-metadata" class="document-information">
<dl id="identifiers">
<dt class="label-workgroup">Workgroup:</dt>
<dd class="workgroup">WIMSE</dd>
<dt class="label-internet-draft">Internet-Draft:</dt>
<dd class="internet-draft">draft-nennemann-wimse-ect-00</dd>
<dt class="label-published">Published:</dt>
<dd class="published">
<time datetime="2026-02-25" class="published">25 February 2026</time>
</dd>
<dt class="label-intended-status">Intended Status:</dt>
<dd class="intended-status">Standards Track</dd>
<dt class="label-expires">Expires:</dt>
<dd class="expires"><time datetime="2026-08-29">29 August 2026</time></dd>
<dt class="label-authors">Author:</dt>
<dd class="authors">
<div class="author">
<div class="author-name">C. Nennemann</div>
<div class="org">Independent Researcher</div>
</div>
</dd>
</dl>
</div>
<h1 id="title">Execution Context Tokens for Distributed Agentic Workflows</h1>
<section id="section-abstract">
<h2 id="abstract"><a href="#abstract" class="selfRef">Abstract</a></h2>
<p id="section-abstract-1">This document defines Execution Context Tokens (ECTs), a JWT-based
extension to the WIMSE architecture that records task execution
across distributed agentic workflows. Each ECT is a signed record
of a single task, linked to predecessor tasks through a directed
acyclic graph (DAG). ECTs reuse the WIMSE signing model and are
transported in a new Execution-Context HTTP header field alongside
existing WIMSE identity headers.<a href="#section-abstract-1" class="pilcrow"></a></p>
</section>
<div id="status-of-memo">
<section id="section-boilerplate.1">
<h2 id="name-status-of-this-memo">
<a href="#name-status-of-this-memo" class="section-name selfRef">Status of This Memo</a>
</h2>
<p id="section-boilerplate.1-1">
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.<a href="#section-boilerplate.1-1" class="pilcrow"></a></p>
<p id="section-boilerplate.1-2">
Internet-Drafts are working documents of the Internet Engineering Task
Force (IETF). Note that other groups may also distribute working
documents as Internet-Drafts. The list of current Internet-Drafts is
at <span><a href="https://datatracker.ietf.org/drafts/current/">https://datatracker.ietf.org/drafts/current/</a></span>.<a href="#section-boilerplate.1-2" class="pilcrow"></a></p>
<p id="section-boilerplate.1-3">
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."<a href="#section-boilerplate.1-3" class="pilcrow"></a></p>
<p id="section-boilerplate.1-4">
This Internet-Draft will expire on 29 August 2026.<a href="#section-boilerplate.1-4" class="pilcrow"></a></p>
</section>
</div>
<div id="copyright">
<section id="section-boilerplate.2">
<h2 id="name-copyright-notice">
<a href="#name-copyright-notice" class="section-name selfRef">Copyright Notice</a>
</h2>
<p id="section-boilerplate.2-1">
Copyright (c) 2026 IETF Trust and the persons identified as the
document authors. All rights reserved.<a href="#section-boilerplate.2-1" class="pilcrow"></a></p>
<p id="section-boilerplate.2-2">
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(<span><a href="https://trustee.ietf.org/license-info">https://trustee.ietf.org/license-info</a></span>) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with
respect to this document. Code Components extracted from this
document must include Revised BSD License text as described in
Section 4.e of the Trust Legal Provisions and are provided without
warranty as described in the Revised BSD License.<a href="#section-boilerplate.2-2" class="pilcrow"></a></p>
</section>
</div>
<div id="toc">
<section id="section-toc.1">
<a href="#" onclick="scroll(0,0)" class="toplink"></a><h2 id="name-table-of-contents">
<a href="#name-table-of-contents" class="section-name selfRef">Table of Contents</a>
</h2>
<nav class="toc"><ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.1">
<p id="section-toc.1-1.1.1" class="keepWithNext"><a href="#section-1" class="auto internal xref">1</a>.  <a href="#name-introduction" class="internal xref">Introduction</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.1.2.1">
<p id="section-toc.1-1.1.2.1.1" class="keepWithNext"><a href="#section-1.1" class="auto internal xref">1.1</a>.  <a href="#name-scope-and-applicability" class="internal xref">Scope and Applicability</a></p>
</li>
</ul>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.2">
<p id="section-toc.1-1.2.1" class="keepWithNext"><a href="#section-2" class="auto internal xref">2</a>.  <a href="#name-conventions-and-definitions" class="internal xref">Conventions and Definitions</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.3">
<p id="section-toc.1-1.3.1"><a href="#section-3" class="auto internal xref">3</a>.  <a href="#name-execution-context-token-for" class="internal xref">Execution Context Token Format</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.3.2.1">
<p id="section-toc.1-1.3.2.1.1"><a href="#section-3.1" class="auto internal xref">3.1</a>.  <a href="#name-jose-header" class="internal xref">JOSE Header</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.3.2.2">
<p id="section-toc.1-1.3.2.2.1"><a href="#section-3.2" class="auto internal xref">3.2</a>.  <a href="#name-jwt-claims" class="internal xref">JWT Claims</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.3.2.2.2.1">
<p id="section-toc.1-1.3.2.2.2.1.1"><a href="#section-3.2.1" class="auto internal xref">3.2.1</a>.  <a href="#name-standard-jwt-claims" class="internal xref">Standard JWT Claims</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.3.2.2.2.2">
<p id="section-toc.1-1.3.2.2.2.2.1"><a href="#section-3.2.2" class="auto internal xref">3.2.2</a>.  <a href="#name-execution-context" class="internal xref">Execution Context</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.3.2.2.2.3">
<p id="section-toc.1-1.3.2.2.2.3.1"><a href="#section-3.2.3" class="auto internal xref">3.2.3</a>.  <a href="#name-data-integrity" class="internal xref">Data Integrity</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.3.2.2.2.4">
<p id="section-toc.1-1.3.2.2.2.4.1"><a href="#section-3.2.4" class="auto internal xref">3.2.4</a>.  <a href="#name-extensions" class="internal xref">Extensions</a></p>
</li>
</ul>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.3.2.3">
<p id="section-toc.1-1.3.2.3.1"><a href="#section-3.3" class="auto internal xref">3.3</a>.  <a href="#name-complete-ect-example" class="internal xref">Complete ECT Example</a></p>
</li>
</ul>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.4">
<p id="section-toc.1-1.4.1"><a href="#section-4" class="auto internal xref">4</a>.  <a href="#name-http-header-transport" class="internal xref">HTTP Header Transport</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.4.2.1">
<p id="section-toc.1-1.4.2.1.1"><a href="#section-4.1" class="auto internal xref">4.1</a>.  <a href="#name-execution-context-header-fi" class="internal xref">Execution-Context Header Field</a></p>
</li>
</ul>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.5">
<p id="section-toc.1-1.5.1"><a href="#section-5" class="auto internal xref">5</a>.  <a href="#name-dag-validation" class="internal xref">DAG Validation</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.6">
<p id="section-toc.1-1.6.1"><a href="#section-6" class="auto internal xref">6</a>.  <a href="#name-signature-and-token-verific" class="internal xref">Signature and Token Verification</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.6.2.1">
<p id="section-toc.1-1.6.2.1.1"><a href="#section-6.1" class="auto internal xref">6.1</a>.  <a href="#name-verification-procedure" class="internal xref">Verification Procedure</a></p>
</li>
</ul>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.7">
<p id="section-toc.1-1.7.1"><a href="#section-7" class="auto internal xref">7</a>.  <a href="#name-audit-ledger-interface" class="internal xref">Audit Ledger Interface</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8">
<p id="section-toc.1-1.8.1"><a href="#section-8" class="auto internal xref">8</a>.  <a href="#name-security-considerations" class="internal xref">Security Considerations</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8.2.1">
<p id="section-toc.1-1.8.2.1.1"><a href="#section-8.1" class="auto internal xref">8.1</a>.  <a href="#name-threat-model" class="internal xref">Threat Model</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8.2.2">
<p id="section-toc.1-1.8.2.2.1"><a href="#section-8.2" class="auto internal xref">8.2</a>.  <a href="#name-self-assertion-limitation" class="internal xref">Self-Assertion Limitation</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8.2.3">
<p id="section-toc.1-1.8.2.3.1"><a href="#section-8.3" class="auto internal xref">8.3</a>.  <a href="#name-signature-verification" class="internal xref">Signature Verification</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8.2.4">
<p id="section-toc.1-1.8.2.4.1"><a href="#section-8.4" class="auto internal xref">8.4</a>.  <a href="#name-replay-attack-prevention" class="internal xref">Replay Attack Prevention</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8.2.5">
<p id="section-toc.1-1.8.2.5.1"><a href="#section-8.5" class="auto internal xref">8.5</a>.  <a href="#name-man-in-the-middle-protectio" class="internal xref">Man-in-the-Middle Protection</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8.2.6">
<p id="section-toc.1-1.8.2.6.1"><a href="#section-8.6" class="auto internal xref">8.6</a>.  <a href="#name-key-compromise" class="internal xref">Key Compromise</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8.2.7">
<p id="section-toc.1-1.8.2.7.1"><a href="#section-8.7" class="auto internal xref">8.7</a>.  <a href="#name-collusion-and-dag-integrity" class="internal xref">Collusion and DAG Integrity</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8.2.8">
<p id="section-toc.1-1.8.2.8.1"><a href="#section-8.8" class="auto internal xref">8.8</a>.  <a href="#name-privilege-escalation-via-ec" class="internal xref">Privilege Escalation via ECTs</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8.2.9">
<p id="section-toc.1-1.8.2.9.1"><a href="#section-8.9" class="auto internal xref">8.9</a>.  <a href="#name-denial-of-service" class="internal xref">Denial of Service</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8.2.10">
<p id="section-toc.1-1.8.2.10.1"><a href="#section-8.10" class="auto internal xref">8.10</a>. <a href="#name-timestamp-accuracy" class="internal xref">Timestamp Accuracy</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.8.2.11">
<p id="section-toc.1-1.8.2.11.1"><a href="#section-8.11" class="auto internal xref">8.11</a>. <a href="#name-ect-size-constraints" class="internal xref">ECT Size Constraints</a></p>
</li>
</ul>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.9">
<p id="section-toc.1-1.9.1"><a href="#section-9" class="auto internal xref">9</a>.  <a href="#name-privacy-considerations" class="internal xref">Privacy Considerations</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.9.2.1">
<p id="section-toc.1-1.9.2.1.1"><a href="#section-9.1" class="auto internal xref">9.1</a>.  <a href="#name-data-exposure-in-ects" class="internal xref">Data Exposure in ECTs</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.9.2.2">
<p id="section-toc.1-1.9.2.2.1"><a href="#section-9.2" class="auto internal xref">9.2</a>.  <a href="#name-data-minimization" class="internal xref">Data Minimization</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.9.2.3">
<p id="section-toc.1-1.9.2.3.1"><a href="#section-9.3" class="auto internal xref">9.3</a>.  <a href="#name-storage-and-access-control" class="internal xref">Storage and Access Control</a></p>
</li>
</ul>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.10">
<p id="section-toc.1-1.10.1"><a href="#section-10" class="auto internal xref">10</a>. <a href="#name-iana-considerations" class="internal xref">IANA Considerations</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.10.2.1">
<p id="section-toc.1-1.10.2.1.1"><a href="#section-10.1" class="auto internal xref">10.1</a>.  <a href="#name-media-type-registration" class="internal xref">Media Type Registration</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.10.2.2">
<p id="section-toc.1-1.10.2.2.1"><a href="#section-10.2" class="auto internal xref">10.2</a>.  <a href="#name-http-header-field-registrat" class="internal xref">HTTP Header Field Registration</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.10.2.3">
<p id="section-toc.1-1.10.2.3.1"><a href="#section-10.3" class="auto internal xref">10.3</a>.  <a href="#name-jwt-claims-registration" class="internal xref">JWT Claims Registration</a></p>
</li>
</ul>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.11">
<p id="section-toc.1-1.11.1"><a href="#section-11" class="auto internal xref">11</a>. <a href="#name-references" class="internal xref">References</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.11.2.1">
<p id="section-toc.1-1.11.2.1.1"><a href="#section-11.1" class="auto internal xref">11.1</a>.  <a href="#name-normative-references" class="internal xref">Normative References</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.11.2.2">
<p id="section-toc.1-1.11.2.2.1"><a href="#section-11.2" class="auto internal xref">11.2</a>.  <a href="#name-informative-references" class="internal xref">Informative References</a></p>
</li>
</ul>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.12">
<p id="section-toc.1-1.12.1"><a href="#appendix-A" class="auto internal xref"></a><a href="#name-use-cases" class="internal xref">Use Cases</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.12.2.1">
<p id="section-toc.1-1.12.2.1.1"><a href="#appendix-A.1" class="auto internal xref"></a><a href="#name-cross-organization-financia" class="internal xref">Cross-Organization Financial Trading</a></p>
</li>
</ul>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.13">
<p id="section-toc.1-1.13.1"><a href="#appendix-B" class="auto internal xref"></a><a href="#name-related-work" class="internal xref">Related Work</a></p>
<ul class="compact toc ulBare ulEmpty">
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.13.2.1">
<p id="section-toc.1-1.13.2.1.1"><a href="#appendix-B.1" class="auto internal xref"></a><a href="#name-wimse-workload-identity" class="internal xref">WIMSE Workload Identity</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.13.2.2">
<p id="section-toc.1-1.13.2.2.1"><a href="#appendix-B.2" class="auto internal xref"></a><a href="#name-oauth-20-token-exchange-and" class="internal xref">OAuth 2.0 Token Exchange and the "act" Claim</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.13.2.3">
<p id="section-toc.1-1.13.2.3.1"><a href="#appendix-B.3" class="auto internal xref"></a><a href="#name-transaction-tokens" class="internal xref">Transaction Tokens</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.13.2.4">
<p id="section-toc.1-1.13.2.4.1"><a href="#appendix-B.4" class="auto internal xref"></a><a href="#name-distributed-tracing-opentel" class="internal xref">Distributed Tracing (OpenTelemetry)</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.13.2.5">
<p id="section-toc.1-1.13.2.5.1"><a href="#appendix-B.5" class="auto internal xref"></a><a href="#name-w3c-provenance-data-model-p" class="internal xref">W3C Provenance Data Model (PROV)</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.13.2.6">
<p id="section-toc.1-1.13.2.6.1"><a href="#appendix-B.6" class="auto internal xref"></a><a href="#name-scitt-supply-chain-integrit" class="internal xref">SCITT (Supply Chain Integrity, Transparency, and Trust)</a></p>
</li>
</ul>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.14">
<p id="section-toc.1-1.14.1"><a href="#appendix-C" class="auto internal xref"></a><a href="#name-acknowledgments" class="internal xref">Acknowledgments</a></p>
</li>
<li class="compact toc ulBare ulEmpty" id="section-toc.1-1.15">
<p id="section-toc.1-1.15.1"><a href="#appendix-D" class="auto internal xref"></a><a href="#name-authors-address" class="internal xref">Author's Address</a></p>
</li>
</ul>
</nav>
</section>
</div>
<div id="introduction">
<section id="section-1">
<h2 id="name-introduction">
<a href="#section-1" class="section-number selfRef">1. </a><a href="#name-introduction" class="section-name selfRef">Introduction</a>
</h2>
<p id="section-1-1">The WIMSE framework <span>[<a href="#I-D.ietf-wimse-arch" class="cite xref">I-D.ietf-wimse-arch</a>]</span> and its service-to-
service protocol <span>[<a href="#I-D.ietf-wimse-s2s-protocol" class="cite xref">I-D.ietf-wimse-s2s-protocol</a>]</span> authenticate
workloads across call chains but do not record what those
workloads actually did. This document defines Execution Context
Tokens (ECTs), a JWT-based extension that fills the gap between
workload identity and execution accountability. Each ECT is a
signed record of a single task, linked to predecessor tasks
through a directed acyclic graph (DAG).<a href="#section-1-1" class="pilcrow"></a></p>
<div id="scope-and-applicability">
<section id="section-1.1">
<h3 id="name-scope-and-applicability">
<a href="#section-1.1" class="section-number selfRef">1.1. </a><a href="#name-scope-and-applicability" class="section-name selfRef">Scope and Applicability</a>
</h3>
<p id="section-1.1-1">This document defines:<a href="#section-1.1-1" class="pilcrow"></a></p>
<ul class="normal">
<li class="normal" id="section-1.1-2.1">
<p id="section-1.1-2.1.1">The Execution Context Token (ECT) format (<a href="#ect-format" class="auto internal xref">Section 3</a>)<a href="#section-1.1-2.1.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-1.1-2.2">
<p id="section-1.1-2.2.1">DAG structure for task dependency ordering (<a href="#dag-validation" class="auto internal xref">Section 5</a>)<a href="#section-1.1-2.2.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-1.1-2.3">
<p id="section-1.1-2.3.1">An HTTP header for ECT transport (<a href="#http-header" class="auto internal xref">Section 4</a>)<a href="#section-1.1-2.3.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-1.1-2.4">
<p id="section-1.1-2.4.1">Audit ledger interface requirements (<a href="#ledger-interface" class="auto internal xref">Section 7</a>)<a href="#section-1.1-2.4.1" class="pilcrow"></a></p>
</li>
</ul>
<p id="section-1.1-3">The following are out of scope and are handled by WIMSE:<a href="#section-1.1-3" class="pilcrow"></a></p>
<ul class="normal">
<li class="normal" id="section-1.1-4.1">
<p id="section-1.1-4.1.1">Workload authentication and identity provisioning<a href="#section-1.1-4.1.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-1.1-4.2">
<p id="section-1.1-4.2.1">Key distribution and management<a href="#section-1.1-4.2.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-1.1-4.3">
<p id="section-1.1-4.3.1">Trust domain establishment and management<a href="#section-1.1-4.3.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-1.1-4.4">
<p id="section-1.1-4.4.1">Credential lifecycle management<a href="#section-1.1-4.4.1" class="pilcrow"></a></p>
</li>
</ul>
</section>
</div>
</section>
</div>
<div id="conventions-and-definitions">
<section id="section-2">
<h2 id="name-conventions-and-definitions">
<a href="#section-2" class="section-number selfRef">2. </a><a href="#name-conventions-and-definitions" class="section-name selfRef">Conventions and Definitions</a>
</h2>
<p id="section-2-1">The key words "<span class="bcp14">MUST</span>", "<span class="bcp14">MUST NOT</span>", "<span class="bcp14">REQUIRED</span>", "<span class="bcp14">SHALL</span>", "<span class="bcp14">SHALL NOT</span>", "<span class="bcp14">SHOULD</span>", "<span class="bcp14">SHOULD NOT</span>", "<span class="bcp14">RECOMMENDED</span>", "<span class="bcp14">NOT RECOMMENDED</span>",
"<span class="bcp14">MAY</span>", and "<span class="bcp14">OPTIONAL</span>" in this document are to be interpreted as
described in BCP 14 <span>[<a href="#RFC2119" class="cite xref">RFC2119</a>]</span> <span>[<a href="#RFC8174" class="cite xref">RFC8174</a>]</span> when, and only when, they
appear in all capitals, as shown here.<a href="#section-2-1" class="pilcrow"></a></p>
<p id="section-2-2">The following terms are used in this document:<a href="#section-2-2" class="pilcrow"></a></p>
<span class="break"></span><dl class="dlParallel" id="section-2-3">
<dt id="section-2-3.1">Agent:</dt>
<dd style="margin-left: 1.5em" id="section-2-3.2">
<p id="section-2-3.2.1">An autonomous workload, as defined by WIMSE
<span>[<a href="#I-D.ietf-wimse-arch" class="cite xref">I-D.ietf-wimse-arch</a>]</span>, that executes tasks within a workflow.<a href="#section-2-3.2.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-2-3.3">Task:</dt>
<dd style="margin-left: 1.5em" id="section-2-3.4">
<p id="section-2-3.4.1">A discrete unit of agent work that consumes inputs and produces
outputs.<a href="#section-2-3.4.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-2-3.5">Directed Acyclic Graph (DAG):</dt>
<dd style="margin-left: 1.5em" id="section-2-3.6">
<p id="section-2-3.6.1">A graph structure representing task dependency ordering where
edges are directed and no cycles exist.<a href="#section-2-3.6.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-2-3.7">Execution Context Token (ECT):</dt>
<dd style="margin-left: 1.5em" id="section-2-3.8">
<p id="section-2-3.8.1">A JSON Web Token <span>[<a href="#RFC7519" class="cite xref">RFC7519</a>]</span> defined by this specification that
records task execution details.<a href="#section-2-3.8.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-2-3.9">Audit Ledger:</dt>
<dd style="margin-left: 1.5em" id="section-2-3.10">
<p id="section-2-3.10.1">An append-only, immutable log of all ECTs within a workflow or
set of workflows, used for audit and verification.<a href="#section-2-3.10.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-2-3.11">Workload Identity Token (WIT):</dt>
<dd style="margin-left: 1.5em" id="section-2-3.12">
<p id="section-2-3.12.1">A WIMSE credential proving a workload's identity within a trust
domain.<a href="#section-2-3.12.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-2-3.13">Workload Proof Token (WPT):</dt>
<dd style="margin-left: 1.5em" id="section-2-3.14">
<p id="section-2-3.14.1">A WIMSE proof-of-possession token used for request-level
authentication.<a href="#section-2-3.14.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-2-3.15">Trust Domain:</dt>
<dd style="margin-left: 1.5em" id="section-2-3.16">
<p id="section-2-3.16.1">A WIMSE concept representing an organizational boundary with a
shared identity issuer, corresponding to a SPIFFE <span>[<a href="#SPIFFE" class="cite xref">SPIFFE</a>]</span>
trust domain.<a href="#section-2-3.16.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
</dl>
</section>
</div>
<div id="ect-format">
<section id="section-3">
<h2 id="name-execution-context-token-for">
<a href="#section-3" class="section-number selfRef">3. </a><a href="#name-execution-context-token-for" class="section-name selfRef">Execution Context Token Format</a>
</h2>
<p id="section-3-1">An Execution Context Token is a JSON Web Token (JWT) <span>[<a href="#RFC7519" class="cite xref">RFC7519</a>]</span>
signed as a JSON Web Signature (JWS) <span>[<a href="#RFC7515" class="cite xref">RFC7515</a>]</span>. ECTs <span class="bcp14">MUST</span> use
JWS Compact Serialization (the base64url-encoded
<code>header.payload.signature</code> format) so that they can be carried in
a single HTTP header value.<a href="#section-3-1" class="pilcrow"></a></p>
<p id="section-3-2">ECTs reuse the WIMSE signing model. The ECT <span class="bcp14">MUST</span> be signed with
the same private key associated with the agent's WIT. The JOSE
header "kid" parameter <span class="bcp14">MUST</span> reference the public key identifier
from the agent's WIT, and the "alg" parameter <span class="bcp14">MUST</span> match the
algorithm used in the corresponding WIT. In WIMSE deployments,
the ECT "iss" claim <span class="bcp14">SHOULD</span> use the WIMSE workload identifier
format (a SPIFFE ID <span>[<a href="#SPIFFE" class="cite xref">SPIFFE</a>]</span>).<a href="#section-3-2" class="pilcrow"></a></p>
<div id="jose-header">
<section id="section-3.1">
<h3 id="name-jose-header">
<a href="#section-3.1" class="section-number selfRef">3.1. </a><a href="#name-jose-header" class="section-name selfRef">JOSE Header</a>
</h3>
<p id="section-3.1-1">The ECT JOSE header <span class="bcp14">MUST</span> contain the following parameters:<a href="#section-3.1-1" class="pilcrow"></a></p>
<span id="name-ect-jose-header-example"></span><div id="fig-header">
<figure id="figure-1">
<div class="lang-json sourcecode" id="section-3.1-2.1">
<pre>
{
"alg": "ES256",
"typ": "wimse-exec+jwt",
"kid": "agent-a-key-id-123"
}
</pre>
</div>
<figcaption><a href="#figure-1" class="selfRef">Figure 1</a>:
<a href="#name-ect-jose-header-example" class="selfRef">ECT JOSE Header Example</a>
</figcaption></figure>
</div>
<span class="break"></span><dl class="dlParallel" id="section-3.1-3">
<dt id="section-3.1-3.1">alg:</dt>
<dd style="margin-left: 1.5em" id="section-3.1-3.2">
<p id="section-3.1-3.2.1"><span class="bcp14">REQUIRED</span>. The digital signature algorithm used to sign the ECT.
<span class="bcp14">MUST</span> match the algorithm in the corresponding WIT.
Implementations <span class="bcp14">MUST</span> support ES256 <span>[<a href="#RFC7518" class="cite xref">RFC7518</a>]</span>. The "alg"
value <span class="bcp14">MUST NOT</span> be "none". Symmetric algorithms (e.g., HS256,
HS384, HS512) <span class="bcp14">MUST NOT</span> be used, as ECTs require asymmetric
signatures for non-repudiation.<a href="#section-3.1-3.2.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-3.1-3.3">typ:</dt>
<dd style="margin-left: 1.5em" id="section-3.1-3.4">
<p id="section-3.1-3.4.1"><span class="bcp14">REQUIRED</span>. <span class="bcp14">MUST</span> be set to "wimse-exec+jwt" to distinguish ECTs
from other JWT types, consistent with the WIMSE convention for
type parameter values.<a href="#section-3.1-3.4.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-3.1-3.5">kid:</dt>
<dd style="margin-left: 1.5em" id="section-3.1-3.6">
<p id="section-3.1-3.6.1"><span class="bcp14">REQUIRED</span>. The key identifier referencing the public key from
the agent's WIT <span>[<a href="#RFC7517" class="cite xref">RFC7517</a>]</span>. Used by verifiers to look up the
correct public key for signature verification.<a href="#section-3.1-3.6.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
</dl>
</section>
</div>
<div id="jwt-claims">
<section id="section-3.2">
<h3 id="name-jwt-claims">
<a href="#section-3.2" class="section-number selfRef">3.2. </a><a href="#name-jwt-claims" class="section-name selfRef">JWT Claims</a>
</h3>
<div id="standard-jwt-claims">
<section id="section-3.2.1">
<h4 id="name-standard-jwt-claims">
<a href="#section-3.2.1" class="section-number selfRef">3.2.1. </a><a href="#name-standard-jwt-claims" class="section-name selfRef">Standard JWT Claims</a>
</h4>
<p id="section-3.2.1-1">An ECT <span class="bcp14">MUST</span> contain the following standard JWT claims <span>[<a href="#RFC7519" class="cite xref">RFC7519</a>]</span>:<a href="#section-3.2.1-1" class="pilcrow"></a></p>
<span class="break"></span><dl class="dlParallel" id="section-3.2.1-2">
<dt id="section-3.2.1-2.1">iss:</dt>
<dd style="margin-left: 1.5em" id="section-3.2.1-2.2">
<p id="section-3.2.1-2.2.1"><span class="bcp14">REQUIRED</span>. StringOrURI. A URI identifying the issuer of the
ECT. In WIMSE deployments, this <span class="bcp14">SHOULD</span> be the workload's
SPIFFE ID in the format <code>spiffe://&lt;trust-domain&gt;/&lt;path&gt;</code>,
matching the "sub" claim of the agent's WIT. Non-WIMSE
deployments <span class="bcp14">MAY</span> use other URI schemes (e.g., HTTPS URLs or
URN:UUID identifiers).<a href="#section-3.2.1-2.2.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-3.2.1-2.3">aud:</dt>
<dd style="margin-left: 1.5em" id="section-3.2.1-2.4">
<p id="section-3.2.1-2.4.1"><span class="bcp14">REQUIRED</span>. StringOrURI or array of StringOrURI. The intended
recipient(s) of the ECT. The "aud" claim <span class="bcp14">SHOULD</span> contain the
identifiers of all entities that will verify the ECT. When
an ECT must be verified by both the next agent and the audit
ledger independently, "aud" <span class="bcp14">MUST</span> be an array containing both
identifiers. Each verifier checks that its own identity
appears in "aud".<a href="#section-3.2.1-2.4.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-3.2.1-2.5">iat:</dt>
<dd style="margin-left: 1.5em" id="section-3.2.1-2.6">
<p id="section-3.2.1-2.6.1"><span class="bcp14">REQUIRED</span>. NumericDate. The time at which the ECT was issued.<a href="#section-3.2.1-2.6.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-3.2.1-2.7">exp:</dt>
<dd style="margin-left: 1.5em" id="section-3.2.1-2.8">
<p id="section-3.2.1-2.8.1"><span class="bcp14">REQUIRED</span>. NumericDate. The expiration time of the ECT.
Implementations <span class="bcp14">SHOULD</span> set this to 5 to 15 minutes after "iat".<a href="#section-3.2.1-2.8.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-3.2.1-2.9">jti:</dt>
<dd style="margin-left: 1.5em" id="section-3.2.1-2.10">
<p id="section-3.2.1-2.10.1"><span class="bcp14">REQUIRED</span>. String. A unique identifier for both the ECT and
the task it records, in UUID format <span>[<a href="#RFC9562" class="cite xref">RFC9562</a>]</span>. The "jti"
serves as both the token identifier (for replay detection) and
the task identifier (for DAG parent references in "par").
Receivers <span class="bcp14">MUST</span> reject ECTs whose "jti" has already been seen
within the expiration window. When "wid" is present,
uniqueness is scoped to the workflow; when "wid" is absent,
uniqueness <span class="bcp14">MUST</span> be enforced globally across the ECT store.<a href="#section-3.2.1-2.10.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
</dl>
</section>
</div>
<div id="exec-claims">
<section id="section-3.2.2">
<h4 id="name-execution-context">
<a href="#section-3.2.2" class="section-number selfRef">3.2.2. </a><a href="#name-execution-context" class="section-name selfRef">Execution Context</a>
</h4>
<p id="section-3.2.2-1">The following claims are defined by this specification:<a href="#section-3.2.2-1" class="pilcrow"></a></p>
<span class="break"></span><dl class="dlParallel" id="section-3.2.2-2">
<dt id="section-3.2.2-2.1">wid:</dt>
<dd style="margin-left: 1.5em" id="section-3.2.2-2.2">
<p id="section-3.2.2-2.2.1"><span class="bcp14">OPTIONAL</span>. String. A workflow identifier that groups related
ECTs into a single workflow. When present, <span class="bcp14">MUST</span> be a UUID
<span>[<a href="#RFC9562" class="cite xref">RFC9562</a>]</span>.<a href="#section-3.2.2-2.2.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-3.2.2-2.3">exec_act:</dt>
<dd style="margin-left: 1.5em" id="section-3.2.2-2.4">
<p id="section-3.2.2-2.4.1"><span class="bcp14">REQUIRED</span>. String. The action or task type identifier describing
what the agent performed (e.g., "process_payment",
"validate_safety"). This claim name avoids collision with the
"act" (Actor) claim registered by <span>[<a href="#RFC8693" class="cite xref">RFC8693</a>]</span>.<a href="#section-3.2.2-2.4.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-3.2.2-2.5">par:</dt>
<dd style="margin-left: 1.5em" id="section-3.2.2-2.6">
<p id="section-3.2.2-2.6.1"><span class="bcp14">REQUIRED</span>. Array of strings. Parent task identifiers
representing DAG dependencies. Each element <span class="bcp14">MUST</span> be the "jti"
value of a previously verified ECT. An empty array indicates
a root task with no dependencies. A workflow <span class="bcp14">MAY</span> contain
multiple root tasks.<a href="#section-3.2.2-2.6.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
</dl>
</section>
</div>
<div id="data-integrity-claims">
<section id="section-3.2.3">
<h4 id="name-data-integrity">
<a href="#section-3.2.3" class="section-number selfRef">3.2.3. </a><a href="#name-data-integrity" class="section-name selfRef">Data Integrity</a>
</h4>
<p id="section-3.2.3-1">The following claims provide integrity verification for task
inputs and outputs without revealing the data itself:<a href="#section-3.2.3-1" class="pilcrow"></a></p>
<span class="break"></span><dl class="dlParallel" id="section-3.2.3-2">
<dt id="section-3.2.3-2.1">inp_hash:</dt>
<dd style="margin-left: 1.5em" id="section-3.2.3-2.2">
<p id="section-3.2.3-2.2.1"><span class="bcp14">OPTIONAL</span>. String. The base64url encoding (without padding) of
the SHA-256 hash of the input data, computed over the raw octets
of the input. SHA-256 is the mandatory algorithm with no
algorithm prefix in the value, consistent with <span>[<a href="#RFC9449" class="cite xref">RFC9449</a>]</span> and
<span>[<a href="#I-D.ietf-wimse-s2s-protocol" class="cite xref">I-D.ietf-wimse-s2s-protocol</a>]</span>.<a href="#section-3.2.3-2.2.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-3.2.3-2.3">out_hash:</dt>
<dd style="margin-left: 1.5em" id="section-3.2.3-2.4">
<p id="section-3.2.3-2.4.1"><span class="bcp14">OPTIONAL</span>. String. The base64url encoding (without padding) of
the SHA-256 hash of the output data, using the same format as
"inp_hash".<a href="#section-3.2.3-2.4.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
</dl>
</section>
</div>
<div id="extension-claims">
<section id="section-3.2.4">
<h4 id="name-extensions">
<a href="#section-3.2.4" class="section-number selfRef">3.2.4. </a><a href="#name-extensions" class="section-name selfRef">Extensions</a>
</h4>
<span class="break"></span><dl class="dlParallel" id="section-3.2.4-1">
<dt id="section-3.2.4-1.1">ext:</dt>
<dd style="margin-left: 1.5em" id="section-3.2.4-1.2">
<p id="section-3.2.4-1.2.1"><span class="bcp14">OPTIONAL</span>. Object. A general-purpose extension object for
domain-specific claims not defined by this specification.
Implementations that do not understand extension claims <span class="bcp14">MUST</span>
ignore them. Extension key names <span class="bcp14">SHOULD</span> use reverse domain
notation (e.g., "com.example.custom_field") to avoid
collisions. The serialized "ext" object <span class="bcp14">SHOULD NOT</span> exceed
4096 bytes and <span class="bcp14">SHOULD NOT</span> exceed a nesting depth of 5 levels.<a href="#section-3.2.4-1.2.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
</dl>
</section>
</div>
</section>
</div>
<div id="complete-ect-example">
<section id="section-3.3">
<h3 id="name-complete-ect-example">
<a href="#section-3.3" class="section-number selfRef">3.3. </a><a href="#name-complete-ect-example" class="section-name selfRef">Complete ECT Example</a>
</h3>
<p id="section-3.3-1">The following is a complete ECT payload example:<a href="#section-3.3-1" class="pilcrow"></a></p>
<span id="name-complete-ect-payload-exampl"></span><div id="fig-full-ect">
<figure id="figure-2">
<div class="lang-json sourcecode" id="section-3.3-2.1">
<pre>
{
"iss": "spiffe://example.com/agent/clinical",
"aud": "spiffe://example.com/agent/safety",
"iat": 1772064150,
"exp": 1772064750,
"jti": "550e8400-e29b-41d4-a716-446655440001",
"wid": "a0b1c2d3-e4f5-6789-abcd-ef0123456789",
"exec_act": "recommend_treatment",
"par": [],
"inp_hash": "n4bQgYhMfWWaL-qgxVrQFaO_TxsrC4Is0V1sFbDwCgg",
"out_hash": "LCa0a2j_xo_5m0U8HTBBNBNCLXBkg7-g-YpeiGJm564",
"ext": {
"com.example.trace_id": "abc123"
}
}
</pre>
</div>
<figcaption><a href="#figure-2" class="selfRef">Figure 2</a>:
<a href="#name-complete-ect-payload-exampl" class="selfRef">Complete ECT Payload Example</a>
</figcaption></figure>
</div>
</section>
</div>
</section>
</div>
<div id="http-header">
<section id="section-4">
<h2 id="name-http-header-transport">
<a href="#section-4" class="section-number selfRef">4. </a><a href="#name-http-header-transport" class="section-name selfRef">HTTP Header Transport</a>
</h2>
<div id="execution-context-header-field">
<section id="section-4.1">
<h3 id="name-execution-context-header-fi">
<a href="#section-4.1" class="section-number selfRef">4.1. </a><a href="#name-execution-context-header-fi" class="section-name selfRef">Execution-Context Header Field</a>
</h3>
<p id="section-4.1-1">This specification defines the Execution-Context HTTP header field
<span>[<a href="#RFC9110" class="cite xref">RFC9110</a>]</span> for transporting ECTs between agents.<a href="#section-4.1-1" class="pilcrow"></a></p>
<p id="section-4.1-2">The header field value is the ECT in JWS Compact Serialization
format <span>[<a href="#RFC7515" class="cite xref">RFC7515</a>]</span>. The value consists of three Base64url-encoded
parts separated by period (".") characters.<a href="#section-4.1-2" class="pilcrow"></a></p>
<p id="section-4.1-3">An agent sending a request to another agent includes the
Execution-Context header alongside the WIMSE Workload-Identity
header. When a Workload Proof Token (WPT) is available per
<span>[<a href="#I-D.ietf-wimse-s2s-protocol" class="cite xref">I-D.ietf-wimse-s2s-protocol</a>]</span>, agents <span class="bcp14">SHOULD</span> include it
alongside the WIT and ECT.<a href="#section-4.1-3" class="pilcrow"></a></p>
<span id="name-http-request-with-ect-heade"></span><div id="fig-http-example">
<figure id="figure-3">
<div class="alignLeft art-text artwork" id="section-4.1-4.1">
<pre>
GET /api/safety-check HTTP/1.1
Host: safety-agent.example.com
Workload-Identity: eyJhbGci...WIT...
Execution-Context: eyJhbGci...ECT...
</pre>
</div>
<figcaption><a href="#figure-3" class="selfRef">Figure 3</a>:
<a href="#name-http-request-with-ect-heade" class="selfRef">HTTP Request with ECT Header</a>
</figcaption></figure>
</div>
<p id="section-4.1-5">When multiple parent tasks contribute context to a single request,
multiple Execution-Context header field lines <span class="bcp14">MAY</span> be included, each
carrying a separate ECT in JWS Compact Serialization format.<a href="#section-4.1-5" class="pilcrow"></a></p>
<p id="section-4.1-6">When a receiver processes multiple Execution-Context headers, it
<span class="bcp14">MUST</span> individually verify each ECT per the procedure in
<a href="#verification" class="auto internal xref">Section 6</a>. If any single ECT fails verification, the
receiver <span class="bcp14">MUST</span> reject the entire request. The set of verified
parent task IDs across all received ECTs represents the complete
set of parent dependencies available for the receiving agent's
subsequent ECT.<a href="#section-4.1-6" class="pilcrow"></a></p>
</section>
</div>
</section>
</div>
<div id="dag-validation">
<section id="section-5">
<h2 id="name-dag-validation">
<a href="#section-5" class="section-number selfRef">5. </a><a href="#name-dag-validation" class="section-name selfRef">DAG Validation</a>
</h2>
<p id="section-5-1">ECTs form a Directed Acyclic Graph (DAG) where each task
references its parent tasks via the "par" claim. DAG validation
is performed against the ECT store — either an audit ledger or
the set of parent ECTs received inline.<a href="#section-5-1" class="pilcrow"></a></p>
<p id="section-5-2">When receiving and verifying an ECT, implementations <span class="bcp14">MUST</span> perform
the following DAG validation steps:<a href="#section-5-2" class="pilcrow"></a></p>
<ol start="1" type="1" class="normal type-1" id="section-5-3">
<li id="section-5-3.1">
<p id="section-5-3.1.1">Task ID Uniqueness: The "jti" claim <span class="bcp14">MUST</span> be unique within the
applicable scope (the workflow identified by "wid", or the
entire ECT store if "wid" is absent). If an ECT with the same
"jti" already exists, the ECT <span class="bcp14">MUST</span> be rejected.<a href="#section-5-3.1.1" class="pilcrow"></a></p>
</li>
<li id="section-5-3.2">
<p id="section-5-3.2.1">Parent Existence: Every task identifier listed in the "par"
array <span class="bcp14">MUST</span> correspond to a task that is available in the ECT
store (either previously recorded in the ledger or received
inline as a verified parent ECT). If any parent task is not
found, the ECT <span class="bcp14">MUST</span> be rejected.<a href="#section-5-3.2.1" class="pilcrow"></a></p>
</li>
<li id="section-5-3.3">
<p id="section-5-3.3.1">Temporal Ordering: The "iat" value of every parent task <span class="bcp14">MUST NOT</span> be greater than the "iat" value of the current task plus a
configurable clock skew tolerance (<span class="bcp14">RECOMMENDED</span>: 30 seconds).
That is, for each parent: <code>parent.iat &lt; child.iat +
clock_skew_tolerance</code>. The tolerance accounts for clock skew
between agents; it does not guarantee strict causal ordering
from timestamps alone. Causal ordering is primarily enforced
by the DAG structure (parent existence in the ECT store), not by
timestamps. If any parent task violates this constraint, the
ECT <span class="bcp14">MUST</span> be rejected.<a href="#section-5-3.3.1" class="pilcrow"></a></p>
</li>
<li id="section-5-3.4">
<p id="section-5-3.4.1">Acyclicity: Following the chain of parent references <span class="bcp14">MUST NOT</span>
lead back to the current ECT's "jti". If a cycle is detected,
the ECT <span class="bcp14">MUST</span> be rejected.<a href="#section-5-3.4.1" class="pilcrow"></a></p>
</li>
<li id="section-5-3.5">
<p id="section-5-3.5.1">Trust Domain Consistency: Parent tasks <span class="bcp14">SHOULD</span> belong to the
same trust domain or to a trust domain with which a federation
relationship has been established.<a href="#section-5-3.5.1" class="pilcrow"></a></p>
</li>
</ol>
<p id="section-5-4">To prevent denial-of-service via extremely deep or wide DAGs,
implementations <span class="bcp14">SHOULD</span> enforce a maximum ancestor traversal limit
(<span class="bcp14">RECOMMENDED</span>: 10000 nodes). If the limit is reached before cycle
detection completes, the ECT <span class="bcp14">SHOULD</span> be rejected.<a href="#section-5-4" class="pilcrow"></a></p>
<p id="section-5-5">In distributed deployments, a parent ECT may not yet be available
locally due to replication lag. Implementations <span class="bcp14">MAY</span> defer
validation to allow parent ECTs to arrive, but <span class="bcp14">MUST NOT</span> treat
the ECT as verified until all parent references are resolved.<a href="#section-5-5" class="pilcrow"></a></p>
</section>
</div>
<div id="verification">
<section id="section-6">
<h2 id="name-signature-and-token-verific">
<a href="#section-6" class="section-number selfRef">6. </a><a href="#name-signature-and-token-verific" class="section-name selfRef">Signature and Token Verification</a>
</h2>
<div id="verification-procedure">
<section id="section-6.1">
<h3 id="name-verification-procedure">
<a href="#section-6.1" class="section-number selfRef">6.1. </a><a href="#name-verification-procedure" class="section-name selfRef">Verification Procedure</a>
</h3>
<p id="section-6.1-1">When an agent receives an ECT, it <span class="bcp14">MUST</span> perform the following
verification steps in order:<a href="#section-6.1-1" class="pilcrow"></a></p>
<ol start="1" type="1" class="normal type-1" id="section-6.1-2">
<li id="section-6.1-2.1">
<p id="section-6.1-2.1.1">Parse the JWS Compact Serialization to extract the JOSE header,
payload, and signature components per <span>[<a href="#RFC7515" class="cite xref">RFC7515</a>]</span>.<a href="#section-6.1-2.1.1" class="pilcrow"></a></p>
</li>
<li id="section-6.1-2.2">
<p id="section-6.1-2.2.1">Verify that the "typ" header parameter is "wimse-exec+jwt".<a href="#section-6.1-2.2.1" class="pilcrow"></a></p>
</li>
<li id="section-6.1-2.3">
<p id="section-6.1-2.3.1">Verify that the "alg" header parameter appears in the
verifier's configured allowlist of accepted signing algorithms.
The allowlist <span class="bcp14">MUST NOT</span> include "none" or any symmetric
algorithm (e.g., HS256, HS384, HS512). Implementations <span class="bcp14">MUST</span>
include ES256 in the allowlist; additional asymmetric algorithms
<span class="bcp14">MAY</span> be included per deployment policy.<a href="#section-6.1-2.3.1" class="pilcrow"></a></p>
</li>
<li id="section-6.1-2.4">
<p id="section-6.1-2.4.1">Verify the "kid" header parameter references a known, valid
public key from a WIT within the trust domain.<a href="#section-6.1-2.4.1" class="pilcrow"></a></p>
</li>
<li id="section-6.1-2.5">
<p id="section-6.1-2.5.1">Retrieve the public key identified by "kid" and verify the JWS
signature per <span>[<a href="#RFC7515" class="cite xref">RFC7515</a>]</span> Section 5.2.<a href="#section-6.1-2.5.1" class="pilcrow"></a></p>
</li>
<li id="section-6.1-2.6">
<p id="section-6.1-2.6.1">Verify that the signing key identified by "kid" has not been
revoked within the trust domain. Implementations <span class="bcp14">MUST</span> check
the key's revocation status using the trust domain's key
lifecycle mechanism (e.g., certificate revocation list, OCSP,
or SPIFFE trust bundle updates).<a href="#section-6.1-2.6.1" class="pilcrow"></a></p>
</li>
<li id="section-6.1-2.7">
<p id="section-6.1-2.7.1">Verify the "alg" header parameter matches the algorithm in the
corresponding WIT.<a href="#section-6.1-2.7.1" class="pilcrow"></a></p>
</li>
<li id="section-6.1-2.8">
<p id="section-6.1-2.8.1">Verify the "iss" claim matches the "sub" claim of the WIT
associated with the "kid" public key.<a href="#section-6.1-2.8.1" class="pilcrow"></a></p>
</li>
<li id="section-6.1-2.9">
<p id="section-6.1-2.9.1">Verify the "aud" claim contains the verifier's own workload
identity. When "aud" is an array, it is sufficient that the
verifier's identity appears as one element; the presence of
other audience values does not cause verification failure.
When the verifier is the audit ledger, the ledger's own
identity <span class="bcp14">MUST</span> appear in "aud".<a href="#section-6.1-2.9.1" class="pilcrow"></a></p>
</li>
<li id="section-6.1-2.10">
<p id="section-6.1-2.10.1">Verify the "exp" claim indicates the ECT has not expired.<a href="#section-6.1-2.10.1" class="pilcrow"></a></p>
</li>
<li id="section-6.1-2.11">
<p id="section-6.1-2.11.1">Verify the "iat" claim is not unreasonably far in the past
(implementation-specific threshold, <span class="bcp14">RECOMMENDED</span> maximum of
15 minutes) and is not unreasonably far in the future
(<span class="bcp14">RECOMMENDED</span>: no more than 30 seconds ahead of the
verifier's current time, to account for clock skew).<a href="#section-6.1-2.11.1" class="pilcrow"></a></p>
</li>
<li id="section-6.1-2.12">
<p id="section-6.1-2.12.1">Verify all required claims ("jti", "exec_act", "par") are
present and well-formed.<a href="#section-6.1-2.12.1" class="pilcrow"></a></p>
</li>
<li id="section-6.1-2.13">
<p id="section-6.1-2.13.1">Perform DAG validation per <a href="#dag-validation" class="auto internal xref">Section 5</a>.<a href="#section-6.1-2.13.1" class="pilcrow"></a></p>
</li>
<li id="section-6.1-2.14">
<p id="section-6.1-2.14.1">If all checks pass and an audit ledger is deployed, the ECT
<span class="bcp14">SHOULD</span> be appended to the ledger.<a href="#section-6.1-2.14.1" class="pilcrow"></a></p>
</li>
</ol>
<p id="section-6.1-3">If any verification step fails, the ECT <span class="bcp14">MUST</span> be rejected and the
failure <span class="bcp14">MUST</span> be logged for audit purposes. Error messages
<span class="bcp14">SHOULD NOT</span> reveal whether specific parent task IDs exist in the
ECT store, to prevent information disclosure.<a href="#section-6.1-3" class="pilcrow"></a></p>
<p id="section-6.1-4">When ECT verification fails during HTTP request processing, the
receiving agent <span class="bcp14">SHOULD</span> respond with HTTP 403 (Forbidden) if the
WIT is valid but the ECT is invalid, and HTTP 401
(Unauthorized) if the ECT signature verification fails. The
response body <span class="bcp14">SHOULD</span> include a generic error indicator without
revealing which specific verification step failed. The receiving
agent <span class="bcp14">MUST NOT</span> process the requested action when ECT verification
fails.<a href="#section-6.1-4" class="pilcrow"></a></p>
</section>
</div>
</section>
</div>
<div id="ledger-interface">
<section id="section-7">
<h2 id="name-audit-ledger-interface">
<a href="#section-7" class="section-number selfRef">7. </a><a href="#name-audit-ledger-interface" class="section-name selfRef">Audit Ledger Interface</a>
</h2>
<p id="section-7-1">ECTs <span class="bcp14">MAY</span> be recorded in an immutable audit ledger for compliance
verification and post-hoc analysis. A ledger is <span class="bcp14">RECOMMENDED</span> for
regulated environments but is not required for point-to-point
operation. This specification does not mandate a specific storage
technology. Implementations <span class="bcp14">MAY</span> use append-only logs, databases
with cryptographic commitment schemes, distributed ledgers, or
any storage mechanism that provides the required properties.<a href="#section-7-1" class="pilcrow"></a></p>
<p id="section-7-2">When an audit ledger is deployed, the implementation <span class="bcp14">MUST</span> provide:<a href="#section-7-2" class="pilcrow"></a></p>
<ol start="1" type="1" class="normal type-1" id="section-7-3">
<li id="section-7-3.1">
<p id="section-7-3.1.1">Append-only semantics: Once an ECT is recorded, it <span class="bcp14">MUST NOT</span> be
modified or deleted.<a href="#section-7-3.1.1" class="pilcrow"></a></p>
</li>
<li id="section-7-3.2">
<p id="section-7-3.2.1">Ordering: The ledger <span class="bcp14">MUST</span> maintain a total ordering of ECT
entries via a monotonically increasing sequence number.<a href="#section-7-3.2.1" class="pilcrow"></a></p>
</li>
<li id="section-7-3.3">
<p id="section-7-3.3.1">Lookup by ECT ID: The ledger <span class="bcp14">MUST</span> support efficient retrieval
of ECT entries by "jti" value.<a href="#section-7-3.3.1" class="pilcrow"></a></p>
</li>
<li id="section-7-3.4">
<p id="section-7-3.4.1">Integrity verification: The ledger <span class="bcp14">SHOULD</span> provide a mechanism
to verify that no entries have been tampered with (e.g.,
hash chains or Merkle trees).<a href="#section-7-3.4.1" class="pilcrow"></a></p>
</li>
</ol>
<p id="section-7-4">The ledger <span class="bcp14">SHOULD</span> be maintained by an entity independent of the
workflow agents to reduce the risk of collusion.<a href="#section-7-4" class="pilcrow"></a></p>
</section>
</div>
<div id="security-considerations">
<section id="section-8">
<h2 id="name-security-considerations">
<a href="#section-8" class="section-number selfRef">8. </a><a href="#name-security-considerations" class="section-name selfRef">Security Considerations</a>
</h2>
<div id="threat-model">
<section id="section-8.1">
<h3 id="name-threat-model">
<a href="#section-8.1" class="section-number selfRef">8.1. </a><a href="#name-threat-model" class="section-name selfRef">Threat Model</a>
</h3>
<p id="section-8.1-1">The threat model considers: (1) a malicious agent that creates
false ECT claims, (2) an agent whose private key has been
compromised, (3) a ledger tamperer attempting to modify recorded
entries, and (4) a time manipulator altering timestamps to affect
perceived ordering.<a href="#section-8.1-1" class="pilcrow"></a></p>
</section>
</div>
<div id="self-assertion-limitation">
<section id="section-8.2">
<h3 id="name-self-assertion-limitation">
<a href="#section-8.2" class="section-number selfRef">8.2. </a><a href="#name-self-assertion-limitation" class="section-name selfRef">Self-Assertion Limitation</a>
</h3>
<p id="section-8.2-1">ECTs are self-asserted by the executing agent. The agent claims
what it did, and this claim is signed with its private key. A
compromised or malicious agent could create ECTs with false claims
(e.g., claiming an action was performed when it was not).<a href="#section-8.2-1" class="pilcrow"></a></p>
<p id="section-8.2-2">ECTs do not independently verify that:<a href="#section-8.2-2" class="pilcrow"></a></p>
<ul class="normal">
<li class="normal" id="section-8.2-3.1">
<p id="section-8.2-3.1.1">The claimed execution actually occurred as described<a href="#section-8.2-3.1.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-8.2-3.2">
<p id="section-8.2-3.2.1">The input/output hashes correspond to the actual data processed<a href="#section-8.2-3.2.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-8.2-3.3">
<p id="section-8.2-3.3.1">The agent faithfully performed the stated action<a href="#section-8.2-3.3.1" class="pilcrow"></a></p>
</li>
</ul>
<p id="section-8.2-4">The trustworthiness of ECT claims depends on the trustworthiness
of the signing agent and the integrity of the broader deployment
environment. ECTs provide a technical mechanism for execution
recording; they do not by themselves satisfy any specific
regulatory compliance requirement.<a href="#section-8.2-4" class="pilcrow"></a></p>
</section>
</div>
<div id="signature-verification">
<section id="section-8.3">
<h3 id="name-signature-verification">
<a href="#section-8.3" class="section-number selfRef">8.3. </a><a href="#name-signature-verification" class="section-name selfRef">Signature Verification</a>
</h3>
<p id="section-8.3-1">ECTs <span class="bcp14">MUST</span> be signed with the agent's private key using JWS
<span>[<a href="#RFC7515" class="cite xref">RFC7515</a>]</span>. The signature algorithm <span class="bcp14">MUST</span> match the algorithm
specified in the agent's WIT. Receivers <span class="bcp14">MUST</span> verify the ECT
signature against the WIT public key before processing any
claims. Receivers <span class="bcp14">MUST</span> verify that the signing key has not been
revoked within the trust domain (see step 6 in
<a href="#verification" class="auto internal xref">Section 6</a>).<a href="#section-8.3-1" class="pilcrow"></a></p>
<p id="section-8.3-2">If signature verification fails or if the signing key has been
revoked, the ECT <span class="bcp14">MUST</span> be rejected entirely and the failure <span class="bcp14">MUST</span>
be logged.<a href="#section-8.3-2" class="pilcrow"></a></p>
<p id="section-8.3-3">Implementations <span class="bcp14">MUST</span> use established JWS libraries and <span class="bcp14">MUST NOT</span>
implement custom signature verification.<a href="#section-8.3-3" class="pilcrow"></a></p>
</section>
</div>
<div id="replay-attack-prevention">
<section id="section-8.4">
<h3 id="name-replay-attack-prevention">
<a href="#section-8.4" class="section-number selfRef">8.4. </a><a href="#name-replay-attack-prevention" class="section-name selfRef">Replay Attack Prevention</a>
</h3>
<p id="section-8.4-1">ECTs include short expiration times (<span class="bcp14">RECOMMENDED</span>: 5-15 minutes)
and audience restriction via "aud" to limit replay attacks.
Implementations <span class="bcp14">MUST</span> maintain a cache of recently-seen "jti"
values and <span class="bcp14">MUST</span> reject ECTs with duplicate "jti" values. Each
ECT is cryptographically bound to the issuing agent via "kid";
verifiers <span class="bcp14">MUST</span> confirm that "kid" resolves to the "iss" agent's
key (step 8 in <a href="#verification" class="auto internal xref">Section 6</a>).<a href="#section-8.4-1" class="pilcrow"></a></p>
</section>
</div>
<div id="man-in-the-middle-protection">
<section id="section-8.5">
<h3 id="name-man-in-the-middle-protectio">
<a href="#section-8.5" class="section-number selfRef">8.5. </a><a href="#name-man-in-the-middle-protectio" class="section-name selfRef">Man-in-the-Middle Protection</a>
</h3>
<p id="section-8.5-1">ECTs <span class="bcp14">MUST</span> be transmitted over TLS or mTLS connections. When used
with <span>[<a href="#I-D.ietf-wimse-s2s-protocol" class="cite xref">I-D.ietf-wimse-s2s-protocol</a>]</span>, transport security is
already established.<a href="#section-8.5-1" class="pilcrow"></a></p>
</section>
</div>
<div id="key-compromise">
<section id="section-8.6">
<h3 id="name-key-compromise">
<a href="#section-8.6" class="section-number selfRef">8.6. </a><a href="#name-key-compromise" class="section-name selfRef">Key Compromise</a>
</h3>
<p id="section-8.6-1">If an agent's private key is compromised, an attacker can forge
ECTs that appear to originate from that agent. Mitigations:<a href="#section-8.6-1" class="pilcrow"></a></p>
<ul class="normal">
<li class="normal" id="section-8.6-2.1">
<p id="section-8.6-2.1.1">Implementations <span class="bcp14">SHOULD</span> use short-lived keys and rotate them
frequently.<a href="#section-8.6-2.1.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-8.6-2.2">
<p id="section-8.6-2.2.1">Private keys <span class="bcp14">SHOULD</span> be stored in hardware security modules or
equivalent secure key storage.<a href="#section-8.6-2.2.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-8.6-2.3">
<p id="section-8.6-2.3.1">Trust domains <span class="bcp14">MUST</span> support rapid key revocation.<a href="#section-8.6-2.3.1" class="pilcrow"></a></p>
</li>
</ul>
<p id="section-8.6-3">ECTs recorded before key revocation remain valid historical
records but <span class="bcp14">SHOULD</span> be flagged for audit purposes. New ECTs
<span class="bcp14">MUST NOT</span> reference a parent ECT whose signing key is known to
be revoked at creation time.<a href="#section-8.6-3" class="pilcrow"></a></p>
</section>
</div>
<div id="collusion-and-false-claims">
<section id="section-8.7">
<h3 id="name-collusion-and-dag-integrity">
<a href="#section-8.7" class="section-number selfRef">8.7. </a><a href="#name-collusion-and-dag-integrity" class="section-name selfRef">Collusion and DAG Integrity</a>
</h3>
<p id="section-8.7-1">A single malicious agent cannot forge parent task references
because DAG validation requires parent tasks to exist in the ECT
store. However, multiple colluding agents could create a false
execution history. Additionally, a malicious agent may omit
actual parent dependencies from "par" to hide influences on its
output; because ECTs are self-asserted
(<a href="#self-assertion-limitation" class="auto internal xref">Section 8.2</a>), no mechanism can force complete
dependency declaration.<a href="#section-8.7-1" class="pilcrow"></a></p>
<p id="section-8.7-2">Mitigations include:<a href="#section-8.7-2" class="pilcrow"></a></p>
<ul class="normal">
<li class="normal" id="section-8.7-3.1">
<p id="section-8.7-3.1.1">The ledger <span class="bcp14">SHOULD</span> be maintained by an entity independent of the
workflow agents.<a href="#section-8.7-3.1.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-8.7-3.2">
<p id="section-8.7-3.2.1">Multiple independent ledger replicas can be compared for
consistency.<a href="#section-8.7-3.2.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-8.7-3.3">
<p id="section-8.7-3.3.1">External auditors can compare the declared DAG against expected
workflow patterns.<a href="#section-8.7-3.3.1" class="pilcrow"></a></p>
</li>
</ul>
<p id="section-8.7-4">Verifiers <span class="bcp14">SHOULD</span> validate that the declared "wid" of parent ECTs
matches the "wid" of the child ECT, rejecting cross-workflow
parent references unless explicitly permitted by deployment
policy.<a href="#section-8.7-4" class="pilcrow"></a></p>
</section>
</div>
<div id="privilege-escalation-via-ects">
<section id="section-8.8">
<h3 id="name-privilege-escalation-via-ec">
<a href="#section-8.8" class="section-number selfRef">8.8. </a><a href="#name-privilege-escalation-via-ec" class="section-name selfRef">Privilege Escalation via ECTs</a>
</h3>
<p id="section-8.8-1">ECTs record execution history; they do not convey authorization.
Verifiers <span class="bcp14">MUST NOT</span> interpret the presence of an ECT, or a
particular set of parent references in "par", as an authorization
grant. Authorization decisions <span class="bcp14">MUST</span> remain with the identity and
authorization layer (WIT, WPT, and deployment policy).<a href="#section-8.8-1" class="pilcrow"></a></p>
</section>
</div>
<div id="denial-of-service">
<section id="section-8.9">
<h3 id="name-denial-of-service">
<a href="#section-8.9" class="section-number selfRef">8.9. </a><a href="#name-denial-of-service" class="section-name selfRef">Denial of Service</a>
</h3>
<p id="section-8.9-1">Implementations <span class="bcp14">SHOULD</span> apply rate limiting to prevent excessive
ECT submissions. DAG validation <span class="bcp14">SHOULD</span> be performed after
signature verification to avoid wasting resources on unsigned
tokens.<a href="#section-8.9-1" class="pilcrow"></a></p>
</section>
</div>
<div id="timestamp-accuracy">
<section id="section-8.10">
<h3 id="name-timestamp-accuracy">
<a href="#section-8.10" class="section-number selfRef">8.10. </a><a href="#name-timestamp-accuracy" class="section-name selfRef">Timestamp Accuracy</a>
</h3>
<p id="section-8.10-1">Implementations <span class="bcp14">SHOULD</span> use synchronized time sources (e.g., NTP)
and <span class="bcp14">SHOULD</span> allow a configurable clock skew tolerance (<span class="bcp14">RECOMMENDED</span>:
30 seconds). Cross-organizational deployments <span class="bcp14">MAY</span> require a
higher tolerance and <span class="bcp14">SHOULD</span> document the configured value.<a href="#section-8.10-1" class="pilcrow"></a></p>
</section>
</div>
<div id="ect-size-constraints">
<section id="section-8.11">
<h3 id="name-ect-size-constraints">
<a href="#section-8.11" class="section-number selfRef">8.11. </a><a href="#name-ect-size-constraints" class="section-name selfRef">ECT Size Constraints</a>
</h3>
<p id="section-8.11-1">Implementations <span class="bcp14">SHOULD</span> limit the "par" array to a maximum of
256 entries. See <a href="#extension-claims" class="auto internal xref">Section 3.2.4</a> for "ext" size limits.<a href="#section-8.11-1" class="pilcrow"></a></p>
</section>
</div>
</section>
</div>
<div id="privacy-considerations">
<section id="section-9">
<h2 id="name-privacy-considerations">
<a href="#section-9" class="section-number selfRef">9. </a><a href="#name-privacy-considerations" class="section-name selfRef">Privacy Considerations</a>
</h2>
<div id="data-exposure-in-ects">
<section id="section-9.1">
<h3 id="name-data-exposure-in-ects">
<a href="#section-9.1" class="section-number selfRef">9.1. </a><a href="#name-data-exposure-in-ects" class="section-name selfRef">Data Exposure in ECTs</a>
</h3>
<p id="section-9.1-1">ECTs necessarily reveal:<a href="#section-9.1-1" class="pilcrow"></a></p>
<ul class="normal">
<li class="normal" id="section-9.1-2.1">
<p id="section-9.1-2.1.1">Agent identities ("iss", "aud") for accountability purposes<a href="#section-9.1-2.1.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-9.1-2.2">
<p id="section-9.1-2.2.1">Action descriptions ("exec_act") for audit trail completeness<a href="#section-9.1-2.2.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-9.1-2.3">
<p id="section-9.1-2.3.1">Timestamps ("iat", "exp") for temporal ordering<a href="#section-9.1-2.3.1" class="pilcrow"></a></p>
</li>
</ul>
<p id="section-9.1-3">ECTs are designed to NOT reveal:<a href="#section-9.1-3" class="pilcrow"></a></p>
<ul class="normal">
<li class="normal" id="section-9.1-4.1">
<p id="section-9.1-4.1.1">Actual input or output data values (replaced with cryptographic
hashes via "inp_hash" and "out_hash")<a href="#section-9.1-4.1.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-9.1-4.2">
<p id="section-9.1-4.2.1">Internal computation details or intermediate steps<a href="#section-9.1-4.2.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-9.1-4.3">
<p id="section-9.1-4.3.1">Proprietary algorithms or intellectual property<a href="#section-9.1-4.3.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="section-9.1-4.4">
<p id="section-9.1-4.4.1">Personally identifiable information (PII)<a href="#section-9.1-4.4.1" class="pilcrow"></a></p>
</li>
</ul>
</section>
</div>
<div id="data-minimization">
<section id="section-9.2">
<h3 id="name-data-minimization">
<a href="#section-9.2" class="section-number selfRef">9.2. </a><a href="#name-data-minimization" class="section-name selfRef">Data Minimization</a>
</h3>
<p id="section-9.2-1">Implementations <span class="bcp14">SHOULD</span> minimize the information included in ECTs.
The "exec_act" claim <span class="bcp14">SHOULD</span> use structured identifiers (e.g.,
"process_payment") rather than natural language descriptions.
Extension keys in "ext" (<a href="#extension-claims" class="auto internal xref">Section 3.2.4</a>) deserve particular
attention: human-readable values risk exposing sensitive operational
details. See <a href="#extension-claims" class="auto internal xref">Section 3.2.4</a> for guidance on using
structured identifiers.<a href="#section-9.2-1" class="pilcrow"></a></p>
</section>
</div>
<div id="storage-and-access-control">
<section id="section-9.3">
<h3 id="name-storage-and-access-control">
<a href="#section-9.3" class="section-number selfRef">9.3. </a><a href="#name-storage-and-access-control" class="section-name selfRef">Storage and Access Control</a>
</h3>
<p id="section-9.3-1">ECTs stored in audit ledgers <span class="bcp14">SHOULD</span> be access-controlled so that
only authorized auditors can read them. Implementations <span class="bcp14">SHOULD</span>
consider encryption at rest for ledger storage. ECTs provide
structural records of execution ordering; they are not intended
for public disclosure.<a href="#section-9.3-1" class="pilcrow"></a></p>
<p id="section-9.3-2">Full input and output data (corresponding to the hashes in ECTs)
<span class="bcp14">SHOULD</span> be stored separately from the ledger with additional access
controls, since auditors may need to verify hash correctness but
general access to the data values is not needed.<a href="#section-9.3-2" class="pilcrow"></a></p>
</section>
</div>
</section>
</div>
<div id="iana-considerations">
<section id="section-10">
<h2 id="name-iana-considerations">
<a href="#section-10" class="section-number selfRef">10. </a><a href="#name-iana-considerations" class="section-name selfRef">IANA Considerations</a>
</h2>
<div id="media-type-registration">
<section id="section-10.1">
<h3 id="name-media-type-registration">
<a href="#section-10.1" class="section-number selfRef">10.1. </a><a href="#name-media-type-registration" class="section-name selfRef">Media Type Registration</a>
</h3>
<p id="section-10.1-1">This document requests registration of the following media type
in the "Media Types" registry maintained by IANA:<a href="#section-10.1-1" class="pilcrow"></a></p>
<span class="break"></span><dl class="dlParallel" id="section-10.1-2">
<dt id="section-10.1-2.1">Type name:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.2">
<p id="section-10.1-2.2.1">application<a href="#section-10.1-2.2.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.3">Subtype name:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.4">
<p id="section-10.1-2.4.1">wimse-exec+jwt<a href="#section-10.1-2.4.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.5">Required parameters:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.6">
<p id="section-10.1-2.6.1">none<a href="#section-10.1-2.6.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.7">Optional parameters:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.8">
<p id="section-10.1-2.8.1">none<a href="#section-10.1-2.8.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.9">Encoding considerations:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.10">
<p id="section-10.1-2.10.1">8bit; an ECT is a JWT that is a JWS using the Compact
Serialization, which is a sequence of Base64url-encoded values
separated by period characters.<a href="#section-10.1-2.10.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.11">Security considerations:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.12">
<p id="section-10.1-2.12.1">See the Security Considerations section of this document.<a href="#section-10.1-2.12.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.13">Interoperability considerations:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.14">
<p id="section-10.1-2.14.1">none<a href="#section-10.1-2.14.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.15">Published specification:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.16">
<p id="section-10.1-2.16.1">This document<a href="#section-10.1-2.16.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.17">Applications that use this media type:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.18">
<p id="section-10.1-2.18.1">Applications that implement agentic workflows requiring execution
context tracing and audit trails.<a href="#section-10.1-2.18.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.19">Additional information:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.20">
<p id="section-10.1-2.20.1">Magic number(s): none
File extension(s): none
Macintosh file type code(s): none<a href="#section-10.1-2.20.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.21">Person and email address to contact for further information:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.22">
<p id="section-10.1-2.22.1">Christian Nennemann, ietf@nennemann.de<a href="#section-10.1-2.22.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.23">Intended usage:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.24">
<p id="section-10.1-2.24.1">COMMON<a href="#section-10.1-2.24.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.25">Restrictions on usage:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.26">
<p id="section-10.1-2.26.1">none<a href="#section-10.1-2.26.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.27">Author:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.28">
<p id="section-10.1-2.28.1">Christian Nennemann<a href="#section-10.1-2.28.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.1-2.29">Change controller:</dt>
<dd style="margin-left: 1.5em" id="section-10.1-2.30">
<p id="section-10.1-2.30.1">IETF<a href="#section-10.1-2.30.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
</dl>
</section>
</div>
<div id="header-registration">
<section id="section-10.2">
<h3 id="name-http-header-field-registrat">
<a href="#section-10.2" class="section-number selfRef">10.2. </a><a href="#name-http-header-field-registrat" class="section-name selfRef">HTTP Header Field Registration</a>
</h3>
<p id="section-10.2-1">This document requests registration of the following header field
in the "Hypertext Transfer Protocol (HTTP) Field Name Registry"
maintained by IANA:<a href="#section-10.2-1" class="pilcrow"></a></p>
<span class="break"></span><dl class="dlParallel" id="section-10.2-2">
<dt id="section-10.2-2.1">Field name:</dt>
<dd style="margin-left: 1.5em" id="section-10.2-2.2">
<p id="section-10.2-2.2.1">Execution-Context<a href="#section-10.2-2.2.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.2-2.3">Status:</dt>
<dd style="margin-left: 1.5em" id="section-10.2-2.4">
<p id="section-10.2-2.4.1">permanent<a href="#section-10.2-2.4.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
<dt id="section-10.2-2.5">Specification document:</dt>
<dd style="margin-left: 1.5em" id="section-10.2-2.6">
<p id="section-10.2-2.6.1">This document, <a href="#http-header" class="auto internal xref">Section 4</a><a href="#section-10.2-2.6.1" class="pilcrow"></a></p>
</dd>
<dd class="break"></dd>
</dl>
</section>
</div>
<div id="claims-registration">
<section id="section-10.3">
<h3 id="name-jwt-claims-registration">
<a href="#section-10.3" class="section-number selfRef">10.3. </a><a href="#name-jwt-claims-registration" class="section-name selfRef">JWT Claims Registration</a>
</h3>
<p id="section-10.3-1">This document requests registration of the following claims in
the "JSON Web Token Claims" registry maintained by IANA:<a href="#section-10.3-1" class="pilcrow"></a></p>
<span id="name-jwt-claims-registrations"></span><div id="_table-claims">
<table class="center" id="table-1">
<caption>
<a href="#table-1" class="selfRef">Table 1</a>:
<a href="#name-jwt-claims-registrations" class="selfRef">JWT Claims Registrations</a>
</caption>
<thead>
<tr>
<th class="text-center" rowspan="1" colspan="1">Claim Name</th>
<th class="text-left" rowspan="1" colspan="1">Claim Description</th>
<th class="text-center" rowspan="1" colspan="1">Change Controller</th>
<th class="text-center" rowspan="1" colspan="1">Reference</th>
</tr>
</thead>
<tbody>
<tr>
<td class="text-center" rowspan="1" colspan="1">wid</td>
<td class="text-left" rowspan="1" colspan="1">Workflow Identifier</td>
<td class="text-center" rowspan="1" colspan="1">IETF</td>
<td class="text-center" rowspan="1" colspan="1">
<a href="#exec-claims" class="auto internal xref">Section 3.2.2</a>
</td>
</tr>
<tr>
<td class="text-center" rowspan="1" colspan="1">exec_act</td>
<td class="text-left" rowspan="1" colspan="1">Action/Task Type</td>
<td class="text-center" rowspan="1" colspan="1">IETF</td>
<td class="text-center" rowspan="1" colspan="1">
<a href="#exec-claims" class="auto internal xref">Section 3.2.2</a>
</td>
</tr>
<tr>
<td class="text-center" rowspan="1" colspan="1">par</td>
<td class="text-left" rowspan="1" colspan="1">Parent Task Identifiers</td>
<td class="text-center" rowspan="1" colspan="1">IETF</td>
<td class="text-center" rowspan="1" colspan="1">
<a href="#exec-claims" class="auto internal xref">Section 3.2.2</a>
</td>
</tr>
<tr>
<td class="text-center" rowspan="1" colspan="1">inp_hash</td>
<td class="text-left" rowspan="1" colspan="1">Input Data Hash</td>
<td class="text-center" rowspan="1" colspan="1">IETF</td>
<td class="text-center" rowspan="1" colspan="1">
<a href="#data-integrity-claims" class="auto internal xref">Section 3.2.3</a>
</td>
</tr>
<tr>
<td class="text-center" rowspan="1" colspan="1">out_hash</td>
<td class="text-left" rowspan="1" colspan="1">Output Data Hash</td>
<td class="text-center" rowspan="1" colspan="1">IETF</td>
<td class="text-center" rowspan="1" colspan="1">
<a href="#data-integrity-claims" class="auto internal xref">Section 3.2.3</a>
</td>
</tr>
<tr>
<td class="text-center" rowspan="1" colspan="1">ext</td>
<td class="text-left" rowspan="1" colspan="1">Extension Object</td>
<td class="text-center" rowspan="1" colspan="1">IETF</td>
<td class="text-center" rowspan="1" colspan="1">
<a href="#extension-claims" class="auto internal xref">Section 3.2.4</a>
</td>
</tr>
</tbody>
</table>
</div>
</section>
</div>
</section>
</div>
<div id="sec-combined-references">
<section id="section-11">
<h2 id="name-references">
<a href="#section-11" class="section-number selfRef">11. </a><a href="#name-references" class="section-name selfRef">References</a>
</h2>
<div id="sec-normative-references">
<section id="section-11.1">
<h3 id="name-normative-references">
<a href="#section-11.1" class="section-number selfRef">11.1. </a><a href="#name-normative-references" class="section-name selfRef">Normative References</a>
</h3>
<dl class="references">
<dt id="I-D.ietf-wimse-arch">[I-D.ietf-wimse-arch]</dt>
<dd>
<span class="refAuthor">Salowey, J. A.</span>, <span class="refAuthor">Rosomakho, Y.</span>, and <span class="refAuthor">H. Tschofenig</span>, <span class="refTitle">"Workload Identity in a Multi System Environment (WIMSE) Architecture"</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-ietf-wimse-arch-06</span>, <time datetime="2025-09-30" class="refDate">30 September 2025</time>, <span>&lt;<a href="https://datatracker.ietf.org/doc/html/draft-ietf-wimse-arch-06">https://datatracker.ietf.org/doc/html/draft-ietf-wimse-arch-06</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="I-D.ietf-wimse-s2s-protocol">[I-D.ietf-wimse-s2s-protocol]</dt>
<dd>
<span class="refAuthor">Campbell, B.</span>, <span class="refAuthor">Salowey, J. A.</span>, <span class="refAuthor">Schwenkschuster, A.</span>, and <span class="refAuthor">Y. Sheffer</span>, <span class="refTitle">"WIMSE Workload-to-Workload Authentication"</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-ietf-wimse-s2s-protocol-07</span>, <time datetime="2025-10-16" class="refDate">16 October 2025</time>, <span>&lt;<a href="https://datatracker.ietf.org/doc/html/draft-ietf-wimse-s2s-protocol-07">https://datatracker.ietf.org/doc/html/draft-ietf-wimse-s2s-protocol-07</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC2119">[RFC2119]</dt>
<dd>
<span class="refAuthor">Bradner, S.</span>, <span class="refTitle">"Key words for use in RFCs to Indicate Requirement Levels"</span>, <span class="seriesInfo">BCP 14</span>, <span class="seriesInfo">RFC 2119</span>, <span class="seriesInfo">DOI 10.17487/RFC2119</span>, <time datetime="1997-03" class="refDate">March 1997</time>, <span>&lt;<a href="https://www.rfc-editor.org/rfc/rfc2119">https://www.rfc-editor.org/rfc/rfc2119</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7515">[RFC7515]</dt>
<dd>
<span class="refAuthor">Jones, M.</span>, <span class="refAuthor">Bradley, J.</span>, and <span class="refAuthor">N. Sakimura</span>, <span class="refTitle">"JSON Web Signature (JWS)"</span>, <span class="seriesInfo">RFC 7515</span>, <span class="seriesInfo">DOI 10.17487/RFC7515</span>, <time datetime="2015-05" class="refDate">May 2015</time>, <span>&lt;<a href="https://www.rfc-editor.org/rfc/rfc7515">https://www.rfc-editor.org/rfc/rfc7515</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7517">[RFC7517]</dt>
<dd>
<span class="refAuthor">Jones, M.</span>, <span class="refTitle">"JSON Web Key (JWK)"</span>, <span class="seriesInfo">RFC 7517</span>, <span class="seriesInfo">DOI 10.17487/RFC7517</span>, <time datetime="2015-05" class="refDate">May 2015</time>, <span>&lt;<a href="https://www.rfc-editor.org/rfc/rfc7517">https://www.rfc-editor.org/rfc/rfc7517</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7518">[RFC7518]</dt>
<dd>
<span class="refAuthor">Jones, M.</span>, <span class="refTitle">"JSON Web Algorithms (JWA)"</span>, <span class="seriesInfo">RFC 7518</span>, <span class="seriesInfo">DOI 10.17487/RFC7518</span>, <time datetime="2015-05" class="refDate">May 2015</time>, <span>&lt;<a href="https://www.rfc-editor.org/rfc/rfc7518">https://www.rfc-editor.org/rfc/rfc7518</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7519">[RFC7519]</dt>
<dd>
<span class="refAuthor">Jones, M.</span>, <span class="refAuthor">Bradley, J.</span>, and <span class="refAuthor">N. Sakimura</span>, <span class="refTitle">"JSON Web Token (JWT)"</span>, <span class="seriesInfo">RFC 7519</span>, <span class="seriesInfo">DOI 10.17487/RFC7519</span>, <time datetime="2015-05" class="refDate">May 2015</time>, <span>&lt;<a href="https://www.rfc-editor.org/rfc/rfc7519">https://www.rfc-editor.org/rfc/rfc7519</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8174">[RFC8174]</dt>
<dd>
<span class="refAuthor">Leiba, B.</span>, <span class="refTitle">"Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words"</span>, <span class="seriesInfo">BCP 14</span>, <span class="seriesInfo">RFC 8174</span>, <span class="seriesInfo">DOI 10.17487/RFC8174</span>, <time datetime="2017-05" class="refDate">May 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/rfc/rfc8174">https://www.rfc-editor.org/rfc/rfc8174</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC9110">[RFC9110]</dt>
<dd>
<span class="refAuthor">Fielding, R., Ed.</span>, <span class="refAuthor">Nottingham, M., Ed.</span>, and <span class="refAuthor">J. Reschke, Ed.</span>, <span class="refTitle">"HTTP Semantics"</span>, <span class="seriesInfo">STD 97</span>, <span class="seriesInfo">RFC 9110</span>, <span class="seriesInfo">DOI 10.17487/RFC9110</span>, <time datetime="2022-06" class="refDate">June 2022</time>, <span>&lt;<a href="https://www.rfc-editor.org/rfc/rfc9110">https://www.rfc-editor.org/rfc/rfc9110</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC9562">[RFC9562]</dt>
<dd>
<span class="refAuthor">Davis, K.</span>, <span class="refAuthor">Peabody, B.</span>, and <span class="refAuthor">P. Leach</span>, <span class="refTitle">"Universally Unique IDentifiers (UUIDs)"</span>, <span class="seriesInfo">RFC 9562</span>, <span class="seriesInfo">DOI 10.17487/RFC9562</span>, <time datetime="2024-05" class="refDate">May 2024</time>, <span>&lt;<a href="https://www.rfc-editor.org/rfc/rfc9562">https://www.rfc-editor.org/rfc/rfc9562</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
</div>
<div id="sec-informative-references">
<section id="section-11.2">
<h3 id="name-informative-references">
<a href="#section-11.2" class="section-number selfRef">11.2. </a><a href="#name-informative-references" class="section-name selfRef">Informative References</a>
</h3>
<dl class="references">
<dt id="I-D.ietf-oauth-transaction-tokens">[I-D.ietf-oauth-transaction-tokens]</dt>
<dd>
<span class="refAuthor">Tulshibagwale, A.</span>, <span class="refAuthor">Fletcher, G.</span>, and <span class="refAuthor">P. Kasselman</span>, <span class="refTitle">"Transaction Tokens"</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-ietf-oauth-transaction-tokens-07</span>, <time datetime="2026-01-24" class="refDate">24 January 2026</time>, <span>&lt;<a href="https://datatracker.ietf.org/doc/html/draft-ietf-oauth-transaction-tokens-07">https://datatracker.ietf.org/doc/html/draft-ietf-oauth-transaction-tokens-07</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="I-D.ietf-scitt-architecture">[I-D.ietf-scitt-architecture]</dt>
<dd>
<span class="refAuthor">Birkholz, H.</span>, <span class="refAuthor">Delignat-Lavaud, A.</span>, <span class="refAuthor">Fournet, C.</span>, <span class="refAuthor">Deshpande, Y.</span>, and <span class="refAuthor">S. Lasker</span>, <span class="refTitle">"An Architecture for Trustworthy and Transparent Digital Supply Chains"</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-ietf-scitt-architecture-22</span>, <time datetime="2025-10-10" class="refDate">10 October 2025</time>, <span>&lt;<a href="https://datatracker.ietf.org/doc/html/draft-ietf-scitt-architecture-22">https://datatracker.ietf.org/doc/html/draft-ietf-scitt-architecture-22</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="I-D.oauth-transaction-tokens-for-agents">[I-D.oauth-transaction-tokens-for-agents]</dt>
<dd>
<span class="refAuthor">Raut, A.</span>, <span class="refTitle">"Transaction Tokens For Agents"</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-oauth-transaction-tokens-for-agents-04</span>, <time datetime="2026-02-10" class="refDate">10 February 2026</time>, <span>&lt;<a href="https://datatracker.ietf.org/doc/html/draft-oauth-transaction-tokens-for-agents-04">https://datatracker.ietf.org/doc/html/draft-oauth-transaction-tokens-for-agents-04</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="OPENTELEMETRY">[OPENTELEMETRY]</dt>
<dd>
<span class="refAuthor">Cloud Native Computing Foundation</span>, <span class="refTitle">"OpenTelemetry Specification"</span>, <span>&lt;<a href="https://opentelemetry.io/docs/specs/otel/">https://opentelemetry.io/docs/specs/otel/</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8693">[RFC8693]</dt>
<dd>
<span class="refAuthor">Jones, M.</span>, <span class="refAuthor">Nadalin, A.</span>, <span class="refAuthor">Campbell, B., Ed.</span>, <span class="refAuthor">Bradley, J.</span>, and <span class="refAuthor">C. Mortimore</span>, <span class="refTitle">"OAuth 2.0 Token Exchange"</span>, <span class="seriesInfo">RFC 8693</span>, <span class="seriesInfo">DOI 10.17487/RFC8693</span>, <time datetime="2020-01" class="refDate">January 2020</time>, <span>&lt;<a href="https://www.rfc-editor.org/rfc/rfc8693">https://www.rfc-editor.org/rfc/rfc8693</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC9449">[RFC9449]</dt>
<dd>
<span class="refAuthor">Fett, D.</span>, <span class="refAuthor">Campbell, B.</span>, <span class="refAuthor">Bradley, J.</span>, <span class="refAuthor">Lodderstedt, T.</span>, <span class="refAuthor">Jones, M.</span>, and <span class="refAuthor">D. Waite</span>, <span class="refTitle">"OAuth 2.0 Demonstrating Proof of Possession (DPoP)"</span>, <span class="seriesInfo">RFC 9449</span>, <span class="seriesInfo">DOI 10.17487/RFC9449</span>, <time datetime="2023-09" class="refDate">September 2023</time>, <span>&lt;<a href="https://www.rfc-editor.org/rfc/rfc9449">https://www.rfc-editor.org/rfc/rfc9449</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="SPIFFE">[SPIFFE]</dt>
<dd>
<span class="refTitle">"Secure Production Identity Framework for Everyone (SPIFFE)"</span>, <span>&lt;<a href="https://spiffe.io/docs/latest/spiffe-about/overview/">https://spiffe.io/docs/latest/spiffe-about/overview/</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
</div>
</section>
</div>
<div id="use-cases">
<section id="appendix-A">
<h2 id="name-use-cases">
<a href="#name-use-cases" class="section-name selfRef">Use Cases</a>
</h2>
<p id="appendix-A-1">This section describes a representative use case demonstrating how
ECTs provide structured execution records.<a href="#appendix-A-1" class="pilcrow"></a></p>
<p id="appendix-A-2">Note: task identifiers in this section are abbreviated for
readability. In production, all "jti" values are required to be
UUIDs per <a href="#exec-claims" class="auto internal xref">Section 3.2.2</a>.<a href="#appendix-A-2" class="pilcrow"></a></p>
<div id="cross-organization-financial-trading">
<section id="appendix-A.1">
<h3 id="name-cross-organization-financia">
<a href="#name-cross-organization-financia" class="section-name selfRef">Cross-Organization Financial Trading</a>
</h3>
<p id="appendix-A.1-1">In a cross-organization trading workflow, an investment bank's
agents coordinate with an external credit rating agency. The
agents operate in separate trust domains with a federation
relationship. The DAG records that independent assessments from
both organizations were completed before trade execution.<a href="#appendix-A.1-1" class="pilcrow"></a></p>
<span id="name-cross-organization-trading-"></span><div id="fig-finance">
<figure id="figure-4">
<div class="alignLeft art-text artwork" id="appendix-A.1-2.1">
<pre>
Trust Domain: bank.example
Agent A1 (Portfolio Risk):
jti: task-001 par: []
iss: spiffe://bank.example/agent/risk
exec_act: analyze_portfolio_risk
Trust Domain: ratings.example (external)
Agent B1 (Credit Rating):
jti: task-002 par: []
iss: spiffe://ratings.example/agent/credit
exec_act: assess_credit_rating
Trust Domain: bank.example
Agent A2 (Compliance):
jti: task-003 par: [task-001, task-002]
iss: spiffe://bank.example/agent/compliance
exec_act: verify_trade_compliance
Agent A3 (Execution):
jti: task-004 par: [task-003]
iss: spiffe://bank.example/agent/execution
exec_act: execute_trade
</pre>
</div>
<figcaption><a href="#figure-4" class="selfRef">Figure 4</a>:
<a href="#name-cross-organization-trading-" class="selfRef">Cross-Organization Trading Workflow</a>
</figcaption></figure>
</div>
<p id="appendix-A.1-3">The resulting DAG:<a href="#appendix-A.1-3" class="pilcrow"></a></p>
<span id="name-cross-organization-dag"></span><div id="fig-finance-dag">
<figure id="figure-5">
<div class="alignLeft art-text artwork" id="appendix-A.1-4.1">
<pre>
task-001 (analyze_portfolio_risk) task-002 (assess_credit_rating)
[bank.example] [ratings.example]
\ /
v v
task-003 (verify_trade_compliance)
[bank.example]
|
v
task-004 (execute_trade)
[bank.example]
</pre>
</div>
<figcaption><a href="#figure-5" class="selfRef">Figure 5</a>:
<a href="#name-cross-organization-dag" class="selfRef">Cross-Organization DAG</a>
</figcaption></figure>
</div>
<p id="appendix-A.1-5">Task 003 has two parents from different trust domains,
demonstrating cross-organizational fan-in. The compliance agent
verifies both parent ECTs — one signed by a local key and one by
a federated key from the rating agency's trust domain.<a href="#appendix-A.1-5" class="pilcrow"></a></p>
</section>
</div>
</section>
</div>
<div id="related-work">
<section id="appendix-B">
<h2 id="name-related-work">
<a href="#name-related-work" class="section-name selfRef">Related Work</a>
</h2>
<div id="wimse-workload-identity">
<section id="appendix-B.1">
<h3 id="name-wimse-workload-identity">
<a href="#name-wimse-workload-identity" class="section-name selfRef">WIMSE Workload Identity</a>
</h3>
<p id="appendix-B.1-1">The WIMSE architecture <span>[<a href="#I-D.ietf-wimse-arch" class="cite xref">I-D.ietf-wimse-arch</a>]</span> and service-to-
service protocol <span>[<a href="#I-D.ietf-wimse-s2s-protocol" class="cite xref">I-D.ietf-wimse-s2s-protocol</a>]</span> provide the
identity foundation upon which ECTs are built. WIT/WPT answer
"who is this agent?" and "does it control the claimed key?" while
ECTs record "what did this agent do?" Together they form an
identity-plus-accountability framework for regulated agentic
systems.<a href="#appendix-B.1-1" class="pilcrow"></a></p>
</section>
</div>
<div id="oauth-20-token-exchange-and-the-act-claim">
<section id="appendix-B.2">
<h3 id="name-oauth-20-token-exchange-and">
<a href="#name-oauth-20-token-exchange-and" class="section-name selfRef">OAuth 2.0 Token Exchange and the "act" Claim</a>
</h3>
<p id="appendix-B.2-1"><span>[<a href="#RFC8693" class="cite xref">RFC8693</a>]</span> defines the OAuth 2.0 Token Exchange protocol and
registers the "act" (Actor) claim in the JWT Claims registry.
The "act" claim creates nested JSON objects representing a
delegation chain: "who is acting on behalf of whom." While
the nesting superficially resembles a chain, it is strictly
linear (each "act" object contains at most one nested "act"),
represents authorization delegation rather than task execution,
and carries no task identifiers or input/output integrity
data. The "act" chain cannot represent
branching (fan-out) or convergence (fan-in) and therefore
cannot form a DAG.<a href="#appendix-B.2-1" class="pilcrow"></a></p>
<p id="appendix-B.2-2">ECTs intentionally use the distinct claim name "exec_act" for the
action/task type to avoid collision with the "act" claim. The
two concepts are orthogonal: "act" records "who authorized whom,"
ECTs record "what was done, in what order."<a href="#appendix-B.2-2" class="pilcrow"></a></p>
</section>
</div>
<div id="transaction-tokens">
<section id="appendix-B.3">
<h3 id="name-transaction-tokens">
<a href="#name-transaction-tokens" class="section-name selfRef">Transaction Tokens</a>
</h3>
<p id="appendix-B.3-1">OAuth Transaction Tokens <span>[<a href="#I-D.ietf-oauth-transaction-tokens" class="cite xref">I-D.ietf-oauth-transaction-tokens</a>]</span>
propagate authorization context across workload call chains.
The Txn-Token "req_wl" claim accumulates a comma-separated list
of workloads that requested replacement tokens, which is the
closest existing mechanism to call-chain recording.<a href="#appendix-B.3-1" class="pilcrow"></a></p>
<p id="appendix-B.3-2">However, "req_wl" cannot form a DAG because:<a href="#appendix-B.3-2" class="pilcrow"></a></p>
<ul class="normal">
<li class="normal" id="appendix-B.3-3.1">
<p id="appendix-B.3-3.1.1">It is linear: a comma-separated string with no branching or
merging representation. When a workload fans out to multiple
downstream services, each receives the same "req_wl" value and
the branching is invisible.<a href="#appendix-B.3-3.1.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="appendix-B.3-3.2">
<p id="appendix-B.3-3.2.1">It is incomplete: only workloads that request a replacement
token from the Transaction Token Service appear in "req_wl";
workloads that forward the token unchanged are not recorded.<a href="#appendix-B.3-3.2.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="appendix-B.3-3.3">
<p id="appendix-B.3-3.3.1">It carries no task-level granularity, no parent references,
and no execution content.<a href="#appendix-B.3-3.3.1" class="pilcrow"></a></p>
</li>
<li class="normal" id="appendix-B.3-3.4">
<p id="appendix-B.3-3.4.1">It cannot represent convergence (fan-in): when two independent
paths must both complete before a dependent task proceeds, a
linear "req_wl" string cannot express that relationship.<a href="#appendix-B.3-3.4.1" class="pilcrow"></a></p>
</li>
</ul>
<p id="appendix-B.3-4">Extensions for agentic use cases
(<span>[<a href="#I-D.oauth-transaction-tokens-for-agents" class="cite xref">I-D.oauth-transaction-tokens-for-agents</a>]</span>) add agent
identity and constraints ("agentic_ctx") but no execution
ordering or DAG structure.<a href="#appendix-B.3-4" class="pilcrow"></a></p>
<p id="appendix-B.3-5">ECTs and Transaction Tokens are complementary: a Txn-Token
propagates authorization context ("this request is authorized
for scope X on behalf of user Y"), while an ECT records
execution accountability ("task T was performed, depending on
tasks P1 and P2"). An
agent request could carry both a Txn-Token for authorization
and an ECT for execution recording. The WPT "tth" claim
defined in <span>[<a href="#I-D.ietf-wimse-s2s-protocol" class="cite xref">I-D.ietf-wimse-s2s-protocol</a>]</span> can hash-bind a
WPT to a co-present Txn-Token; a similar binding mechanism
for ECTs is a potential future extension.<a href="#appendix-B.3-5" class="pilcrow"></a></p>
</section>
</div>
<div id="distributed-tracing-opentelemetry">
<section id="appendix-B.4">
<h3 id="name-distributed-tracing-opentel">
<a href="#name-distributed-tracing-opentel" class="section-name selfRef">Distributed Tracing (OpenTelemetry)</a>
</h3>
<p id="appendix-B.4-1">OpenTelemetry <span>[<a href="#OPENTELEMETRY" class="cite xref">OPENTELEMETRY</a>]</span> and similar distributed tracing
systems provide observability for debugging and monitoring. ECTs
differ in several important ways: ECTs are cryptographically
signed per-task with the agent's private key; ECTs are
tamper-evident through JWS signatures; ECTs enforce DAG validation
rules; and ECTs are designed for regulatory audit rather than
operational monitoring. OpenTelemetry data is typically controlled
by the platform operator and can be modified or deleted without
detection. ECTs and distributed traces are complementary: traces
provide observability while ECTs provide signed execution records.
ECTs may reference OpenTelemetry trace identifiers in the "ext"
claim for correlation.<a href="#appendix-B.4-1" class="pilcrow"></a></p>
</section>
</div>
<div id="w3c-provenance-data-model-prov">
<section id="appendix-B.5">
<h3 id="name-w3c-provenance-data-model-p">
<a href="#name-w3c-provenance-data-model-p" class="section-name selfRef">W3C Provenance Data Model (PROV)</a>
</h3>
<p id="appendix-B.5-1">The W3C PROV Data Model defines an Entity-Activity-Agent ontology
for representing provenance information. PROV's concepts map
closely to ECT structures: PROV Activities correspond to ECT
tasks, PROV Agents correspond to WIMSE workloads, and PROV's
"wasInformedBy" relation corresponds to ECT "par" references.
However, PROV uses RDF/OWL ontologies designed for post-hoc
documentation, while ECTs are runtime-embeddable JWT tokens with
cryptographic signatures. ECT audit data could be exported to
PROV format for interoperability with provenance-aware systems.<a href="#appendix-B.5-1" class="pilcrow"></a></p>
</section>
</div>
<div id="scitt-supply-chain-integrity-transparency-and-trust">
<section id="appendix-B.6">
<h3 id="name-scitt-supply-chain-integrit">
<a href="#name-scitt-supply-chain-integrit" class="section-name selfRef">SCITT (Supply Chain Integrity, Transparency, and Trust)</a>
</h3>
<p id="appendix-B.6-1">The SCITT architecture <span>[<a href="#I-D.ietf-scitt-architecture" class="cite xref">I-D.ietf-scitt-architecture</a>]</span> defines a
framework for transparent and auditable supply chain records.
ECTs and SCITT are complementary: the ECT "wid" claim can serve
as a correlation identifier in SCITT Signed Statements, linking
an ECT audit trail to a supply chain transparency record.<a href="#appendix-B.6-1" class="pilcrow"></a></p>
</section>
</div>
</section>
</div>
<div id="acknowledgments">
<section id="appendix-C">
<h2 id="name-acknowledgments">
<a href="#name-acknowledgments" class="section-name selfRef">Acknowledgments</a>
</h2>
<p id="appendix-C-1">The author thanks the WIMSE working group for their foundational
work on workload identity in multi-system environments. The
concepts of Workload Identity Tokens and Workload Proof Tokens
provide the identity foundation upon which execution context
tracing is built.<a href="#appendix-C-1" class="pilcrow"></a></p>
</section>
</div>
<div id="authors-addresses">
<section id="appendix-D">
<h2 id="name-authors-address">
<a href="#name-authors-address" class="section-name selfRef">Author's Address</a>
</h2>
<address class="vcard">
<div dir="auto" class="left"><span class="fn nameRole">Christian Nennemann</span></div>
<div dir="auto" class="left"><span class="org">Independent Researcher</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:ietf@nennemann.de" class="email">ietf@nennemann.de</a>
</div>
</address>
</section>
</div>
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