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Internet-DraftWIMSE Execution ContextFebruary 2026
NennemannExpires 28 August 2026[Page]
+
+
+
+
Workgroup:
+
Network Working Group
+
Internet-Draft:
+
draft-nennemann-wimse-execution-context-00
+
Published:
+
+ +
+
Intended Status:
+
Standards Track
+
Expires:
+
+
Author:
+
+
+
C. Nennemann
+
Independent Researcher
+
+
+
+
+

Execution Context Tokens for Distributed Agentic Workflows

+
+

Abstract

+

This document defines Execution Context Tokens (ECTs), an extension +to the Workload Identity in Multi System Environments (WIMSE) +architecture for distributed agentic workflows in regulated +environments. ECTs provide cryptographic proof of task execution +order, policy enforcement decisions, and compliance state across +agent-to-agent communication. By extending WIMSE Workload Identity +Tokens with execution context claims in JSON Web Token (JWT) +format, this specification enables regulated systems to maintain +structured audit trails that support compliance verification. +ECTs use a directed acyclic graph (DAG) structure to represent task +dependencies, record policy evaluation outcomes at each decision +point, and integrate with WIMSE Workload Identity Tokens (WIT) and +Workload Proof Tokens (WPT) using the same signing model and +cryptographic primitives. A new HTTP header field, +Execution-Context, is defined for transporting ECTs alongside +existing WIMSE headers. ECTs are a technical building block that +supports, but does not by itself constitute, compliance with +regulatory frameworks.

+
+
+
+

+Status of This Memo +

+

+ This Internet-Draft is submitted in full conformance with the + provisions of BCP 78 and BCP 79.

+

+ 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 https://datatracker.ietf.org/drafts/current/.

+

+ 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."

+

+ This Internet-Draft will expire on 28 August 2026.

+
+
+ +
+
+ ▲

+Table of Contents +

+ +
+
+
+
+

+1. Introduction +

+
+
+

+1.1. Motivation +

+

The Workload Identity in Multi System Environments (WIMSE) +framework [I-D.ietf-wimse-arch] provides robust workload +authentication through Workload Identity Tokens (WIT) and Workload +Proof Tokens (WPT). The WIMSE service-to-service protocol +[I-D.ietf-wimse-s2s-protocol] defines how workloads authenticate +each other across call chains using the Workload-Identity and +Workload-Proof-Token HTTP headers.

+

However, workload identity alone does not address execution +accountability. Knowing who performed an action does not prove +what was done, what policy was applied, or whether compliance +requirements were satisfied at each decision point.

+

Regulated environments increasingly deploy autonomous agents that +coordinate across organizational boundaries. Multiple regulatory +frameworks motivate the need for structured execution records:

+
    +
  • +

    The EU Artificial Intelligence Act [EU-AI-ACT] Article 12 +requires high-risk AI systems to be designed with capabilities +enabling automatic recording of events ("logs") while the +system is operating.

    +
    • +
  • +

    The U.S. FDA 21 CFR Part 11 [FDA-21CFR11] requires +computer-generated, timestamped audit trails that independently +record the date, time, operator identity, and actions taken +(Section 11.10(e)).

    +
    • +
  • +

    The Markets in Financial Instruments Directive (MiFID II) +[MIFID-II] requires firms to maintain records of transactions +and orders that are sufficient to enable supervisory authorities +to monitor compliance.

    +
    • +
  • +

    The Digital Operational Resilience Act (DORA) [DORA] Article 12 +requires financial entities to have logging policies that record +ICT activities and anomalies.

    +
    • +
+

This document defines an extension to the WIMSE architecture that +addresses the gap between workload identity and execution +accountability. WIMSE authenticates agents; this extension records +what they did, in what order, and what policy was evaluated.

+

As identified in [I-D.ni-wimse-ai-agent-identity], call context +in agentic workflows must always be visible and preserved. ECTs +provide a mechanism to address this requirement with cryptographic +assurances.

+
+
+
+
+

+1.2. Problem Statement +

+

Three core gaps exist in current approaches to regulated agentic +systems:

+
    +
  1. +

    WIMSE authenticates agents but does not record what they +actually did. A WIT proves "Agent A is authorized" but not +"Agent A executed Task X, under Policy Y, producing Output Z."

    +
    2. +
  2. +

    No standard mechanism exists to record policy evaluation +outcomes at each decision point in a multi-agent workflow.

    +
    3. +
  3. +

    No mechanism exists to cryptographically link compensation and +rollback decisions to original actions.

    +
    4. +
+

Existing observability tools such as distributed tracing +[OPENTELEMETRY] provide visibility for debugging and monitoring +but do not provide cryptographic assurances. Tracing data is not +cryptographically signed, not tamper-evident, and not designed for +regulatory audit scenarios.

+
+
+
+
+

+1.3. Scope and Applicability +

+

This document defines:

+
    +
  • +

    The Execution Context Token (ECT) format (Section 4)

    +
    • +
  • +

    DAG structure for task dependency ordering (Section 6)

    +
    • +
  • +

    Policy checkpoint recording (Section 4.2.3)

    +
    • +
  • +

    Integration with the WIMSE identity framework +(Section 3)

    +
    • +
  • +

    An HTTP header for ECT transport (Section 5)

    +
    • +
  • +

    Audit ledger interface requirements (Section 8)

    +
    • +
+

The following are out of scope and are handled by WIMSE:

+
    +
  • +

    Workload authentication and identity provisioning

    +
    • +
  • +

    Key distribution and management

    +
    • +
  • +

    Trust domain establishment and management

    +
    • +
  • +

    Credential lifecycle management

    +
    • +
+
+
+
+
+

+1.4. Relationship to Regulatory Compliance +

+

ECTs are a technical mechanism that can support compliance programs +by providing structured, cryptographically signed execution +records. ECTs do not by themselves constitute compliance with any +regulatory framework referenced in this document.

+

Compliance with each referenced regulation requires organizational +controls, policies, procedures, validation, and governance measures +beyond the scope of this specification. The regulatory references +in this document are intended to motivate the design requirements, +not to claim that implementing ECTs satisfies these regulations.

+

ECTs provide evidence of claimed execution ordering and policy +evaluation. They do not independently verify that the claimed +execution actually occurred as described, that the policy +evaluation was correct, or that the agent faithfully performed the +stated action. The trustworthiness of ECT claims depends on the +trustworthiness of the signing agent and the integrity of the +broader deployment environment.

+
+
+
+
+
+
+

+2. Conventions and Definitions +

+

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", +"MAY", and "OPTIONAL" in this document are to be interpreted as +described in BCP 14 [RFC2119] [RFC8174] when, and only when, they +appear in all capitals, as shown here.

+

The following terms are used in this document:

+
+
Agent:
+
+

An autonomous workload, as defined by WIMSE +[I-D.ietf-wimse-arch], that executes tasks within a workflow.

+
+
+
Task:
+
+

A discrete unit of agent work that consumes inputs and produces +outputs.

+
+
+
Directed Acyclic Graph (DAG):
+
+

A graph structure representing task dependency ordering where +edges are directed and no cycles exist.

+
+
+
Execution Context Token (ECT):
+
+

A JSON Web Token [RFC7519] defined by this specification that +records task execution details and policy evaluation outcomes.

+
+
+
Audit Ledger:
+
+

An append-only, immutable log of all ECTs within a workflow or +set of workflows, used for regulatory audit and compliance +verification.

+
+
+
Policy Checkpoint:
+
+

A point in a workflow where a policy evaluation outcome is +recorded within an ECT.

+
+
+
Workload Identity Token (WIT):
+
+

A WIMSE credential proving a workload's identity within a trust +domain.

+
+
+
Workload Proof Token (WPT):
+
+

A WIMSE proof-of-possession token used for request-level +authentication.

+
+
+
Trust Domain:
+
+

A WIMSE concept representing an organizational boundary with a +shared identity issuer, corresponding to a SPIFFE [SPIFFE] +trust domain.

+
+
+
Witness:
+
+

A third-party entity that observes and attests to the execution +of a task, providing additional accountability.

+
+
+
+
+
+
+
+

+3. WIMSE Architecture Integration +

+
+
+

+3.1. WIMSE Foundation +

+

The WIMSE architecture [I-D.ietf-wimse-arch] defines:

+
    +
  • +

    Workload Identity Tokens (WIT) that prove a workload's identity +within a trust domain ("I am Agent X in trust domain Y")

    +
    • +
  • +

    Workload Proof Tokens (WPT) that prove possession of the private +key associated with a WIT ("I control the key for Agent X")

    +
    • +
  • +

    Multi-hop authentication via the service-to-service protocol +[I-D.ietf-wimse-s2s-protocol]

    +
    • +
+

The following execution accountability needs are complementary to +the WIMSE scope and are not addressed by workload identity alone:

+
    +
  • +

    Recording what agents actually do with their authenticated +identity

    +
    • +
  • +

    Recording policy evaluation outcomes at each hop

    +
    • +
  • +

    Maintaining structured execution records

    +
    • +
  • +

    Linking compensation or rollback actions to original tasks

    +
    • +
+
+
+
+
+

+3.2. Extension Model +

+

ECTs extend WIMSE by adding an execution accountability layer +between the identity layer and the application layer:

+
+
+
+
++--------------------------------------------------+
+|  WIMSE Layer (Identity)                          |
+|    WIT: "I am Agent X (spiffe://td/agent/x)"    |
+|    WPT: "I prove I control the key for Agent X"  |
++--------------------------------------------------+
+                       |
+                       v
++--------------------------------------------------+
+|  ECT Layer (Execution Accountability) [This Spec]|
+|    ECT: "Task executed, dependencies met,        |
+|          policy evaluated, outcome recorded"      |
++--------------------------------------------------+
+                       |
+                       v
++--------------------------------------------------+
+|  Ledger Layer (Immutable Record)                 |
+|    "All ECTs appended to audit ledger"           |
++--------------------------------------------------+
+
+
+
Figure 1: +WIMSE Extension Architecture Layers +
+
+

This extension reuses the WIMSE signing model, extends JWT claims +using standard JWT extensibility [RFC7519], and maintains WIMSE +concepts including trust domains and workload identifiers.

+
+
+
+
+

+3.3. Integration Points +

+

An ECT integrates with the WIMSE identity framework through the +following mechanisms:

+
    +
  • +

    The ECT JOSE header "kid" parameter MUST reference the public +key identifier from the agent's WIT.

    +
    • +
  • +

    The ECT "iss" claim MUST use the WIMSE workload identifier +format (a SPIFFE ID [SPIFFE]).

    +
    • +
  • +

    The ECT MUST be signed with the same private key used to +generate the agent's WPT.

    +
    • +
  • +

    The ECT signing algorithm (JOSE header "alg" parameter) MUST +match the algorithm used in the corresponding WIT.

    +
    • +
+

When an agent makes an HTTP request to another agent, the three +tokens are carried in their respective HTTP header fields:

+
+
+
+
+HTTP Request from Agent A to Agent B:
+  Workload-Identity:    <WIT for Agent A>
+  Workload-Proof-Token: <WPT proving A controls key>
+  Execution-Context:    <ECT recording what A did>
+
+
+
Figure 2: +HTTP Header Stacking +
+
+

The receiving agent (Agent B) verifies in order:

+
    +
  1. +

    WIT and WPT (WIMSE layer): Proves who Agent A is and that the +request is authentic.

    +
    2. +
  2. +

    ECT (this extension): Records what Agent A did, what policy was +evaluated, and what precedent tasks exist.

    +
    3. +
  3. +

    Ledger: Appends the verified ECT to the audit ledger.

    +
    4. +
+
+
+
+
+
+
+

+4. Execution Context Token Format +

+

An Execution Context Token is a JSON Web Token (JWT) [RFC7519] +signed as a JSON Web Signature (JWS) [RFC7515] using the Compact +Serialization. JWS JSON Serialization MUST NOT be used for ECTs.

+
+
+

+4.1. JOSE Header +

+

The ECT JOSE header MUST contain the following parameters:

+
+
+
+
+{
+  "alg": "ES256",
+  "typ": "wimse-exec+jwt",
+  "kid": "agent-a-key-id-123"
+}
+
+
+
Figure 3: +ECT JOSE Header Example +
+
+
+
alg:
+
+

REQUIRED. The digital signature algorithm used to sign the ECT. +MUST match the algorithm in the corresponding WIT. +Implementations MUST support ES256 [RFC7518]. The "alg" +value MUST NOT be "none". Symmetric algorithms (e.g., HS256, +HS384, HS512) MUST NOT be used, as ECTs require asymmetric +signatures for non-repudiation.

+
+
+
typ:
+
+

REQUIRED. MUST be set to "wimse-exec+jwt" to distinguish ECTs +from other JWT types, consistent with the WIMSE convention for +type parameter values.

+
+
+
kid:
+
+

REQUIRED. The key identifier referencing the public key from +the agent's WIT [RFC7517]. Used by verifiers to look up the +correct public key for signature verification.

+
+
+
+
+
+
+
+

+4.2. JWT Claims +

+

The ECT payload contains both WIMSE-compatible standard JWT claims +and execution context claims defined by this specification.

+
+
+

+4.2.1. WIMSE-Compatible Claims +

+

The following standard JWT claims [RFC7519] MUST be present in +every ECT:

+
+
iss:
+
+

REQUIRED. StringOrURI. The issuer of the ECT, which MUST be +the workload's SPIFFE ID in the format +spiffe://<trust-domain>/<path>. This MUST match the "sub" +claim of the agent's WIT.

+
+
+
sub:
+
+

OPTIONAL. StringOrURI. The subject of the ECT. When present, +MUST equal the "iss" claim.

+
+
+
aud:
+
+

REQUIRED. StringOrURI or array of StringOrURI. The intended +recipient(s) of the ECT. Typically the next agent in the +workflow or the ledger endpoint.

+
+
+
iat:
+
+

REQUIRED. NumericDate. The time at which the ECT was issued. +The ECT records a completed action, so the "iat" value reflects +when the record was created, not when task execution began.

+
+
+
exp:
+
+

REQUIRED. NumericDate. The expiration time of the ECT. +Implementations SHOULD set this to 5 to 15 minutes after "iat" +to limit the replay window while allowing for reasonable clock +skew and processing time.

+
+
+
jti:
+
+

OPTIONAL. String. A unique identifier for the ECT, useful for +additional replay detection.

+
+
+
+
+
+
+
+

+4.2.2. Execution Context Claims +

+

The following claims are defined by this specification:

+
+
wid:
+
+

OPTIONAL. String. A workflow identifier that groups related +ECTs into a single workflow. When present, MUST be a UUID +[RFC9562]. When absent, the "tid" uniqueness requirement +applies globally across the entire ledger.

+
+
+
tid:
+
+

REQUIRED. String. A globally unique task identifier in UUID +format [RFC9562]. Each task MUST have a unique "tid" value. +When "wid" is present, uniqueness is scoped to the workflow; +when "wid" is absent, uniqueness MUST be enforced globally +across the ledger.

+
+
+
exec_act:
+
+

REQUIRED. String. The action or task type identifier describing +what the agent performed (e.g., "process_payment", +"validate_safety", "calculate_dosage"). Note: this claim is +intentionally named "exec_act" rather than "act" to avoid +collision with the "act" (Actor) claim registered by +[RFC8693].

+
+
+
par:
+
+

REQUIRED. Array of strings. Parent task identifiers +representing DAG dependencies. Each element MUST be a valid +"tid" from a previously executed task. An empty array indicates +a root task with no dependencies. A workflow MAY contain +multiple root tasks.

+
+
+
+
+
+
+
+

+4.2.3. Policy Claims +

+

The following claims record policy evaluation outcomes:

+
+
pol:
+
+

REQUIRED. String. The identifier of the policy rule that was +evaluated for this task (e.g., +"clinical_data_access_policy_v1").

+
+
+
pol_decision:
+
+

REQUIRED. String. The result of the policy evaluation. MUST +be one of: "approved", "rejected", or "pending_human_review".

+
+
+
pol_enforcer:
+
+

OPTIONAL. StringOrURI. The identity of the entity (system or +person) that evaluated the policy decision. When present, +SHOULD use SPIFFE ID format.

+
+
+
pol_timestamp:
+
+

OPTIONAL. NumericDate. The time at which the policy decision +was made. When present, MUST be equal to or earlier than the +"iat" claim.

+
+
+
+
+
+
+
+

+4.2.4. Data Integrity Claims +

+

The following claims provide integrity verification for task +inputs and outputs without revealing the data itself:

+
+
inp_hash:
+
+

OPTIONAL. String. A cryptographic hash of the input data, +formatted as "hash-algorithm:base64url-encoded-hash" (e.g., +"sha-256:n4bQgYhMfWWaL-qgxVrQFaO_TxsrC4Is0V1sFbDwCgg"). The +hash algorithm identifier SHOULD be "sha-256". The hash MUST be +computed over the raw octets of the input data.

+
+
+
out_hash:
+
+

OPTIONAL. String. A cryptographic hash of the output data, +using the same format as "inp_hash".

+
+
+
inp_classification:
+
+

OPTIONAL. String. The data sensitivity classification of the +input (e.g., "public", "confidential", "restricted").

+
+
+
+
+
+
+
+

+4.2.5. Operational Claims +

+

The following claims provide additional operational context:

+
+
exec_time_ms:
+
+

OPTIONAL. Integer. The execution duration of the task in +milliseconds. MUST be a non-negative integer.

+
+
+
regulated_domain:
+
+

OPTIONAL. String. The regulatory domain applicable to this +task. Values are drawn from an extensible set; initial values +include "medtech", "finance", and "military".

+
+
+
model_version:
+
+

OPTIONAL. String. The version identifier of the AI or ML model +used to perform the task, if applicable.

+
+
+
+
+
+
+
+

+4.2.6. Witness Claims +

+
+
witnessed_by:
+
+

OPTIONAL. Array of StringOrURI. Identifiers of third-party +entities that observed or attested to the execution of this +task. When present, each element SHOULD use SPIFFE ID format. +In regulated environments, implementations SHOULD use witness +attestation for critical decision points to mitigate the risk +of single-agent false claims.

+
+
+
+
+
+
+
+

+4.2.7. Compensation Claims +

+
+
compensation_required:
+
+

OPTIONAL. Boolean. Indicates whether this task is a +compensation or rollback action for a previous task.

+
+
+
compensation_reason:
+
+

OPTIONAL. String. A human-readable reason for the compensation +action. MUST be present if "compensation_required" is true.

+
+
+
+

Note: compensation ECTs reference historical parent tasks via the +"par" claim. The referenced parent ECTs may have passed their own +"exp" time; ECT expiration applies to the verification window of +the ECT itself, not to its validity as a parent reference in the +ledger.

+
+
+
+
+

+4.2.8. Extension Claims +

+
+
ext:
+
+

OPTIONAL. Object. An extension object for domain-specific +claims not defined by this specification. Implementations +that do not understand extension claims SHOULD ignore them. +To avoid key collisions between different domains, extension +key names SHOULD use reverse domain notation (e.g., +"com.example.custom_field").

+
+
+
+

The "ext" claim is a generic extension mechanism; it is not +registered in the IANA JWT Claims registry because its semantics +depend on the domain-specific claims within it.

+
+
+
+
+
+
+

+4.3. Complete ECT Example +

+

The following is a complete ECT payload example:

+
+
+
+
+{
+  "iss": "spiffe://example.com/agent/clinical",
+  "sub": "spiffe://example.com/agent/clinical",
+  "aud": "spiffe://example.com/agent/safety",
+  "iat": 1772064150,
+  "exp": 1772064750,
+
+  "wid": "a0b1c2d3-e4f5-6789-abcd-ef0123456789",
+  "tid": "550e8400-e29b-41d4-a716-446655440001",
+  "exec_act": "recommend_treatment",
+  "par": [],
+
+  "pol": "clinical_reasoning_policy_v2",
+  "pol_decision": "approved",
+  "pol_enforcer": "spiffe://example.com/policy/clinical-engine",
+  "pol_timestamp": 1772064145,
+
+  "inp_hash": "sha-256:n4bQgYhMfWWaL-qgxVrQFaO_TxsrC4Is0V1sFbDwCgg",
+  "out_hash": "sha-256:LCa0a2j_xo_5m0U8HTBBNBNCLXBkg7-g-YpeiGJm564",
+  "inp_classification": "confidential",
+  "exec_time_ms": 245,
+  "regulated_domain": "medtech",
+  "model_version": "clinical-reasoning-v4.2",
+
+  "witnessed_by": [
+    "spiffe://example.com/audit/observer-1"
+  ]
+}
+
+
+
Figure 4: +Complete ECT Payload Example +
+
+
+
+
+
+
+
+

+5. HTTP Header Transport +

+
+
+

+5.1. Execution-Context Header Field +

+

This specification defines the Execution-Context HTTP header field +[RFC9110] for transporting ECTs between agents.

+

The header field value is the ECT in JWS Compact Serialization +format [RFC7515]. The value consists of three Base64url-encoded +parts separated by period (".") characters.

+

An agent sending a request to another agent includes the +Execution-Context header alongside the WIMSE Workload-Identity +and Workload-Proof-Token headers:

+
+
+
+
+GET /api/safety-check HTTP/1.1
+Host: safety-agent.example.com
+Workload-Identity: eyJhbGci...WIT...
+Workload-Proof-Token: eyJhbGci...WPT...
+Execution-Context: eyJhbGci...ECT...
+
+
+
Figure 5: +HTTP Request with ECT Header +
+
+

When multiple parent tasks contribute context to a single request, +multiple Execution-Context header field lines MAY be included, each +carrying a separate ECT in JWS Compact Serialization format.

+
+
+
+
+
+
+

+6. DAG Validation +

+
+
+

+6.1. Overview +

+

ECTs form a Directed Acyclic Graph (DAG) where each task +references its parent tasks via the "par" claim. This structure +provides a cryptographically signed record of execution ordering, +enabling auditors to reconstruct the complete workflow and verify +that required predecessor tasks were recorded before dependent +tasks.

+
+
+
+
+

+6.2. Validation Rules +

+

When receiving and verifying an ECT, implementations MUST perform +the following DAG validation steps:

+
    +
  1. +

    Task ID Uniqueness: The "tid" claim MUST be unique within the +applicable scope (the workflow identified by "wid", or the +entire ledger if "wid" is absent). If a task with the same +"tid" already exists, the ECT MUST be rejected.

    +
    2. +
  2. +

    Parent Existence: Every task identifier listed in the "par" +array MUST correspond to a task that has been previously +recorded in the ledger. If any parent task is not found, the +ECT MUST be rejected.

    +
    3. +
  3. +

    Temporal Ordering: The "iat" value of every parent task MUST be +less than the "iat" value of the current task plus a +configurable clock skew tolerance (RECOMMENDED: 30 seconds). +If any parent task has an "iat" that violates this constraint, +the ECT MUST be rejected.

    +
    4. +
  4. +

    Acyclicity: Following the chain of parent references MUST NOT +lead back to the current task's "tid". If a cycle is detected, +the ECT MUST be rejected.

    +
    5. +
  5. +

    Trust Domain Consistency: Parent tasks SHOULD belong to the +same trust domain or to a trust domain with which a federation +relationship has been established.

    +
    6. +
+
+
+
+
+

+6.3. DAG Validation Algorithm +

+

The following pseudocode describes the DAG validation procedure:

+
+
+
+
+function validate_dag(ect, ledger, clock_skew_tolerance):
+  // Step 1: Uniqueness check
+  if ledger.contains(ect.tid, ect.wid):
+    return error("Task ID already exists in ledger")
+
+  // Step 2: Parent existence and temporal ordering
+  for parent_id in ect.par:
+    parent = ledger.get(parent_id)
+    if parent is null:
+      return error("Parent task not found: " + parent_id)
+    if parent.iat >= ect.iat + clock_skew_tolerance:
+      return error("Parent task not earlier than current")
+
+  // Step 3: Cycle detection
+  visited = set()
+  if has_cycle(ect.tid, ect.par, ledger, visited):
+    return error("Circular dependency detected")
+
+  return success
+
+function has_cycle(target_tid, parent_ids, ledger, visited):
+  for parent_id in parent_ids:
+    if parent_id == target_tid:
+      return true
+    if parent_id in visited:
+      continue
+    visited.add(parent_id)
+    parent = ledger.get(parent_id)
+    if parent is not null:
+      if has_cycle(target_tid, parent.par, ledger, visited):
+        return true
+  return false
+
+
+
Figure 6: +DAG Validation Pseudocode +
+
+

The cycle detection traverses the ancestor graph rooted at the +current task's parents. The complexity is O(V) where V is the +number of ancestor nodes reachable from the current task's parent +references. For typical workflows with shallow DAGs, this is +efficient. Implementations SHOULD cache cycle detection results +for previously verified tasks to avoid redundant traversals.

+
+
+
+
+
+
+

+7. Signature and Token Verification +

+
+
+

+7.1. Verification Procedure +

+

When an agent receives an ECT, it MUST perform the following +verification steps in order:

+
    +
  1. +

    Parse the JWS Compact Serialization to extract the JOSE header, +payload, and signature components per [RFC7515].

    +
    2. +
  2. +

    Verify that the "typ" header parameter is "wimse-exec+jwt".

    +
    3. +
  3. +

    Verify that the "alg" header parameter is not "none" and is +not a symmetric algorithm.

    +
    4. +
  4. +

    Verify the "kid" header parameter references a known, valid +public key from a WIT within the trust domain.

    +
    5. +
  5. +

    Retrieve the public key identified by "kid" and verify the JWS +signature per [RFC7515] Section 5.2.

    +
    6. +
  6. +

    Verify the "alg" header parameter matches the algorithm in the +corresponding WIT.

    +
    7. +
  7. +

    Verify the "iss" claim matches the "sub" claim of the WIT +associated with the "kid" public key.

    +
    8. +
  8. +

    Verify the "aud" claim contains the verifier's own workload +identity or an expected recipient identifier.

    +
    9. +
  9. +

    Verify the "exp" claim indicates the ECT has not expired.

    +
    10. +
  10. +

    Verify the "iat" claim is not unreasonably far in the past +(implementation-specific threshold, RECOMMENDED maximum of +15 minutes).

    +
    11. +
  11. +

    Verify all required claims ("tid", "exec_act", "par", "pol", +"pol_decision") are present and well-formed.

    +
    12. +
  12. +

    Verify "pol_decision" is one of "approved", "rejected", or +"pending_human_review".

    +
    13. +
  13. +

    Perform DAG validation per Section 6.

    +
    14. +
  14. +

    If all checks pass, the ECT MUST be appended to the audit +ledger.

    +
    15. +
+

If any verification step fails, the ECT MUST be rejected and the +failure MUST be logged for audit purposes. Error messages +SHOULD NOT reveal whether specific parent task IDs exist in the +ledger, to prevent information disclosure.

+
+
+
+
+

+7.2. Verification Pseudocode +

+
+
+
+
+function verify_ect(ect_jws, verifier_id,
+                     trust_domain_keys, ledger):
+  // Parse JWS
+  (header, payload, signature) = parse_jws(ect_jws)
+
+  // Verify header
+  if header.typ != "wimse-exec+jwt":
+    return reject("Invalid typ parameter")
+
+  if header.alg == "none" or is_symmetric(header.alg):
+    return reject("Prohibited algorithm")
+
+  // Look up public key
+  public_key = trust_domain_keys.get(header.kid)
+  if public_key is null:
+    return reject("Unknown key identifier")
+
+  // Verify signature
+  if not verify_jws_signature(header, payload,
+                               signature, public_key):
+    return reject("Invalid signature")
+
+  // Verify algorithm alignment
+  wit = get_wit_for_key(header.kid)
+  if header.alg != wit.alg:
+    return reject("Algorithm mismatch with WIT")
+
+  // Verify issuer matches WIT subject
+  if payload.iss != wit.sub:
+    return reject("Issuer does not match WIT subject")
+
+  // Verify audience
+  if verifier_id not in payload.aud:
+    return reject("ECT not intended for this recipient")
+
+  // Verify not expired
+  if payload.exp < current_time():
+    return reject("ECT has expired")
+
+  // Verify iat freshness
+  if payload.iat < current_time() - max_age_threshold:
+    return reject("ECT issued too long ago")
+
+  // Verify required claims
+  for claim in ["tid", "exec_act", "par",
+                 "pol", "pol_decision"]:
+    if claim not in payload:
+      return reject("Missing required claim: " + claim)
+
+  // Validate pol_decision value
+  if payload.pol_decision not in
+     ["approved", "rejected", "pending_human_review"]:
+    return reject("Invalid pol_decision value")
+
+  // Validate DAG
+  result = validate_dag(payload, ledger,
+                         clock_skew_tolerance)
+  if result is error:
+    return reject("DAG validation failed")
+
+  // All checks passed; append to ledger
+  ledger.append(payload)
+  return accept
+
+
+
Figure 7: +ECT Verification Pseudocode +
+
+
+
+
+
+
+
+

+8. Audit Ledger Interface +

+
+
+

+8.1. Overview +

+

ECTs are designed to be recorded in an immutable audit ledger for +compliance verification and post-hoc analysis. This specification +defines the logical interface for the ledger but does not mandate +a specific storage technology. Implementations MAY use +append-only logs, databases with cryptographic commitment schemes, +distributed ledgers, or any storage mechanism that provides the +required properties.

+
+
+
+
+

+8.2. Required Properties +

+

An audit ledger implementation MUST provide:

+
    +
  1. +

    Append-only semantics: Once an ECT is recorded, it MUST NOT be +modified or deleted.

    +
    2. +
  2. +

    Ordering: The ledger MUST maintain a total ordering of ECT +entries via a monotonically increasing sequence number.

    +
    3. +
  3. +

    Lookup by task ID: The ledger MUST support efficient retrieval +of ECT entries by "tid" value.

    +
    4. +
  4. +

    Integrity verification: The ledger SHOULD provide a mechanism +to verify that no entries have been tampered with (e.g., +hash chains or Merkle trees).

    +
    5. +
+

The ledger SHOULD be maintained by an entity independent of the +workflow agents to reduce the risk of collusion.

+
+
+
+
+

+8.3. Ledger Entry Structure +

+

Each ledger entry is a logical record containing:

+
+
+
+
+{
+  "ledger_sequence": 42,
+  "task_id": "550e8400-e29b-41d4-a716-446655440001",
+  "agent_id": "spiffe://example.com/agent/clinical",
+  "action": "recommend_treatment",
+  "parents": [],
+  "ect_jws": "eyJhbGciOiJFUzI1NiIs...<complete JWS>",
+  "signature_verified": true,
+  "verification_timestamp": "2026-02-24T15:42:31.000Z",
+  "stored_timestamp": "2026-02-24T15:42:31.050Z"
+}
+
+
+
Figure 8: +Ledger Entry Example +
+
+

The "ect_jws" field contains the full JWS Compact Serialization +and is the authoritative record. The other fields ("agent_id", +"action", "parents") are convenience indexes derived from the +ECT payload; if they disagree with the JWS payload, the JWS +payload takes precedence.

+
+
+
+
+
+
+

+9. Use Cases +

+

This section describes representative use cases demonstrating how +ECTs provide execution records in regulated environments. These +examples demonstrate ECT mechanics; production deployments would +include additional domain-specific requirements beyond the scope +of this specification.

+

Note: task identifiers in this section are abbreviated for +readability. In production, all "tid" values MUST be UUIDs per +[RFC9562].

+
+
+

+9.1. Medical Device SDLC Workflow +

+

In a medical device software development lifecycle (SDLC), +AI agents assist across multiple phases from requirements +analysis through release approval. Regulatory frameworks +including [FDA-21CFR11] Section 11.10(e) and [EU-MDR] require +audit trails documenting the complete development process for +software used in medical devices.

+
+
+
+
+Agent A (Spec Reviewer):
+  tid: task-001    par: []
+  exec_act: review_requirements_spec
+  pol: spec_review_policy_v2     pol_decision: approved
+
+Agent B (Code Generator):
+  tid: task-002    par: [task-001]
+  exec_act: implement_module
+  pol: coding_standards_v3       pol_decision: approved
+
+Agent C (Test Agent):
+  tid: task-003    par: [task-002]
+  exec_act: execute_test_suite
+  pol: test_coverage_policy_v1   pol_decision: approved
+
+Agent D (Build Agent):
+  tid: task-004    par: [task-003]
+  exec_act: build_release_artifact
+  pol: build_validation_v2       pol_decision: approved
+
+Human Release Manager:
+  tid: task-005    par: [task-004]
+  exec_act: approve_release
+  pol: release_approval_policy   pol_decision: approved
+  pol_enforcer: spiffe://meddev.example/human/release-mgr-42
+  witnessed_by: [spiffe://meddev.example/audit/qa-observer-1]
+
+
+
Figure 9: +Medical Device SDLC Workflow +
+
+

ECTs record that requirements were reviewed before implementation +began, that tests were executed against the implemented code, that +the build artifact was validated, and that a human release manager +explicitly approved the release. The DAG structure ensures no +phase was skipped or reordered.

+
+
+

+9.1.1. FDA Audit with DAG Reconstruction +

+

During a regulatory audit, an FDA reviewer requests evidence of +the development process for a specific software release. The +auditing authority retrieves all ECTs sharing the same workflow +identifier ("wid") from the audit ledger and reconstructs the +complete DAG:

+
+
+
+
+task-001 (review_requirements_spec)
+  |
+  v
+task-002 (implement_module)
+  |
+  v
+task-003 (execute_test_suite)
+  |
+  v
+task-004 (build_release_artifact)
+  |
+  v
+task-005 (approve_release) [human, witnessed]
+
+
+
Figure 10: +Reconstructed DAG for FDA Audit +
+
+

The reconstructed DAG provides cryptographic evidence that:

+
    +
  • +

    Each phase was executed by an identified and authenticated agent.

    +
    • +
  • +

    Policy checkpoints were evaluated at every phase transition.

    +
    • +
  • +

    The execution sequence was maintained (no step was bypassed).

    +
    • +
  • +

    A human-in-the-loop approved the final release, with independent +witness attestation.

    +
    • +
  • +

    Timestamps and execution durations are recorded for each step.

    +
    • +
+

This can contribute to compliance with:

+
    +
  • +

    [FDA-21CFR11] Section 11.10(e): Computer-generated audit trails +that record the date, time, and identity of the operator.

    +
    • +
  • +

    [EU-MDR] Annex II: Technical documentation traceability for the +software development lifecycle.

    +
    • +
  • +

    [EU-AI-ACT] Article 12: Automatic logging capabilities for +high-risk AI systems involved in the development process.

    +
    • +
  • +

    [EU-AI-ACT] Article 14: ECTs can record evidence that human +oversight events occurred during the release process.

    +
    • +
+
+
+
+
+
+
+

+9.2. Financial Trading Workflow +

+

In a financial trading workflow, agents perform risk assessment, +compliance verification, and trade execution. The DAG structure +records that compliance checks were evaluated before trade +execution.

+
+
+
+
+Agent A (Risk Assessment):
+  tid: task-001    par: []
+  exec_act: calculate_risk_exposure
+  pol: risk_limits_policy_v2  pol_decision: approved
+
+Agent B (Compliance):
+  tid: task-002    par: [task-001]
+  exec_act: verify_compliance
+  pol: compliance_check_v1    pol_decision: approved
+
+Agent C (Execution):
+  tid: task-003    par: [task-002]
+  exec_act: execute_trade
+  pol: execution_policy_v3    pol_decision: approved
+
+
+
Figure 11: +Financial Trading Workflow +
+
+

This can contribute to compliance with:

+
    +
  • +

    [MIFID-II]: ECTs provide cryptographic records of the execution +sequence that can support transaction audit requirements.

    +
    • +
  • +

    [DORA] Article 12: ECTs contribute to ICT activity logging.

    +
    • +
  • +

    [EU-AI-ACT] Article 12: Logging of decisions made by AI-driven +systems.

    +
    • +
+
+
+
+
+

+9.3. Compensation and Rollback +

+

When a compliance violation is discovered after execution, ECTs +provide a mechanism to record authorized compensation actions with +a cryptographic link to the original task:

+
+
+
+
+{
+  "iss": "spiffe://bank.com/agent/operations",
+  "sub": "spiffe://bank.com/agent/operations",
+  "aud": "spiffe://bank.com/system/ledger",
+  "iat": 1772150550,
+  "exp": 1772151150,
+  "wid": "d3e4f5a6-b7c8-9012-def0-123456789012",
+  "tid": "550e8400-e29b-41d4-a716-446655440099",
+  "exec_act": "initiate_trade_rollback",
+  "par": ["550e8400-e29b-41d4-a716-446655440003"],
+  "pol": "compensation_policy_v1",
+  "pol_decision": "approved",
+  "pol_enforcer": "spiffe://bank.com/human/compliance-officer",
+  "compensation_required": true,
+  "compensation_reason": "policy_violation_in_parent_trade"
+}
+
+
+
Figure 12: +Compensation ECT Example +
+
+

The "par" claim links the compensation action to the original +trade, creating an auditable chain from execution through +violation discovery to remediation.

+
+
+
+
+

+9.4. Autonomous Logistics Coordination +

+

In a logistics workflow, multiple compliance checks must complete +before shipment commitment. The DAG structure records that all +required checks were completed:

+
+
+
+
+Agent A (Route Planning):
+  tid: task-001    par: []
+  exec_act: plan_route
+  pol: route_policy_v1        pol_decision: approved
+
+Agent B (Customs):
+  tid: task-002    par: [task-001]
+  exec_act: validate_customs
+  pol: customs_policy_v2      pol_decision: approved
+
+Agent C (Safety):
+  tid: task-003    par: [task-001]
+  exec_act: verify_cargo_safety
+  pol: safety_policy_v1       pol_decision: approved
+
+Agent D (Payment):
+  tid: task-004    par: [task-002, task-003]
+  exec_act: authorize_payment
+  pol: payment_policy_v3      pol_decision: approved
+
+System (Commitment):
+  tid: task-005    par: [task-004]
+  exec_act: commit_shipment
+  pol: commitment_policy_v1   pol_decision: approved
+
+
+
Figure 13: +Logistics Workflow with Parallel Tasks +
+
+

Note that tasks 002 and 003 both depend only on task-001 and can +execute in parallel. Task 004 depends on both, demonstrating the +DAG's ability to represent parallel execution with a join point.

+
+
+
+
+
+
+

+10. Security Considerations +

+

This section addresses security considerations following the +guidance in [RFC3552].

+
+
+

+10.1. Threat Model +

+

The following threat actors are considered:

+
    +
  • +

    Malicious agent (insider threat): An agent within the trust +domain that intentionally creates false ECT claims.

    +
    • +
  • +

    Compromised agent (external attacker): An agent whose private +key has been obtained by an external attacker.

    +
    • +
  • +

    Ledger tamperer: An entity attempting to modify or delete ledger +entries after they have been recorded.

    +
    • +
  • +

    Time manipulator: An entity attempting to manipulate timestamps +to alter perceived execution ordering.

    +
    • +
+
+
+
+
+

+10.2. Self-Assertion Limitation +

+

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., setting "pol_decision" to "approved" without actually +evaluating the policy).

+

ECTs do not independently verify that:

+
    +
  • +

    The claimed execution actually occurred as described

    +
    • +
  • +

    The policy evaluation was correctly performed

    +
    • +
  • +

    The input/output hashes correspond to the actual data processed

    +
    • +
  • +

    The agent faithfully performed the stated action

    +
    • +
+

The trustworthiness of ECT claims depends on the trustworthiness +of the signing agent. To mitigate single-agent false claims, +regulated environments SHOULD use the "witnessed_by" mechanism +to include independent third-party observers at critical decision +points.

+
+
+
+
+

+10.3. Organizational Prerequisites +

+

ECTs operate within a broader trust framework. The guarantees +provided by ECTs are only meaningful when the following +organizational controls are in place:

+
    +
  • +

    Key management governance: Controls over who provisions agent +keys and how keys are protected.

    +
    • +
  • +

    Ledger integrity governance: The ledger is maintained by an +entity independent of the workflow agents.

    +
    • +
  • +

    Policy lifecycle management: Policy identifiers in ECTs map to +actual, validated policy rules.

    +
    • +
  • +

    Agent deployment governance: Agents are deployed and maintained +in a manner that preserves their integrity.

    +
    • +
+
+
+
+
+

+10.4. Signature Verification +

+

ECTs MUST be signed with the agent's private key using JWS +[RFC7515]. The signature algorithm MUST match the algorithm +specified in the agent's WIT. Receivers MUST verify the ECT +signature against the WIT public key before processing any +claims. Receivers MUST verify that the signing key has not been +revoked within the trust domain.

+

If signature verification fails, the ECT MUST be rejected entirely +and the failure MUST be logged.

+

Implementations MUST use established JWS libraries and MUST NOT +implement custom signature verification.

+
+
+
+
+

+10.5. Replay Attack Prevention +

+

ECTs include short expiration times (RECOMMENDED: 5-15 minutes) to +limit the window for replay attacks. The "aud" claim restricts +replay to unintended recipients: an ECT intended for Agent B +will be rejected by Agent C. The "iat" claim enables receivers to +reject ECTs that are too old, even if not yet expired.

+

The DAG structure provides additional replay protection: an ECT +referencing parent tasks that already have a recorded child task +with the same action can be flagged as a potential replay.

+

Implementations SHOULD maintain a cache of recently-seen "jti" +values (when present) to detect replayed ECTs within the +expiration window.

+
+
+
+
+

+10.6. Man-in-the-Middle Protection +

+

ECTs do not replace transport-layer security. ECTs MUST be +transmitted over TLS or mTLS connections. When used with the WIMSE +service-to-service protocol [I-D.ietf-wimse-s2s-protocol], +transport security is already established. HTTP Message Signatures +[RFC9421] provide an alternative channel binding mechanism.

+

The defense-in-depth model provides:

+
    +
  • +

    TLS/mTLS (transport layer): Prevents network-level tampering.

    +
    • +
  • +

    WIT/WPT (WIMSE identity layer): Proves agent identity and +request authorization.

    +
    • +
  • +

    ECT (execution accountability layer): Records what the agent did +and under what policy.

    +
    • +
+
+
+
+
+

+10.7. Key Compromise +

+

If an agent's private key is compromised, an attacker can forge +ECTs that appear to originate from that agent. To mitigate this +risk:

+
    +
  • +

    Implementations SHOULD use short-lived keys and rotate them +frequently (hours to days, not months).

    +
    • +
  • +

    Private keys SHOULD be stored in Hardware Security Modules (HSMs) +or equivalent secure key storage.

    +
    • +
  • +

    Trust domains MUST support rapid key revocation.

    +
    • +
  • +

    Upon suspected compromise, the trust domain MUST revoke the +compromised key and issue a new WIT with a fresh key pair.

    +
    • +
+

ECTs signed with a compromised key that were recorded in the +ledger before revocation remain valid historical records but SHOULD +be flagged in the ledger as "signed with subsequently revoked key" +for audit purposes.

+
+
+
+
+

+10.8. Collusion and False Claims +

+

A single malicious agent cannot forge parent task references +because DAG validation requires parent tasks to exist in the +ledger. However, multiple colluding agents could potentially +create a false execution history if they control the ledger.

+

Mitigations include:

+
    +
  • +

    Independent ledger maintenance: The ledger SHOULD be maintained +by an entity independent of the workflow agents.

    +
    • +
  • +

    Witness attestation: Using the "witnessed_by" claim to include +independent third-party observers.

    +
    • +
  • +

    Cross-verification: Multiple independent ledger replicas can be +compared for consistency.

    +
    • +
  • +

    Out-of-band audit: External auditors periodically verify ledger +contents against expected workflow patterns.

    +
    • +
+
+
+
+
+

+10.9. Denial of Service +

+

ECT signature verification is computationally inexpensive +(approximately 1ms per ECT on modern hardware for ES256). DAG +validation complexity is O(V) where V is the number of ancestor +nodes reachable from the parent references; for typical shallow +DAGs this is efficient.

+

Implementations SHOULD apply rate limiting at the API layer to +prevent excessive ECT submissions. DAG validation SHOULD be +performed after signature verification to avoid wasting resources +on unsigned or incorrectly signed tokens.

+
+
+
+
+

+10.10. Timestamp Accuracy +

+

ECTs rely on timestamps ("iat", "exp") for temporal ordering. +Clock skew between agents can lead to incorrect ordering +judgments. Implementations SHOULD use synchronized time sources +(e.g., NTP) and SHOULD allow a configurable clock skew tolerance +(RECOMMENDED: 30 seconds).

+

The temporal ordering check in DAG validation incorporates the +clock skew tolerance to account for minor clock differences +between agents.

+
+
+
+
+

+10.11. ECT Size Constraints +

+

ECTs with many parent tasks or large extension objects can +increase HTTP header size. Implementations SHOULD limit the "par" +array to a reasonable size and SHOULD set maximum size limits for +the "ext" object to prevent abuse.

+
+
+
+
+
+
+

+11. Privacy Considerations +

+
+
+

+11.1. Data Exposure in ECTs +

+

ECTs necessarily reveal:

+
    +
  • +

    Agent identities ("iss", "aud") for accountability purposes

    +
    • +
  • +

    Action descriptions ("exec_act") for audit trail completeness

    +
    • +
  • +

    Policy evaluation outcomes ("pol", "pol_decision") for +compliance verification

    +
    • +
  • +

    Timestamps ("iat", "exp") for temporal ordering

    +
    • +
+

ECTs are designed to NOT reveal:

+
    +
  • +

    Actual input or output data values (replaced with cryptographic +hashes via "inp_hash" and "out_hash")

    +
    • +
  • +

    Internal computation details or intermediate steps

    +
    • +
  • +

    Proprietary algorithms or intellectual property

    +
    • +
  • +

    Personally identifiable information (PII)

    +
    • +
+
+
+
+
+

+11.2. Data Minimization +

+

Implementations SHOULD minimize the information included in ECTs. +The "exec_act" claim SHOULD use structured identifiers (e.g., +"process_payment") rather than natural language descriptions. +The "pol" claim SHOULD reference policy identifiers rather than +embedding policy content.

+
+
+
+
+

+11.3. Storage and Access Control +

+

ECTs stored in audit ledgers SHOULD be access-controlled so that +only authorized auditors and regulators can read them. +Implementations SHOULD consider encryption at rest for ledger +storage containing sensitive regulatory data.

+

Full input and output data (corresponding to the hashes in ECTs) +SHOULD 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.

+
+
+
+
+

+11.4. Regulatory Access +

+

ECTs are designed for interpretation by qualified human auditors +and regulators. ECTs provide structural records of execution +ordering and policy evaluation; they are not intended for public +disclosure.

+
+
+
+
+
+
+

+12. IANA Considerations +

+
+
+

+12.1. Media Type Registration +

+

This document requests registration of the following media type +in the "Media Types" registry maintained by IANA:

+
+
Type name:
+
+

application

+
+
+
Subtype name:
+
+

wimse-exec+jwt

+
+
+
Required parameters:
+
+

none

+
+
+
Optional parameters:
+
+

none

+
+
+
Encoding considerations:
+
+

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.

+
+
+
Security considerations:
+
+

See the Security Considerations section of this document.

+
+
+
Interoperability considerations:
+
+

none

+
+
+
Published specification:
+
+

This document

+
+
+
Applications that use this media type:
+
+

Applications that implement regulated agentic workflows requiring +execution context tracing and audit trails.

+
+
+
Additional information:
+
+

Magic number(s): none +File extension(s): none +Macintosh file type code(s): none

+
+
+
Person and email address to contact for further information:
+
+

Christian Nennemann, ietf@nennemann.de

+
+
+
Intended usage:
+
+

COMMON

+
+
+
Restrictions on usage:
+
+

none

+
+
+
Author:
+
+

Christian Nennemann

+
+
+
Change controller:
+
+

IETF

+
+
+
+
+
+
+
+

+12.2. HTTP Header Field Registration +

+

This document requests registration of the following header field +in the "Hypertext Transfer Protocol (HTTP) Field Name Registry" +maintained by IANA:

+
+
Field name:
+
+

Execution-Context

+
+
+
Status:
+
+

permanent

+
+
+
Specification document:
+
+

This document, Section 5

+
+
+
+
+
+
+
+

+12.3. JWT Claims Registration +

+

This document requests registration of the following claims in +the "JSON Web Token Claims" registry maintained by IANA:

+
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+Table 1: +JWT Claims Registrations +
Claim NameClaim DescriptionChange ControllerReference
widWorkflow IdentifierIETF + Section 4.2.2 +
tidTask IdentifierIETF + Section 4.2.2 +
exec_actAction/Task TypeIETF + Section 4.2.2 +
parParent Task IdentifiersIETF + Section 4.2.2 +
polPolicy Rule IdentifierIETF + Section 4.2.3 +
pol_decisionPolicy Decision ResultIETF + Section 4.2.3 +
pol_enforcerPolicy Enforcer IdentityIETF + Section 4.2.3 +
pol_timestampPolicy Decision TimestampIETF + Section 4.2.3 +
inp_hashInput Data HashIETF + Section 4.2.4 +
out_hashOutput Data HashIETF + Section 4.2.4 +
inp_classificationInput Data ClassificationIETF + Section 4.2.4 +
exec_time_msExecution Time (ms)IETF + Section 4.2.5 +
witnessed_byWitness IdentitiesIETF + Section 4.2.6 +
regulated_domainRegulatory DomainIETF + Section 4.2.5 +
model_versionAI/ML Model VersionIETF + Section 4.2.5 +
compensation_requiredCompensation FlagIETF + Section 4.2.7 +
compensation_reasonCompensation ReasonIETF + Section 4.2.7 +
+
+
+
+
+
+
+
+

+13. References +

+
+
+

+13.1. Normative References +

+
+
[I-D.ietf-wimse-arch]
+
+Salowey, J. A., Rosomakho, Y., and H. Tschofenig, "Workload Identity in a Multi System Environment (WIMSE) Architecture", Work in Progress, Internet-Draft, draft-ietf-wimse-arch-06, , <https://datatracker.ietf.org/doc/html/draft-ietf-wimse-arch-06>.
+
+
[I-D.ietf-wimse-s2s-protocol]
+
+Campbell, B., Salowey, J. A., Schwenkschuster, A., and Y. Sheffer, "WIMSE Workload-to-Workload Authentication", Work in Progress, Internet-Draft, draft-ietf-wimse-s2s-protocol-07, , <https://datatracker.ietf.org/doc/html/draft-ietf-wimse-s2s-protocol-07>.
+
+
[RFC2119]
+
+Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/rfc/rfc2119>.
+
+
[RFC3339]
+
+Klyne, G. and C. Newman, "Date and Time on the Internet: Timestamps", RFC 3339, DOI 10.17487/RFC3339, , <https://www.rfc-editor.org/rfc/rfc3339>.
+
+
[RFC7515]
+
+Jones, M., Bradley, J., and N. Sakimura, "JSON Web Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, , <https://www.rfc-editor.org/rfc/rfc7515>.
+
+
[RFC7518]
+
+Jones, M., "JSON Web Algorithms (JWA)", RFC 7518, DOI 10.17487/RFC7518, , <https://www.rfc-editor.org/rfc/rfc7518>.
+
+
[RFC7519]
+
+Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token (JWT)", RFC 7519, DOI 10.17487/RFC7519, , <https://www.rfc-editor.org/rfc/rfc7519>.
+
+
[RFC8174]
+
+Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/rfc/rfc8174>.
+
+
[RFC9110]
+
+Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, Ed., "HTTP Semantics", STD 97, RFC 9110, DOI 10.17487/RFC9110, , <https://www.rfc-editor.org/rfc/rfc9110>.
+
+
[RFC9562]
+
+Davis, K., Peabody, B., and P. Leach, "Universally Unique IDentifiers (UUIDs)", RFC 9562, DOI 10.17487/RFC9562, , <https://www.rfc-editor.org/rfc/rfc9562>.
+
+
+
+
+
+
+

+13.2. Informative References +

+
+
[DORA]
+
+European Parliament and Council of the European Union, "Regulation (EU) 2022/2554 on digital operational resilience for the financial sector (DORA)", , <https://eur-lex.europa.eu/eli/reg/2022/2554>.
+
+
[EU-AI-ACT]
+
+European Parliament and Council of the European Union, "Regulation (EU) 2024/1689 of the European Parliament and of the Council laying down harmonised rules on artificial intelligence (Artificial Intelligence Act)", , <https://eur-lex.europa.eu/eli/reg/2024/1689>.
+
+
[EU-MDR]
+
+European Parliament and Council of the European Union, "Regulation (EU) 2017/745 on medical devices (MDR)", , <https://eur-lex.europa.eu/eli/reg/2017/745>.
+
+
[FDA-21CFR11]
+
+U.S. Food and Drug Administration, "Title 21, Code of Federal Regulations, Part 11: Electronic Records; Electronic Signatures", <https://www.ecfr.gov/current/title-21/chapter-I/subchapter-A/part-11>.
+
+
[I-D.ni-wimse-ai-agent-identity]
+
+Yuan, N. and P. C. Liu, "WIMSE Applicability for AI Agents", Work in Progress, Internet-Draft, draft-ni-wimse-ai-agent-identity-01, , <https://datatracker.ietf.org/doc/html/draft-ni-wimse-ai-agent-identity-01>.
+
+
[MIFID-II]
+
+European Parliament and Council of the European Union, "Directive 2014/65/EU of the European Parliament and of the Council on markets in financial instruments (MiFID II)", , <https://eur-lex.europa.eu/eli/dir/2014/65>.
+
+
[OPENTELEMETRY]
+
+Cloud Native Computing Foundation, "OpenTelemetry Specification", <https://opentelemetry.io/docs/specs/otel/>.
+
+
[RFC3552]
+
+Rescorla, E. and B. Korver, "Guidelines for Writing RFC Text on Security Considerations", BCP 72, RFC 3552, DOI 10.17487/RFC3552, , <https://www.rfc-editor.org/rfc/rfc3552>.
+
+
[RFC7517]
+
+Jones, M., "JSON Web Key (JWK)", RFC 7517, DOI 10.17487/RFC7517, , <https://www.rfc-editor.org/rfc/rfc7517>.
+
+
[RFC8693]
+
+Jones, M., Nadalin, A., Campbell, B., Ed., Bradley, J., and C. Mortimore, "OAuth 2.0 Token Exchange", RFC 8693, DOI 10.17487/RFC8693, , <https://www.rfc-editor.org/rfc/rfc8693>.
+
+
[RFC9421]
+
+Backman, A., Ed., Richer, J., Ed., and M. Sporny, "HTTP Message Signatures", RFC 9421, DOI 10.17487/RFC9421, , <https://www.rfc-editor.org/rfc/rfc9421>.
+
+
[SPIFFE]
+
+"Secure Production Identity Framework for Everyone (SPIFFE)", <https://spiffe.io/docs/latest/spiffe-about/overview/>.
+
+
+
+
+
+
+ +
+
+

+Implementation Guidance +

+
+
+

+Minimal Implementation +

+

A minimal conforming implementation should:

+
    +
  1. +

    Create JWTs with all required claims ("iss", "aud", "iat", +"exp", "tid", "exec_act", "par", "pol", "pol_decision").

    +
    2. +
  2. +

    Sign ECTs with the agent's private key using an algorithm +matching the WIT (ES256 recommended).

    +
    3. +
  3. +

    Verify ECT signatures against WIT public keys.

    +
    4. +
  4. +

    Perform DAG validation (parent existence, temporal ordering, +cycle detection).

    +
    5. +
  5. +

    Append verified ECTs to an audit ledger.

    +
    6. +
+
+
+
+
+

+Storage Recommendations +

+
    +
  • +

    Append-only log: Simplest approach; immutability by design.

    +
    • +
  • +

    Database with hash chains: Periodic cryptographic commitments +over batches of entries.

    +
    • +
  • +

    Distributed ledger: Maximum immutability guarantees for +cross-organizational audit.

    +
    • +
  • +

    Hybrid: Hot storage in a database, cold archive in immutable +storage.

    +
    • +
+
+
+
+
+

+Performance Considerations +

+
    +
  • +

    ES256 signature verification: approximately 1ms per ECT on +modern hardware.

    +
    • +
  • +

    DAG validation: O(V) where V is the number of reachable ancestor +nodes (typically small for shallow workflows).

    +
    • +
  • +

    JSON serialization: sub-millisecond per ECT.

    +
    • +
  • +

    Total per-request overhead: approximately 5-10ms, acceptable +for regulated workflows where correctness is prioritized over +latency.

    +
    • +
+
+
+
+
+

+Interoperability +

+

Implementations should use established JWT/JWS libraries (JOSE) +for token creation and verification. Custom cryptographic +implementations should not be used. Implementations should be +tested against multiple JWT libraries to ensure interoperability.

+
+
+
+
+
+
+

+Regulatory Compliance Mapping +

+

The following table summarizes how ECTs can contribute to +compliance with various regulatory frameworks. ECTs are a +technical building block; achieving compliance requires +additional organizational measures beyond this specification.

+
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+Table 2: +Regulatory Compliance Mapping +
RegulationRequirementECT Contribution
FDA 21 CFR Part 11Audit trails recording date, time, operator, actions (11.10(e))Cryptographic signatures and append-only ledger contribute to audit trail requirements
EU MDRTechnical documentation traceability (Annex II)ECTs provide signed records of AI-assisted decision sequences
EU AI Act Art. 12Automatic logging capabilities for high-risk AIECTs contribute cryptographic activity logging
EU AI Act Art. 14Human oversight capabilityECTs can record evidence that human oversight events occurred
MiFID IITransaction records for supervisory authoritiesECTs provide cryptographic execution sequence records
DORA Art. 12ICT activity logging policiesECT ledger contributes to ICT activity audit trail
+
+
+
+
+
+

+Examples +

+
+
+

+Example 1: Simple Two-Agent Workflow +

+

Agent A executes a data retrieval task and sends the ECT to +Agent B:

+

ECT JOSE Header:

+
+
+{
+  "alg": "ES256",
+  "typ": "wimse-exec+jwt",
+  "kid": "agent-a-key-2026-02"
+}
+
+
+

ECT Payload:

+
+
+{
+  "iss": "spiffe://example.com/agent/data-retrieval",
+  "sub": "spiffe://example.com/agent/data-retrieval",
+  "aud": "spiffe://example.com/agent/validator",
+  "iat": 1772064150,
+  "exp": 1772064750,
+  "wid": "b1c2d3e4-f5a6-7890-bcde-f01234567890",
+  "tid": "550e8400-e29b-41d4-a716-446655440001",
+  "exec_act": "fetch_patient_data",
+  "par": [],
+  "pol": "clinical_data_access_policy_v1",
+  "pol_decision": "approved",
+  "inp_hash": "sha-256:n4bQgYhMfWWaL-qgxVrQFaO_TxsrC4Is0V1sFbDwCgg",
+  "out_hash": "sha-256:LCa0a2j_xo_5m0U8HTBBNBNCLXBkg7-g-YpeiGJm564",
+  "exec_time_ms": 142,
+  "regulated_domain": "medtech"
+}
+
+
+

Agent B receives the ECT, verifies it, executes a validation +task, and creates its own ECT:

+
+
+{
+  "iss": "spiffe://example.com/agent/validator",
+  "sub": "spiffe://example.com/agent/validator",
+  "aud": "spiffe://example.com/system/ledger",
+  "iat": 1772064160,
+  "exp": 1772064760,
+  "wid": "b1c2d3e4-f5a6-7890-bcde-f01234567890",
+  "tid": "550e8400-e29b-41d4-a716-446655440002",
+  "exec_act": "validate_safety",
+  "par": ["550e8400-e29b-41d4-a716-446655440001"],
+  "pol": "safety_validation_policy_v2",
+  "pol_decision": "approved",
+  "exec_time_ms": 89,
+  "regulated_domain": "medtech"
+}
+
+
+

The resulting DAG:

+
+
+task-...-0001 (fetch_patient_data)
+  |
+  v
+task-...-0002 (validate_safety)
+
+
+
+
+
+
+

+Example 2: Medical Device SDLC with Release Approval +

+

A multi-step medical device software lifecycle workflow with +autonomous agents and human release approval:

+

Task 1 (Spec Review Agent):

+
+
+{
+  "iss": "spiffe://meddev.example/agent/spec-reviewer",
+  "sub": "spiffe://meddev.example/agent/spec-reviewer",
+  "aud": "spiffe://meddev.example/agent/code-gen",
+  "iat": 1772064150,
+  "exp": 1772064750,
+  "wid": "c2d3e4f5-a6b7-8901-cdef-012345678901",
+  "tid": "a1b2c3d4-0001-0000-0000-000000000001",
+  "exec_act": "review_requirements_spec",
+  "par": [],
+  "pol": "spec_review_policy_v2",
+  "pol_decision": "approved",
+  "regulated_domain": "medtech",
+  "model_version": "spec-review-v3.1",
+  "inp_hash": "sha-256:n4bQgYhMfWWaL-qgxVrQFaO_TxsrC4Is0V1sFbDwCgg",
+  "out_hash": "sha-256:LCa0a2j_xo_5m0U8HTBBNBNCLXBkg7-g-YpeiGJm564"
+}
+
+
+

Task 2 (Code Generation Agent):

+
+
+{
+  "iss": "spiffe://meddev.example/agent/code-gen",
+  "sub": "spiffe://meddev.example/agent/code-gen",
+  "aud": "spiffe://meddev.example/agent/test-runner",
+  "iat": 1772064200,
+  "exp": 1772064800,
+  "wid": "c2d3e4f5-a6b7-8901-cdef-012345678901",
+  "tid": "a1b2c3d4-0001-0000-0000-000000000002",
+  "exec_act": "implement_module",
+  "par": ["a1b2c3d4-0001-0000-0000-000000000001"],
+  "pol": "coding_standards_v3",
+  "pol_decision": "approved",
+  "regulated_domain": "medtech",
+  "model_version": "codegen-v2.4"
+}
+
+
+

Task 3 (Autonomous Test Agent):

+
+
+{
+  "iss": "spiffe://meddev.example/agent/test-runner",
+  "sub": "spiffe://meddev.example/agent/test-runner",
+  "aud": "spiffe://meddev.example/agent/build",
+  "iat": 1772064260,
+  "exp": 1772064860,
+  "wid": "c2d3e4f5-a6b7-8901-cdef-012345678901",
+  "tid": "a1b2c3d4-0001-0000-0000-000000000003",
+  "exec_act": "execute_test_suite",
+  "par": ["a1b2c3d4-0001-0000-0000-000000000002"],
+  "pol": "test_coverage_policy_v1",
+  "pol_decision": "approved",
+  "regulated_domain": "medtech",
+  "exec_time_ms": 4523
+}
+
+
+

Task 4 (Build Agent):

+
+
+{
+  "iss": "spiffe://meddev.example/agent/build",
+  "sub": "spiffe://meddev.example/agent/build",
+  "aud": "spiffe://meddev.example/human/release-mgr-42",
+  "iat": 1772064310,
+  "exp": 1772064910,
+  "wid": "c2d3e4f5-a6b7-8901-cdef-012345678901",
+  "tid": "a1b2c3d4-0001-0000-0000-000000000004",
+  "exec_act": "build_release_artifact",
+  "par": ["a1b2c3d4-0001-0000-0000-000000000003"],
+  "pol": "build_validation_v2",
+  "pol_decision": "approved",
+  "regulated_domain": "medtech",
+  "out_hash": "sha-256:Ry1YfOoW2XpC5Mq8HkGzNx3dL9vBa4sUjE7iKt0wPZc"
+}
+
+
+

Task 5 (Human Release Manager Approval):

+
+
+{
+  "iss": "spiffe://meddev.example/human/release-mgr-42",
+  "sub": "spiffe://meddev.example/human/release-mgr-42",
+  "aud": "spiffe://meddev.example/system/ledger",
+  "iat": 1772064510,
+  "exp": 1772065110,
+  "wid": "c2d3e4f5-a6b7-8901-cdef-012345678901",
+  "tid": "a1b2c3d4-0001-0000-0000-000000000005",
+  "exec_act": "approve_release",
+  "par": ["a1b2c3d4-0001-0000-0000-000000000004"],
+  "pol": "release_approval_policy",
+  "pol_decision": "approved",
+  "pol_enforcer": "spiffe://meddev.example/human/release-mgr-42",
+  "witnessed_by": [
+    "spiffe://meddev.example/audit/qa-observer-1"
+  ],
+  "regulated_domain": "medtech"
+}
+
+
+

The resulting DAG records the complete SDLC: spec review preceded +implementation, implementation preceded testing, testing preceded +build, and a human release manager approved the final release +with independent witness attestation.

+
+
+task-...-0001 (review_requirements_spec)
+  |
+  v
+task-...-0002 (implement_module)
+  |
+  v
+task-...-0003 (execute_test_suite)
+  |
+  v
+task-...-0004 (build_release_artifact)
+  |
+  v
+task-...-0005 (approve_release) [human, witnessed]
+
+
+

An FDA auditor reconstructs this DAG by querying the audit ledger +for all ECTs with wid "c2d3e4f5-a6b7-8901-cdef-012345678901" and +verifying each signature. The DAG provides cryptographic evidence +that the SDLC followed the prescribed process with human oversight +at the release gate.

+
+
+
+
+

+Example 3: Parallel Execution with Join +

+

A workflow where two tasks execute in parallel and a third task +depends on both:

+
+
+task-...-0001 (assess_risk)
+  |            \
+  v             v
+task-...-0002  task-...-0003
+(check         (verify
+compliance)    liquidity)
+  |            /
+  v           v
+task-...-0004 (execute_trade)
+
+
+

Task 004 ECT payload:

+
+
+{
+  "iss": "spiffe://bank.example/agent/execution",
+  "sub": "spiffe://bank.example/agent/execution",
+  "aud": "spiffe://bank.example/system/ledger",
+  "iat": 1772064250,
+  "exp": 1772064850,
+  "wid": "d3e4f5a6-b7c8-9012-def0-123456789012",
+  "tid": "f1e2d3c4-0004-0000-0000-000000000004",
+  "exec_act": "execute_trade",
+  "par": [
+    "f1e2d3c4-0002-0000-0000-000000000002",
+    "f1e2d3c4-0003-0000-0000-000000000003"
+  ],
+  "pol": "trade_execution_policy_v3",
+  "pol_decision": "approved",
+  "regulated_domain": "finance"
+}
+
+
+

The "par" array with two entries records that both compliance +checking and liquidity verification were completed before trade +execution.

+
+
+
+
+
+
+

+Acknowledgments +

+

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.

+
+
+
+
+

+Author's Address +

+
+
Christian Nennemann
+
Independent Researcher
+ +
+
+
+ + +