Network Working Group K. McGuinness Internet-Draft Independent Intended status: Standards Track 23 June 2026 Expires: 25 December 2026 Mission-Bound Runtime Enforcement for OAuth 2.0 draft-mcguinness-oauth-mission-runtime-latest Abstract The Mission-Bound Authorization for OAuth 2.0 profile binds issued authority to a durable, approved Mission, but it governs issuance and derivation only: it does not evaluate individual runtime actions, so an active Mission can become ambient authority for the actions an agent takes within a token's lifetime. This document specifies the companion runtime layer for deployments that claim runtime Mission enforcement. Within a declared enforcement scope, each consequential action is evaluated, before it executes, against the Mission the acting credential is bound to. The evaluation checks the action and its parameters against the Mission's approved authority and constraints, the actor context from the delegation chain, and the Mission against its current state. The document defines where enforcement MUST sit, how a permit is bound to concrete parameters to close the time-of-check to time-of-use gap, how carried consumption bounds (budget, call counts, duration) are metered, and the runtime evidence each consequential action MUST produce. About This Document This note is to be removed before publishing as an RFC. The latest revision of this draft can be found at https://mcguinness.github.io/draft-mcguinness-oauth-mission/draft- mcguinness-oauth-mission-runtime.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft- mcguinness-oauth-mission-runtime/. Source for this draft and an issue tracker can be found at https://github.com/mcguinness/draft-mcguinness-oauth-mission. 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 25 December 2026. Copyright Notice Copyright (c) 2026 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) 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. Table of Contents 1. Introduction 1.1. Relationship to the issuance profile 1.2. Conventions and Terminology 2. Runtime model 2.1. Enforcement flow 2.2. Enforcement scope and conformance 2.3. Action classification 2.4. PEP placement 3. Resource Server runtime profile 4. Token presentation and validation 5. The decision 5.1. Mission state and freshness 6. Parameter binding and time-of-check to time-of-use 7. Consumption metering 8. Failure modes 9. Runtime enforcement evidence 9.1. Required decision evidence 9.2. Execution-outcome evidence 9.3. Record integrity and retention 10. Example decision API binding: AuthZEN 11. Out of scope 12. Security Considerations 12.1. What this layer adds, and its limits 12.2. Placement and bypass 12.3. Classification integrity 12.4. Freshness and consumption honesty 12.5. Resource policy remains authoritative 12.6. TOCTOU and replay 12.7. Confused deputy across resources 12.8. Decision channel and token disclosure 12.9. Evidence privacy and correlation 13. IANA Considerations 14. References 14.1. Normative References 14.2. Informative References Acknowledgments Author's Address 1. Introduction Mission-Bound Authorization for OAuth 2.0 [I-D.draft-mcguinness-oauth-mission] (the "issuance profile") makes a Mission a first-class OAuth artifact: a structured, human-approved, integrity-bound task whose authority bounds and outlives every token an agent derives. But it is deliberately an issuance-and-derivation layer. As its security considerations state, it does not evaluate individual runtime actions, so an active Mission still bounds a set of authority an agent may exercise freely within a token's lifetime, and preventing that authority from becoming ambient for individual consequential actions requires a separate runtime enforcement layer. This document is that layer. It delivers exactly the four things the issuance profile names as out of scope, plus enforcement of the constraints that profile carries but does not evaluate: 1. evaluation of a request's parameters against the Mission at the point of use (Section 5, Section 6); 2. per-action runtime enforcement evidence (Section 9); 3. binding of the invoked tool or function identity to the Mission's approved authority (Section 5); 4. execution-time re-evaluation that closes the approval-to- execution (time-of-check to time-of-use) gap (Section 6); and, additionally, metering of the consumption bounds (budget, call counts, duration) the issuance profile carries as constraints but leaves to this layer to enforce (Section 7). The model is a Policy Enforcement Point (PEP) at each consequential execution boundary that, before the action runs, obtains a decision from a Policy Decision Point (PDP) evaluating the action against the Mission. Mission-bound tokens bound what authority may exist; this profile defines where and how that authority is re-checked before consequential effects occur. This profile specifies enforcement invariants, not a wire protocol: it does not standardize a PDP decision API, an enforcement-scope discovery format, a Mission Status endpoint, or a portable audit receipt. It defines what a deployment MUST satisfy when it claims runtime Mission enforcement; the surfaces it deliberately leaves to deployments or future work are collected in Section 11. 1.1. Relationship to the issuance profile This document depends normatively on the issuance profile and is not implementable alone: it consumes Mission-bound access tokens that profile defines. It does not place any new requirement back on the issuance profile; it reads only fields that profile already defines: * the mission claim (id, origin, authority_hash); * the token's authorization_details, including entries of type mission_resource_access (resource, actions, constraints, and any delegation member) and any other entry type the deployment supports under the issuance profile's rules; * the act chain, when delegation is in effect; * the standard iss, aud, sub, client_id, and exp claims, when present in the token format; and * any cnf sender-constraint binding. Where this document needs a value the token does not carry (the current Mission lifecycle state, or a materialized policy-view version), it obtains it at runtime as described below, never by requiring the issuance profile to add a field. The Resource Server enforcement rules in the issuance profile remain the baseline for every Mission-bound access token. This document adds an optional runtime conformance profile for deployments that claim execution-time Mission enforcement; it does not weaken the issuance profile's stateless token-validation, subset, delegation, or constraint-enforcement requirements. 1.2. Conventions and Terminology 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. This specification uses the terms "access token", "Authorization Server", "client", "protected resource", "resource owner", and "Resource Server" from OAuth 2.0 [RFC6749] through the terminology incorporated by [I-D.draft-mcguinness-oauth-mission]. It also uses the Mission, Mission Intent, Mission Issuer, Authority Set, Approver, delegation, and mission claim terminology from [I-D.draft-mcguinness-oauth-mission]. Policy Enforcement Point (PEP): The component that can prevent a consequential action and that obtains and enforces a decision before the action runs. Depending on the action this is a Resource Server, an MCP server, an egress proxy, a workflow engine, or the orchestrator itself. Policy Decision Point (PDP): The component that evaluates a consequential action against the Mission and returns permit or deny. Its placement is a deployment choice (Section 5). Resource policy: Local policy of the Resource Server or protected resource, including object-level authorization, tenant configuration, legal holds, service invariants, and risk decisions. Mission authority is an upper bound and does not override Resource policy. Consequential action: An action that has external visibility or effect and so MUST be evaluated before it runs (Section 2.3). Decision: A PDP's permit-or-deny result for one action, bound to the inputs it evaluated (Section 5). Policy-view version: A deployment-opaque identifier the PDP emits for the materialized policy and Mission view it evaluated against, so a permit and its evidence record tie to a reproducible decision basis. It need not reveal policy content; it is a correlator that lets an operator determine which materialized policy, Mission state view, and constraint interpretation a decision used. It is local to the runtime layer and is distinct from the issuance profile's policy_version Mission-record field ([I-D.draft-mcguinness-oauth-mission]); this document does not interpret it beyond correlation, and defines no portable policy- version registry. Runtime enforcement evidence: The record a consequential action produces for a PDP decision or a PEP refusal path (Section 9). Enforcement scope: The set of resources, action classes, execution paths, PEP placements, supported authorization details, state sources, and evidence mechanisms for which a deployment claims conformance to this profile. Operation profile: Deployment documentation that defines operation- specific runtime semantics needed for interoperable enforcement within that deployment, including parameter normalization rules and duration measurement. Resource Server runtime profile: A deployment's Resource Server- facing conformance statement for this profile. It defines which protected resources and operations the Resource Server enforces, where the PEP sits, how local Resource policy composes with Mission authority, and which operation profiles apply. Mission state source: A deployment-trusted source from which the PDP establishes the Mission lifecycle state or the freshness of that state (Section 5.1). Mission-bound token: An access token issued under a Mission per [I-D.draft-mcguinness-oauth-mission], carrying authorization_details and a mission claim. 2. Runtime model 2.1. Enforcement flow Agent PEP (action boundary) PDP | | | |- action+params ->| | | | validate token | | |- evaluate vs Mission ->| | | (authority, params, | | | actor, state) | | |<---- permit / deny ----| | | bind to params; | | | write evidence | |<- execute/refuse-| | The PEP first validates the token as described in Section 4. On permit the PEP reverifies the parameter binding, then executes; on deny it refuses. The runtime decision evaluates the action against the Mission's authority, the entry constraints, the actor chain, the Mission's current state, and Resource policy, as defined in Section 5. 2.2. Enforcement scope and conformance This profile is implemented by a runtime deployment, not by an OAuth Authorization Server alone. Three things conform, at different granularities: the *runtime deployment* (this section), the *Resource Server runtime profile* for OAuth-protected resources (Section 3), and the *PEP/PDP decision path* for each consequential action (Section 5). Conformance is not global to a product, Authorization Server, Resource Server, or PDP: a deployment conforms to this profile only for the resources, action classes, execution paths, and authorization-detail types named in its enforcement scope. A deployment that claims conformance to this profile MUST document its enforcement scope, including: * the protected resources, action classes, and execution paths it mediates; * the PEP locations that can prevent those actions; * the PDP or PDPs that evaluate Mission-bound decisions; * the authorization_details types, action identifiers, and constraint vocabularies it supports; * any Resource Server runtime profile and operation profiles it uses (Section 3); * the Mission state source and maximum staleness bound used for each action class (Section 5.1); * the runtime enforcement evidence mechanism and retention window (Section 9); and * any consumption-metering consistency bound it advertises (Section 7). A deployment MUST NOT claim runtime enforcement for a resource, action class, authorization_details type, or execution path outside that declared scope. A Mission Issuer conforms to the issuance profile; it does not become a runtime-conforming deployment merely by issuing Mission-bound tokens. The enforcement scope is a deployment conformance statement, not an OAuth Authorization Server metadata extension. This document defines no discovery mechanism, registry, or wire format for publishing it. Different deployments can document scope through configuration, operational policy, resource-server metadata defined elsewhere, or a contractual profile. 2.3. Action classification The boundary between consequential and non-consequential actions is deployment policy, but a deployment MUST NOT define it so loosely that nothing is enforced. This document defines a default classification a deployment SHOULD adopt, and a floor it MUST observe. +===================+==================+==========+================+ | Class | Examples | PDP gate | Parameter | | | | | binding | +===================+==================+==========+================+ | Non-consequential | internal | not | n/a | | | reasoning, cache | required | | | | reads, planning | | | +-------------------+------------------+----------+----------------+ | Consequential | reading user | MUST | not required | | read | data, querying | | | | | logged APIs | | | +-------------------+------------------+----------+----------------+ | Consequential | updating | MUST | MUST | | write | records, posting | | | | | messages | | | +-------------------+------------------+----------+----------------+ | Irreversible | sending mail, | MUST | MUST, with | | action | payment, | | TOCTOU | | | deletion | | reverification | +-------------------+------------------+----------+----------------+ | External | signing, | MUST | MUST, with | | commitment | accepting terms | | TOCTOU | | | for the user | | reverification | | | | | and evidence | +-------------------+------------------+----------+----------------+ | Privileged | granting access, | MUST | MUST, with | | administration | changing policy | | TOCTOU and | | | | | evidence | +-------------------+------------------+----------+----------------+ Table 1 The table's per-class requirements (the PDP gate and parameter binding) are requirements for an action *once it is assigned to that class*. Assigning an action to a class is deployment policy, bounded by the floor below and by any Resource-policy minimum (Section 5): the profile does not require every read to reach a PDP. A read that is already fully constrained by the token's audience, resource, and the Resource Server's object-level authorization, and that does not materially affect the resource set or disclosure risk, need not be classified a consequential read, and is then not separately PDP-gated by this profile. A deployment MUST NOT, however, use classification to evade the floor or a Resource-policy minimum, and once an action is a consequential write or higher it MUST be gated and bound as the table requires. *Classification floor.* Actions in the *irreversible*, *external commitment*, and *privileged administration* classes MUST be treated as consequential and gated. A Mission's purpose, or deployment policy, MAY raise an action to a stricter class; it MUST NOT lower an action below any minimum classification the Resource policy (Section 5) sets for it, and in any case MUST NOT classify an irreversible, external-commitment, or privileged-administration action as non-consequential. A deployment that leaves such an action ungated does not enforce this profile for that action's class (Section 2.4). A deployment policy can require human confirmation, step-up authentication, or another local signal for privileged administration or external commitments. This profile does not define such a signal. Consequential reads do not require parameter binding by default. However, a deployment MUST bind or digest read parameters when those parameters materially change the effective resource set or disclosure risk. Examples include export-like reads, bulk reads, cross-tenant or cross-account queries, privacy-sensitive filters, field selection that controls sensitive attributes, destination or delivery parameters, and aggregation choices that affect re-identification risk. 2.4. PEP placement Enforcement only works at the component that can actually stop the action. A deployment claiming this profile MUST observe these rules: * The PEP MUST sit at the last controllable boundary before the action. A permit checked further upstream does not survive parameter changes, retries, or routing that happen after the check. * A token-issuance decision does not replace execution-time authorization. A token-only Resource Server cannot claim runtime enforcement; the issuance gate is governance, the runtime gate is enforcement. * A tool-catalog filter does not replace per-call authorization. Filtering a tool list by the caller's authority is exposure control; every consequential tool call MUST still pass the runtime gate. * An orchestrator's internal check does not replace a Resource Server's PEP. Defense in depth is permitted; substitution is not. * If no PEP can prevent the action for a given class, the deployment MUST NOT claim runtime enforcement for that class, and MUST name the action classes and execution paths it does mediate. The boundary varies by action: an OAuth-protected API call is gated at the Resource Server; a consequential MCP tools/call at the MCP server; a local tool invocation, file write, or payment at the orchestrator or whatever component drives the call; external egress at an egress proxy. Where an action can be reached by an unmediated path (a debug shell, an unsanctioned egress route, a direct connector), the profile is not enforced for the classes that path reaches. 3. Resource Server runtime profile An OAuth Resource Server that claims conformance to this runtime profile MUST publish or otherwise make available a Resource Server runtime profile for the protected resources and operations in scope. The Resource Server runtime profile is a deployment conformance statement, not an OAuth Authorization Server metadata extension and not a new access token format. The Resource Server runtime profile MUST define: * the protected resources, endpoint families, methods, tools, or operation identifiers for which Mission runtime enforcement applies; * the minimum action class for each protected operation, including any Resource policy floor that raises the class above the default classification in Section 2.3; * the PEP location that can prevent each protected operation and any known execution path that is outside the claim; * the PDP or PDPs used for Mission-bound runtime decisions, including how the PEP and PDP authenticate and integrity-protect decision requests and responses when they are separate components; * the supported authorization_details types, action identifiers, and constraint vocabularies for those operations; * the operation profile for each protected operation or operation family, including parameter normalization, default insertion, omitted optional fields, set-like array handling, idempotency-key handling, and duration measurement when duration can be metered; * the Mission state source, maximum staleness bound, and permit validity window used for each action class; * how Resource policy is evaluated and composed with Mission authority, including local object authorization, tenant configuration, legal holds, service invariants, and risk policy; * replay controls for permit use, including where single-use decision identifiers and idempotency keys are recorded and how long consumed identifiers are retained; * any consumption-metering topology and consistency bound, including reserve, commit, settlement, retry, and reconciliation behavior; and * the runtime enforcement evidence fields, retention window, and privacy treatment for decision and refusal records. A Resource Server MUST NOT claim this runtime profile for an operation unless the operation's consequential effects pass through a PEP that can refuse the operation after token validation and before execution. A Resource Server that only validates the access token and checks static token audience or scope claims does not implement this runtime profile. The Resource Server runtime profile MAY be documented in Resource Server configuration, resource-server metadata defined elsewhere, a contractual deployment profile, or another deployment-specific mechanism. This document does not define a discovery document, registry, or wire format for publishing it. 4. Token presentation and validation The runtime decision is downstream of ordinary access token validation. Before using a token's Mission, authority, subject, client, actor, or confirmation-key values as decision inputs, the PEP MUST establish that the access token is valid for the protected resource and request. For the Mission-bound JWT access tokens defined by the issuance profile, this means validating the JWT per [RFC9068], verifying the issuer and audience, checking token expiry, and verifying any sender-constraint binding (cnf) under the proof-of- possession rules of the issuance profile ([I-D.draft-mcguinness-oauth-mission]); this profile defines no proof-of-possession mechanism of its own. The underlying OAuth deployment MUST follow the applicable security best current practice in [RFC9700]. In particular, a Resource Server PEP MUST refuse a token whose audience is not intended for that Resource Server, and MUST verify the proof-of-possession check for a sender-constrained token before treating its cnf binding as authenticated. A PEP MUST NOT ask a PDP to authorize an action from unverified token claims. If token validation fails, or if the deployment requires Mission governance for the protected operation and the token lacks a mission claim, the PEP MUST refuse before runtime Mission evaluation. When the PEP is an OAuth Resource Server, it uses the normal OAuth error behavior for the protected resource (for example, Bearer token errors under [RFC6750]); this profile defines no new OAuth error code. Where the PEP and PDP are separate components, the decision request and response MUST be integrity-protected and the parties MUST authenticate each other. The PDP MUST accept token-derived inputs only from a PEP authorized for the declared enforcement scope. A deployment can satisfy this with a mutually authenticated channel, a signed decision request and response, or another mechanism with equivalent security properties. The PEP SHOULD send the PDP the minimum token-derived claims needed for the decision rather than the presented access token. If a deployment sends the access token itself to the PDP, the PDP MUST treat it as a credential, protect it against disclosure, and MUST NOT use it outside the declared enforcement scope. 5. The decision Before a consequential action runs, its PEP MUST obtain a permit from a PDP that evaluates the action against the Mission the acting token is bound to. This is the normative contract. The decision API wire format is a deployment choice; Section 10 gives a non-normative example binding. The PEP MUST supply the inputs the PDP needs for the Mission-bound decision. Runtime enforcement MUST evaluate: * *Authority.* The action MUST be authorized by an applicable authorization_details entry the Mission-bound token carries, or that is otherwise available to the PEP or PDP for that token under the issuance profile (for example, through introspection when the authority is not represented inline). For an entry of type mission_resource_access, the action's resource and invoked action or tool identity MUST be within that entry's resource and actions, under the subset rule of [I-D.draft-mcguinness-oauth-mission]. The PEP asserts the capability identity (for example, the tool or function name) it will invoke; the PDP MUST refuse an identity outside the approved actions. For any other authorization_details type, the PDP MUST evaluate the action under that type's documented runtime semantics and MUST refuse if it does not understand or cannot enforce those semantics. Richer capability- source binding (source digests, cross-format identity) is out of scope (Section 11). * *Resource policy.* The runtime decision MUST include any applicable Resource policy. A Mission-bound token and runtime permit are an upper bound on authority, not a command for the Resource Server to perform the action. Resource policy MAY be evaluated by the PDP, by the Resource Server or PEP as a composed local authorization step, or by both. The action MUST fail closed unless both Mission authority and Resource policy permit it. Resource policy includes object-level authorization, tenant configuration, legal holds, service invariants, and risk policy. * *Parameters.* Every constraints value on the applicable entry MUST be evaluated against the concrete action parameters. A constraint the PDP does not understand or cannot enforce or meter MUST cause refusal; it MUST NOT be ignored or reduced to disclosure-only treatment. * *Actor.* When delegation is in effect, the PDP MUST evaluate the authenticated act chain as part of the runtime actor context and refuse a chain that is missing or malformed. Runtime enforcement consumes the actor context that results from the issuance profile's delegation checks; it does not recompute the issuance- time subset validation, and the runtime decision MUST NOT expand authority beyond the issued authorization_details. The issuance profile's delegation constraints are not re-applied here unless the deployment documents them as runtime Resource policy, but a deployment MAY apply additional actor-sensitive Resource policy (Section 5). When an act chain is present, the PDP MUST NOT treat client_id alone as the immediate actor. * *Time.* The PDP MUST refuse if the decision context indicates the token is expired. The issuance profile caps a derived token's exp at mission_expiry, so the exp check enforces the Mission's expiry transitively. The standard mission claim and introspection do not surface mission_expiry; where a Mission state source does expose it (or reports the Mission expired), the PDP MUST refuse on it independent of the token's own exp. The PDP sets the permit's validity window from these inputs; that the action actually executes within that window is the executing PEP's reverification, not a decision input (Section 6). * *State.* The PDP MUST refuse unless the Mission is active (Section 5.1). On a deny, the PEP MUST refuse the action. Authority-expandable denials and the escalation workflow that turns a deny into a Mission expansion are out of scope and deferred (Section 11); in this profile a deny is terminal for the attempted action. The PDP's placement is a deployment choice (co-located with the Mission's origin, embedded in the Resource Server, a tenant-scoped service, or a shared service); this document does not mandate one. The requirement is only that a PEP at each consequential boundary can reach an applicable PDP. 5.1. Mission state and freshness A Mission-aware decision needs the Mission's current state, which a token alone does not convey. A runtime deployment MUST define the Mission state source it trusts for each enforcement scope. Examples include origin AS token introspection, a local Mission database, an authenticated status or event feed from the Mission origin, a materialized policy view, or a short-lived cross-domain credential whose lifetime is the deployment's accepted state lease. * The PDP MUST refuse a consequential action when it cannot establish, within the deployment's published staleness bound, that the Mission is active. * A state source MUST either report the Mission state with a freshness time, or define a lease interval over which a previously established active state remains acceptable for the relevant action class. A permit issued from that state view MUST expire no later than the applicable freshness time or lease interval. * When the credential issuer also holds the Mission, the PDP can learn state through token introspection ([RFC7662]) at the issuer per [I-D.draft-mcguinness-oauth-mission]. A non-origin Resource AS introspecting a local token cannot report current Mission state under the issuance profile; it can establish local token validity, but not origin Mission freshness. * This document defines no cross-issuer by-Mission status query. Deployments that need tighter freshness than the token or cross- domain grant lifetime provides need an out-of-band trusted status feed or a future standardized Mission Status surface. * Each enforcement scope MUST publish its maximum staleness bound per action class and state source. This document does not impose one universal value. The following non-normative guidance illustrates freshness bounds that are likely to match the risk of common action classes: +================+=======================================+ | Class | Suggested freshness posture | +================+=======================================+ | Consequential | Token lifetime or a short state | | read | lease; tighter for privacy-sensitive, | | | cross-tenant, or bulk reads | +----------------+---------------------------------------+ | Consequential | A short state lease, typically | | write | measured in minutes | +----------------+---------------------------------------+ | Irreversible | Immediate check or single-use permit | | action | | +----------------+---------------------------------------+ | External | Immediate check or single-use permit | | commitment | | +----------------+---------------------------------------+ | Privileged | Immediate check, suitable for | | administration | composition with local step-up | +----------------+---------------------------------------+ Table 2 6. Parameter binding and time-of-check to time-of-use A permit for an operation does not authorize arbitrary parameter values. For consequential writes, irreversible actions, external commitments, and privileged administration, the PDP MUST bind its permit to the normalized action parameters through a parameter_digest, and the executing PEP MUST recompute and reverify that digest immediately before acting. * parameter_digest is sha-256: followed by the base64url, no padding, SHA-256 [RFC6234] of the JCS [RFC8785] serialization of the normalized parameter object. It MUST be computed under the same canonicalization rules the issuance profile defines (duplicate member rejection, significant array order, byte-for- byte URI comparison); this document does not define a second canonicalization. * The operation profile MUST define default insertion, omitted optional fields, and set-like array handling before canonicalization. * The permit MUST also bind the Mission reference, token issuer when available, token audience or protected resource, sub, client_id, actor context, sender-constraint confirmation key when present, action, resource, the authorizing authorization_details entry or an entry digest, the PDP's policy-view version, and a permit lifetime control bounded by the Mission state freshness requirement (Section 5.1). For a reversible consequential write, the control MUST be either a single-use decision identifier or a short validity window combined with an idempotency key that prevents repeat execution of the same normalized action. For an irreversible action, an external commitment, or privileged administration it MUST be a single-use decision identifier: a validity window alone does not bound how many times such a permit executes. * Where a single-use decision identifier is used, the enforcing component MUST record consumed identifiers for at least the permit lifetime and MUST refuse, fail closed, any second presentation of a consumed identifier. This is independent of consumption metering and applies even when the action carries no consumption bound. * The executing PEP MUST verify those bindings and MUST recompute the parameter_digest against the parameters it is about to use. A mismatch MUST cause refusal: the permit does not authorize the changed parameters. This closes the time-of-check to time-of-use gap and prevents a permit from being replayed for a different request (the parameter_digest mismatches). For non-idempotent consequential writes, irreversible actions, external commitments, and privileged administration, the single-use decision identifier or idempotency key also prevents repeat execution of the same normalized action. Consequential reads do not require a parameter digest by default; the evaluation request still appears in the evidence record, by digest where the parameters are sensitive (Section 9). Deployments MUST require parameter binding for consequential reads when read parameters materially change the effective resource set or disclosure risk. Examples include export-like or bulk reads, cross- tenant queries, privacy-sensitive filters, selected fields, destinations, and aggregation level. Ordinary reads that do not change the resource set or disclosure risk can remain unbound. 7. Consumption metering Consumption bounds the Mission carries are enforced here, not at issuance. The issuance profile ([I-D.draft-mcguinness-oauth-mission]) defines three Mission-level consumption bounds in the Mission context that this layer meters: * max_budget ({ amount, currency }): the PDP performs an atomic reserve-or-charge against the remaining balance for each consequential action and MUST refuse when the remaining balance is insufficient. * max_calls ([ { call_class, count } ]): the PDP increments an atomic counter for the named call_class and MUST refuse a call past count. * max_duration (an ISO 8601 duration, e.g. PT8H; the duration rule in Appendix A of [RFC3339]): the cumulative wall-clock duration of consequential activity under the Mission, as the issuance profile defines it (distinct from mission_expiry). The PDP accumulates the duration of consequential activity it reserves, commits, or permits and MUST refuse once that total would exceed the bound. For an action whose duration is not known before execution, the PDP MUST either reserve a bounded maximum duration or issue a duration lease that expires unless renewed; the PEP MUST stop the action or obtain a new permit before the reservation or lease is exhausted. After execution, the PEP MUST report the measured duration so the PDP can commit actual use and release any unused reservation. The operation profile defines how a single action's duration is measured so that PDPs accumulate consistently. A per-entry constraints value that expresses a consumption bound is metered the same way. When an applicable entry or the Mission's context carries such a bound, the PDP MUST meter use against it and MUST refuse a consequential action that would exceed it. The exactness of a consumption bound depends on the decision topology, and this profile does not overpromise: * Under a *single serializing PDP* for the Mission, the check and decrement can be atomic, and the bound is exact. * Under *multiple or distributed PDPs* (for example, Resource Server-hosted PDPs), an exact global counter is a distributed- counting problem. Such a deployment MUST publish the consistency bound it operates under (for example, per-PDP sub-budgets, or a bounded reconciliation window), and the effective guarantee is that bound, not exact-to-the-call enforcement. A deployment MUST NOT advertise exact consumption enforcement it cannot meet under its chosen topology. As with all constraints, an unmetered or unrecognized consumption bound MUST cause refusal rather than silent pass-through. For a metered permit, the PDP and PEP MUST define retry and idempotency behavior. A retry of the same normalized action under the same idempotency key or single-use decision identifier MUST NOT consume the bound twice. Reuse of an idempotency key or decision identifier for a different normalized action MUST cause refusal. For irreversible actions and external commitments, a deployment MUST define whether metering is reserved before execution and committed after success, or committed before execution; it MUST NOT leave the decrement ambiguous. 8. Failure modes Enforcement is meaningful only if failure is bounded. A PDP or PEP MUST behave as follows; in all cases the evidence record (Section 9) MUST be sufficient to reconstruct which path produced a refusal. +============================+================================+ | Condition | Required behavior | +============================+================================+ | Token validation fails, | Refuse before runtime Mission | | including sender- | evaluation | | constraint verification | | +----------------------------+--------------------------------+ | Mission governance is | Refuse before runtime Mission | | required but the token | evaluation | | lacks a mission claim | | +----------------------------+--------------------------------+ | PEP-PDP channel | Fail closed | | authentication or | | | integrity protection fails | | +----------------------------+--------------------------------+ | Mission state cannot be | Fail closed for consequential | | established within the | actions | | staleness bound | | +----------------------------+--------------------------------+ | PDP unreachable | Fail closed for consequential | | | actions; do not proceed on | | | cached permits past the window | +----------------------------+--------------------------------+ | Mission not active | Refuse | +----------------------------+--------------------------------+ | mission_expiry passed, | Refuse | | when known from the | | | Mission state source | | +----------------------------+--------------------------------+ | Unsupported | Refuse | | authorization_details type | | | for the action | | +----------------------------+--------------------------------+ | Unknown or unmetered | Refuse | | constraint on the | | | applicable entry | | +----------------------------+--------------------------------+ | Consumption bound would be | Refuse | | exceeded | | +----------------------------+--------------------------------+ | parameter_digest mismatch | Refuse | | at the executing PEP | | +----------------------------+--------------------------------+ | Re-presentation of a | Refuse (fail closed) | | consumed single-use | | | decision identifier | | +----------------------------+--------------------------------+ | Required act chain missing | Refuse | | or malformed | | +----------------------------+--------------------------------+ | Invoked capability | Refuse | | identity outside the | | | approved actions | | +----------------------------+--------------------------------+ | Resource policy refuses | Refuse | | the action | | +----------------------------+--------------------------------+ | Request would broaden the | Refuse (expansion is out of | | Mission's authority | scope) | +----------------------------+--------------------------------+ Table 3 9. Runtime enforcement evidence Every PDP decision on a consequential action MUST produce a runtime enforcement evidence record. A PEP refusal for a consequential action, whether before a PDP decision (for example, token validation failure or PDP unreachability) or after a PDP permit (for example, a parameter_digest mismatch), MUST likewise produce a runtime enforcement evidence record with the available fields and the failure condition. This document fixes the minimum record content and local integrity requirements. The concrete record schema, any interoperable canonical byte representation, separate Decision Evidence and Execution Evidence object schemas, and portable cross- domain receipts are out of scope (Section 11). 9.1. Required decision evidence A record MUST contain: * the decision or refusal result and, on refusal, the failure condition from Section 8; * the request time (RFC 3339 [RFC3339]); and * the parameter_digest for parameter-bound classes, or a privacy- preserving digest of the evaluation request otherwise. A record MUST also contain the following fields when they are available and trusted for the refusal or decision path: * the Mission reference (mission.id, mission.origin) and the authority_hash (and intent_hash when known: it is carried in neither the mission claim nor introspection, so it is available only to a PDP with direct Mission-record access, and most deployments record authority_hash alone) it operated under; * the token issuer and audience or protected-resource identifier when available; * the authenticated sub, client_id, a client-instance identifier (a deployment-defined correlator) when present, the sender-constraint confirmation key when present, and the act chain projection when delegation applies; * the action and resource identifiers (and the asserted capability identity when applicable); * the authorization_details type and authorizing entry, or a digest of that entry when recording the full entry would disclose excess authority or sensitive policy; * the decision identifier, when the PDP produced one; and * the PDP's policy-view version. For a token-validation failure, the record MUST NOT describe unverified token claims as authenticated facts. It MAY include a digest of the presented token or rejected claim set for correlation and forensics, subject to the privacy requirements below. The authority_hash and intent_hash in a record are the originating AS's commitments, cited as anchors; the PDP does not recompute them and is not required to hold the full Authority Set to record them, consistent with [I-D.draft-mcguinness-oauth-mission]. 9.2. Execution-outcome evidence For an irreversible action, an external commitment, or privileged administration, the executing PEP MUST also produce, after it acts, an execution-outcome record keyed to the permit's decision identifier, recording at least success or failure and the parameter_digest actually executed. This lets a decision and its execution be reconciled one to one, so a permit that was obtained but executed more than once, or executed for different parameters, is detectable after the fact. The detailed object schema is deferred (Section 11). 9.3. Record integrity and retention The following requirements apply to every record: * The Resource Server runtime profile MUST define the record's concrete serialization and canonicalization before storage and integrity protection. JSON records SHOULD use JCS [RFC8785] under the issuance profile's canonicalization rules. * It MUST be append-only and integrity-protected; the enforcement scope MUST name the mechanism (a hash-linked log, signed segments, a transparency anchor, or equivalent). * Raw parameters MUST NOT appear in the record; when retained for forensics they MUST be in separately access-controlled storage referenced by an opaque identifier, with only the parameter_digest in the record. * Records for one Mission MUST carry a deployment-defined sequence indicator so decision order can be reconstructed without relying on wall-clock time alone. * The enforcement scope MUST publish a retention window no shorter than the Mission's effective audit horizon. 10. Example decision API binding: AuthZEN The decision contract of Section 5 is abstract. One possible binding is the OpenID AuthZEN Authorization API [AUTHZEN]: the PEP issues an Access Evaluation request and the PDP returns a decision. This section is non-normative and does not define an AuthZEN profile. A deployment using AuthZEN can carry Mission and actor inputs in AuthZEN's open-ended context object: * context.mission: id, origin, authority_hash, and the current state. * context.actor: client_id, client-instance identifier when present, and the act chain as an array ordered root to leaf. The AuthZEN subject remains the principal the decision is requested for; the invoked capability is the action and the target resource is the resource. Note that AuthZEN's resource.type is a resource-kind identifier, not the issuance profile's authorization_details type ([I-D.draft-mcguinness-oauth-mission]): the example uses a deployment resource kind (mission_resource), and a deployment that needs to convey the mission_resource_access type carries it in resource.properties or context. An evaluation request might look like: { "subject": { "type": "user", "id": "user_3p2q8mN1a0kV7tR" }, "action": { "name": "journal-entries.write" }, "resource": { "type": "mission_resource", "id": "https://erp.example.com" }, "context": { "mission": { "id": "msn_8RfX2Lqv9TqMv4z7sA2bN1k0YpEdHc9-", "origin": "https://as.example.com", "authority_hash": "sha-256:l3KvZ4mP5x0wQrR6tY2nD9bM7sX1cF8gH2vJ4kE5pNQ", "state": "active" }, "actor": { "client_id": "s6BhdRkqt3", "act": [ { "sub": "tool-runner-7" } ] } } } On permit, the AuthZEN response carries the policy-view version, a decision identifier, the parameter_digest for parameter-bound classes, and a short validity window, for example: { "decision": true, "context": { "policy_view_version": "pv-2026-11-02-17", "decision_id": "dec_K9pV4nT2sR7mB1xQ", "parameter_digest": "sha-256:9XbVt2cF8gH2vJ4kE5pNQl3KvZ4mP5x0wQrR6tY2nD9", "expires_at": "2026-11-02T08:15:30Z" } } This profile's substance is the enforcement contract, action classification (Section 2.3), PEP placement (Section 2.4), parameter binding (Section 6), consumption metering (Section 7), and runtime enforcement evidence (Section 9), which is independent of the decision wire. The context.mission and context.actor example members above could be standardized separately as a Mission-bound AuthZEN binding without changing this contract. 11. Out of scope The following compose with this profile but are deferred to future work and are not required to enforce it: * mission expansion and the authority-expandable-denial escalation workflow (a deny here is terminal for the attempted action); * a standardized enforcement-scope manifest format and discovery mechanism; * cross-format capability-source binding (signed capability manifests, source-digest drift handling, cross-catalog identity); * portable, third-party-verifiable decision receipts (this profile fixes only the local runtime enforcement evidence record); * separate Decision Evidence and Execution Evidence object schemas and media types; * actor provenance beyond the act chain, attestation of the execution environment, and a purpose registry; * compilation of the Mission into an engine-native policy artifact (Cedar, OpenFGA, or equivalent) and standardization of PDP deployment modes; * action-hierarchy and resource-containment subset extensions (this profile uses the flat subset rule of [I-D.draft-mcguinness-oauth-mission]); and * risk-signal inputs to the decision (deployment-defined). Structured per-argument attenuation of tool grants ([I-D.draft-niyikiza-oauth-attenuating-agent-tokens]) is a related issuance/delegation-layer primitive, not part of this runtime profile. 12. Security Considerations 12.1. What this layer adds, and its limits Gating every consequential action against the current Mission prevents an active Mission from acting as ambient authority: authority is checked at the point of use, parameters are bound to the permit, consumption is metered, and each decision or refusal path is recorded. This closes the approval-to-execution gap the issuance profile leaves open. It does not make a compromised enforcement component safe. A compromised PEP can decline to consult the PDP or ignore its decision; a compromised PDP can return whatever decisions it chooses. Decision and enforcement evidence make such behavior auditable after the fact; they do not prevent it in the moment. Signed, externally verifiable decisions are future work (Section 11). 12.2. Placement and bypass The strongest decision logic is void if the PEP is not at the last controllable boundary, or if an unmediated path can reach the action (Section 2.4). A deployment's claim is only as strong as the set of execution paths it actually mediates; it MUST name that set. 12.3. Classification integrity Because "consequential" is partly deployment-defined, the classification floor of Section 2.3 is load-bearing: a deployment cannot evade enforcement by classifying an irreversible, external- commitment, or privileged-administration action as non-consequential. A purpose may raise a class but never lower it below the resource owner's floor. 12.4. Freshness and consumption honesty A permit is a lease, not a standing grant: stale Mission state MUST fail closed for consequential actions within the published bound (Section 5.1). Consumption bounds are exact only under a single serializing PDP; a deployment MUST NOT advertise exactness it cannot meet across distributed decision points (Section 7). 12.5. Resource policy remains authoritative Mission authority is a maximum authority envelope. It does not force a Resource Server to perform an action, bypass local authorization, or override object ACLs, tenant configuration, legal holds, service invariants, or risk policy. A runtime deployment that treats a Mission-bound permit as sufficient without Resource policy evaluation can perform actions that the resource owner or service would otherwise forbid. 12.6. TOCTOU and replay Parameter binding (Section 6) ties a permit to specific normalized parameters and a short window or single use, so a permit cannot be replayed for a different request or survive a parameter change between check and use. The executing PEP, not an upstream component, MUST perform the reverification. 12.7. Confused deputy across resources The permit binding of Section 6 ties a decision to the Mission, the token audience or protected resource, sub, client_id, actor context, action, and resource it evaluated. It follows that a PDP decision for one protected resource, audience, tenant, or operation is not reusable at another: the executing PEP, which reverifies those bindings before acting (Section 6), refuses a permit whose bindings do not match the boundary at which it is presented. A deployment MUST NOT relax those bindings in a way that would let a permit cross a resource, audience, tenant, or operation boundary it was not issued for. 12.8. Decision channel and token disclosure A separate PDP becomes part of the Resource Server's trusted authorization path for the operations in its enforcement scope. The PEP/PDP channel therefore needs mutual authentication, integrity protection, and authorization for the declared scope (Section 4). Passing full access tokens to a PDP also extends credential exposure beyond the Resource Server boundary; a deployment that does so needs the same credential handling, retention, and disclosure controls it applies at the Resource Server. 12.9. Evidence privacy and correlation Runtime enforcement evidence is intentionally durable and therefore sensitive. It can reveal a subject's resources, action timing, delegated actors, and Mission correlation identifier even when raw action parameters are not stored. Deployments SHOULD minimize recorded authority entries, store entry and parameter digests where full values are not needed for audit, restrict access to evidence by role, and document the retention window declared under Section 9. Evidence shared across resource boundaries can also correlate activity by mission.id and authority_hash; deployments that require unlinkability need an additional privacy design outside this profile. General OAuth security guidance [RFC9700] applies to the underlying credentials. 13. IANA Considerations This document has no IANA actions. The non-normative context.mission and context.actor example members of Section 10 are not registered in an IETF registry. The Mission-bound token claims this profile consumes are registered by [I-D.draft-mcguinness-oauth-mission]. 14. References 14.1. Normative References [I-D.draft-mcguinness-oauth-mission] McGuinness, K., "Mission-Bound Authorization for OAuth 2.0", Work in Progress, Internet-Draft, draft-mcguinness- oauth-mission, 2026, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet: Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002, . [RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms (SHA and SHA-based HMAC and HKDF)", RFC 6234, DOI 10.17487/RFC6234, May 2011, . [RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", RFC 6749, DOI 10.17487/RFC6749, October 2012, . [RFC6750] Jones, M. and D. Hardt, "The OAuth 2.0 Authorization Framework: Bearer Token Usage", RFC 6750, DOI 10.17487/RFC6750, October 2012, . [RFC7662] Richer, J., Ed., "OAuth 2.0 Token Introspection", RFC 7662, DOI 10.17487/RFC7662, October 2015, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8785] Rundgren, A., Jordan, B., and S. Erdtman, "JSON Canonicalization Scheme (JCS)", RFC 8785, DOI 10.17487/RFC8785, June 2020, . [RFC9068] Bertocci, V., "JSON Web Token (JWT) Profile for OAuth 2.0 Access Tokens", RFC 9068, DOI 10.17487/RFC9068, October 2021, . [RFC9700] Lodderstedt, T., Bradley, J., Labunets, A., and D. Fett, "Best Current Practice for OAuth 2.0 Security", BCP 240, RFC 9700, DOI 10.17487/RFC9700, January 2025, . 14.2. Informative References [AUTHZEN] OpenID Foundation, "OpenID AuthZEN Authorization API 1.0", 2025, . [I-D.draft-niyikiza-oauth-attenuating-agent-tokens] Aimable, N., "Attenuating Authorization Tokens for Agentic Delegation Chains", Work in Progress, Internet-Draft, draft-niyikiza-oauth-attenuating-agent-tokens-01, 15 June 2026, . Acknowledgments This document is the runtime companion to Mission-Bound Authorization for OAuth 2.0 and builds on the OpenID AuthZEN Authorization API and the OAuth 2.0 Rich Authorization Requests and JWT access token specifications. Author's Address Karl McGuinness Independent Email: public@karlmcguinness.com