Agent Capability Contract Open contract for A2B systems

RELEASE NOTES

Detailed compatibility and implementation notes for the ACC v1.0.3 Core and Binding architecture clarification release.

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ACC v1.0.3

ACC v1.0.3 is a compatible Core/Binding architecture clarification release for the ACC v1 declaration family.

Contract Version

ACC declarations continue to use:

x-agent-capability:
  version: 1

This release adds no released core field, changes no JSON Schema rule, and requires no declaration migration.

Core And Binding Architecture

ACC Core now has an explicit boundary from protocol-specific bindings:

  • Core owns the portable declaration fields, defaults, compatibility rules, and protocol-independent runtime invariants.
  • A binding owns declaration placement, operation identity, native input mapping, parameter-path resolution, metadata precedence, extraction failures, diagnostics, and binding-specific conformance evidence.
  • A validated capability artifact is defined as a conceptual interface between binding parsers and core runtimes, not as a required wire or storage format.
  • OpenAPI remains the first standardized ACC v1 binding; future bindings must preserve core semantics rather than redefine them.

These clarifications make future binding work possible without turning ACC Core into an OpenAPI-specific model.

OpenAPI Binding

OpenAPI-specific responsibilities are now consolidated in bindings/openapi.md, including:

  • operation-level x-agent-capability extraction;
  • standard parameters and requestBody preservation;
  • strict native-value mapping and condition-path resolution;
  • the OpenAPI GET readonly default and its precedence;
  • the relationship between OpenAPI descriptions, schemas, examples, and supplemental ACC guidance;
  • precise OpenAPI Binding Parser and Generator claim language.

No existing valid OpenAPI declaration changes meaning in this release.

Risk And Guidance Boundaries

The design rationale now records why detailed state-effect or business-domain taxonomies remain experimental authoring diagnostics, binding metadata, or future evidence-backed proposals rather than ACC v1 core fields.

guidance remains in the capability contract because an agent-facing capability must be selectable as well as governable. Binding-native request and response schemas remain authoritative, and guidance remains supplemental, non-authoritative, and non-security-critical.

Agent-Facing Deprecation Draft

The repository now contains a Draft Proposal for a minimal agent-facing deprecation signal. The draft deliberately does not define automatic sunset, disabling, redirection, argument migration, or replacement by scope.

The proposal is not part of released ACC v1. It has no effect on the v1 Schema or conformance corpus and cannot advance without independent implementation evidence and machine-readable vectors.

Conformance

Binding Parser and Generator claims must now name the binding they implement. Runtime and Policy Component profiles remain protocol-independent when they consume an equivalent validated capability artifact.

The ACC v1 corpus remains at 18 vectors. Existing inputs and expected outcomes are unchanged; wording now distinguishes portable bound-input behavior from OpenAPI-specific defaults, and the corpus release marker is updated to 1.0.3.