Conformance

How CAP proves — to two independent implementations, under deliberate defects, and against the exact bytes that would be published — that the protocol you read about is the protocol you run.

The certified corpus

The shipped corpus (priv/conformance, included in the package archive) contains 85 certified cases across 14 case files, covering every compiled applicability surface: foundational codecs (base64url, JSON, canonicalization, digests), schema validation, party descriptors, descriptor chains, charter revisions, acceptances and equivocation, terminations, chain verification, governing revision, and receipts — including fork, quarantine, and profile cases. Completion is by obligation, not count: every required applicability cell has executed cases, every not-applicable cell carries a non-empty reason, and counts must equal observations.

The corpus is self-digesting. Loading (Conformance.Corpus.load/1, pure — a complete map of relative path to bytes, no file I/O) requires canonical index and case bytes, a recomputed domain-separated corpus digest, exact declared/observed file-set equality with per-file SHA-256 hashes, exact counts, globally unique case IDs, and projected outputs for valid cases — a verdict-only green is refused, so a runner that says "valid" without producing the exact expected fact document cannot pass.

The certified identities

The release-candidate ADR separates these jobs:

• corpus_digest — the domain-separated digest inside the canonical corpus index. Proves the index is self-consistent.
• index_sha256_base64url — the raw SHA-256 of the exact canonical index bytes. Pinned by the Elixir CLI, the independent TypeScript verifier, and the packaged release metadata. Proves the candidate is the reviewed corpus, not merely a newly self-consistent one.

For the current candidate:

The requirements matrix

Every public requirement carries a stable CAP-<SURFACE>-<kebab-tag> identifier (see the errata policy) and compiled evidence routing in CharterAgreementProtocol.RequirementMap: corpus cells, architecture gates, and — for the closed mutation battery — named red-capable source mutations. spec/requirements.md is generated from that map (mix run scripts/render_requirements.exs). mix conformance.verify rejects a stale render and enforces bidirectional coverage: every requirement carries evidence, and every corpus cell and named mutation is bound to at least one requirement. The generated matrix carries the exact live counts; the closed mutation battery is bound one-to-one to the requirements that name it.

The CLI

$ charter_agreement_protocol --corpus DIRECTORY

Exit 0 — every certified case recomputed and agreed; the canonical JSON report on stdout carries per-case actual and expected documents, agreement counts, and all three report identities. Exit 1 — load or verification failure. The fourth certified identity — the specification digest — is pinned in the release metadata and enforced by the release-candidate gate. Exit 2 — usage. The CLI is the sole filesystem adapter (≤ 64 files, ≤ 32 MiB) and refuses any corpus whose raw index identity is not the certified pin — including a freshly regenerated, internally consistent one.

The gate battery

mix quality runs everything below plus audits, formatting, warnings-as-errors compile, strict credo, the full test suite with its coverage threshold, dialyzer, and docs:

• mix conformance.verify — runs the certified corpus and regenerates the core cases in a scratch directory, requiring byte identity with the certified corpus. A closed set of supplemental cross-package and profile cases (frozen at their owning boundaries — the exact ABP 0.1.1 deployment and BAP 0.1.2 grant vectors) stays frozen and required. The same gate proves the requirements matrix is fresh and bidirectionally covering, and enforces the wire grammar schemas.

Wire grammar schemas

spec/schemas/ is the single normative machine grammar for every externally consumed wire format: the five artifact claim sets, the extension envelope, the compact-JWS protected header, the tagged-digest and timestamp grammar, and the corpus index and canonical report documents. Every schema is JSON Schema 2020-12 restricted to the closed 16-keyword subset validated by the pinned AgentBlueprintProtocol.Schema — no other dialect file exists and no new dependency is introduced. Character-set shape, byte-exact bounds, cross-field rules, and conditional member presence stay codec-enforced and normative in the spec text; the schema layer expresses member closure, types, enumerations, ranges, and cardinalities (see the schema README).

The gate proves both directions: every valid corpus artifact (claim sets, protected headers, revision texts, the shipped index, and the live canonical report) validates against its schema, and each shipped constraint carries a constructed single-defect negative observed to fail. Two completeness floors keep the set honest against drift — each artifact schema must declare exactly the member and required sets of the codec definition it serves, and every properties-bearing schema object must be closed. The extended conformance.verify completes in ~1.7s against a 3s budget.

• mix conformance.mutations — creates isolated scratch copies and proves all 22 named source defects go red: JCS number defeat, padding acceptance, separator collapse, unknown-member acceptance, chain signature skip, digest equality skip, Ed25519 defeat, typ confusion, reason-code uncheck, precedence collapse, facts-union suppression, fork-topology suppression, contested tie-resolution, equivocation guard removal, receipt conflict silencing, and more — with corpus-expectation-flip running last. Each run first proves the unmodified baseline green.
• mix verifier.agreement — the builtins-only Node 24+ TypeScript verifier independently recomputes every certified case (including Ed25519 evidence, forks, supersession, governing views, receipt fact JSON) and must produce reports byte-identical to the Elixir runner over both the repository corpus and the corpus unpacked from the Hex archive. Directional seeded reds (verdict inversion, report-format drift, certified-index drift) prove the comparison can fail.
• mix release.candidate — verifies canonical release metadata, all three certified identity pins inside the CLI and the TypeScript verifier core, development/test-only dependency direction, regular-file package inputs, two independently built byte-identical archives, and exact unpacked archive membership.

Cryptographic known answers

The SHA-256 gate uses current NIST CAVP byte-oriented vectors (empty input, d3, b4190e) under FIPS 180-4. These verify the runtime primitive against published answers; they do not claim CAP has undergone CAVP validation.

Changing the corpus deliberately

scripts/record_conformance_index.exs is the full-corpus index recorder after a deliberate case change. Any corpus, registry, report, or package-boundary change invalidates the recorded identities and requires re-running conformance, all named mutations, verifier agreement, package verification, review, and hosted CI. Verdict-changing corrections to a published protocol follow the errata policy.