[CAP] Charter Agreement Protocol
CAP is a portable, non-authorizing format and verification protocol for bilateral commercial agreements: signed, byte-exact artifacts that prove what two parties agreed, which revision governed a given instant, and which agreement state governed a signed action — without a central authority, and without ever making the decision for you. CAP verifies. It never authorizes.
Each one is bytes you can hand to anyone; each one proves exactly what it says and nothing else.
| Artifact | Form | Proves |
|---|---|---|
| Party Descriptor | signed JWS (cap+party) | a party’s declared key history — Ed25519, and ML-DSA from revision 3 — with predecessor-bound transitions and fork evidence |
| Charter Revision | canonical JSON | agreed terms: parties, roles, legal-text digest, precedence, window, termination reasons, exact deployment bindings |
| Acceptance | signed JWS (cap+acceptance) | bilateral signed assent to exact revision bytes |
| Termination Notice | signed JWS (cap+termination) | signed closure of the charter at a pure UTC instant |
| Receipt | signed JWS (cap+receipt) | a signed action bound to exact revision coordinates, deployment digest, and grant evidence |
The refusal list is the product. A verification tool that quietly makes your business decisions for you is not a verification tool.
term_satisfaction stays in the omission floorTwo systems, two “version 2”s — and a dispute nobody can settle from the bytes.
Strict unpadded base64url, deterministic tagged decoding, RFC 8785 canonicalization, domain-separated SHA-256 — acceptances bind exact bytes.
Most tooling silently tie-breaks an equivocation and calls it a verdict.
Same-signer equivocation is retained as signed evidence with no winner; the only repair is a countersigned supersession revision.
One implementation verifying itself proves nothing about the spec.
A certified 100-case corpus runs through the pure Elixir verifier and a builtins-only TypeScript one — byte-identical canonical reports or the build fails.
Three protocols, one chain of evidence: what the agent is, what was agreed, what this call may do.
One protocol, four repositories, two ecosystems — same bytes everywhere, live demos on the TypeScript sites.
The Elixir reference implementation and verifier, the certified corpus, the spec and guides — including the security model’s full proves/never-proves table.
The npm companion that produces the signed artifacts through a caller-owned key handle — the private key never enters the library.
The npm verify side: byte-exact artifact decode, chain facts, the algorithm registry — zero runtime dependencies, corpus-certified.
The Elixir holder-side companion — the reference this TypeScript signer ports; {module, term()} custody, one dependency: this protocol package.