The four tools have largely distinct purposes: derive_route_shard computes a shard, parse_envelope does structural decoding, verify_envelope does cryptographic verification, and published_vector returns a test fixture. parse_envelope and verify_envelope both operate on the same 128-byte envelope, which could momentarily confuse an agent, but the descriptions clearly separate 'structural, no key' from 'HMAC verification with organ_key'.

Three tools follow a clean verb_noun snake_case pattern (derive_route_shard, parse_envelope, verify_envelope) with consistent imperative verbs. The fourth, published_vector, is a noun phrase rather than a verb_phrase, a minor deviation from the otherwise predictable convention.

Four tools is a tight, well-scoped surface for a narrow cryptographic verification domain (derive, parse, verify, plus a self-test vector). It leans slightly thin, but each tool clearly earns its place with no redundancy.

The surface covers the full verify-a-lifecycle: deriving the intent shard, decoding the envelope, verifying it, and a published conformance vector for offline self-testing. The main gap is the absence of an encode/build or key-generation counterpart, though that may be intentionally out of scope for a stateless verifier.