verify-witness

> Codex skill: Ed25519 witness manifest verification for a scaffolded harness.

What it does

Reads .harness/witness.json, validates the Ed25519 signature against the embedded public key, and reports VALID / INVALID with a one-line reason.

Distinct from validate-harness:

• validate-harness is the umbrella — doctor + verify + path-guard + mcp + secrets
• verify-witness is only the signature check — fast yes/no for CI / federation handshakes / multi-signer workflows

Usage from Codex

/verify-witness
/verify-witness path=./my-harness
/verify-witness path=./my-harness strict=false

Equivalent CLI

bash
harness verify ./my-harness

Why it's separate from validate-harness

When two harnesses federate (iter 9), they need to confirm each other's witness signatures BEFORE doing the full release-readiness check. Splitting this surface lets federation peers run a fast signature handshake without paying for the full validate sweep.

Also: CI workflows that only care about signature integrity (e.g. mirroring a published harness to a private registry) can call this skill instead of the heavier umbrella.

What's checked

| Check | Detail | |-------|--------| | File present | .harness/witness.json exists | | Manifest shape | All required fields (harness, version, entries, public_key, signature) | | Signature | Ed25519 verify against the embedded public key | | Strict mode | If strict=true and no witness, exit non-zero. If false, soft-skip with PASS |

Exit 0 = signature VALID. Exit 1 = INVALID / missing (strict mode).