Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add ruvnet/metaharness --skill verify-witnessgit clone --depth 1 https://github.com/ruvnet/metaharnessWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/ruvnet/metaharness/verify-witness)<a href="https://agentmods.dev/skills/ruvnet/metaharness/verify-witness"><img src="https://agentmods.dev/badge/skills/ruvnet/metaharness/verify-witness/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/ruvnet/metaharness/verify-witness"><img src="https://agentmods.dev/badge/skills/ruvnet/metaharness/verify-witness.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00045 | $0.00435 |
| Opus 5 | $0.00023 | $0.00217 |
| Sonnet 5 | $0.00009 | $0.00087 |
| Haiku 4.5 | $0.00005 | $0.00044 |
Grade A, and why
verify-witness scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
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-harnessis the umbrella — doctor + verify + path-guard + mcp + secretsverify-witnessis 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
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).
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 12d ago First seen · 48 lines · 45 tokens per session scan A 807527b6526c
verify-witness is a skill published in the GitHub repository ruvnet/metaharness (645 stars, last pushed yesterday), licensed MIT. It adds 45 tokens to every session and 435 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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