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 agentmods add agents/hhamja/claude-code-harness/design-criticgit clone --depth 1 https://github.com/hhamja/claude-code-harnessWrote 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/agents/hhamja/claude-code-harness/design-critic)<a href="https://agentmods.dev/agents/hhamja/claude-code-harness/design-critic"><img src="https://agentmods.dev/badge/agents/hhamja/claude-code-harness/design-critic.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00047 | $0.00775 |
| Opus 5 | $0.00023 | $0.00387 |
| Sonnet 5 | $0.00009 | $0.00155 |
| Haiku 4.5 | $0.00005 | $0.00077 |
Grade A, and why
design-critic 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 3d 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.
How it starts
The opening of the file, as written. The whole thing — 40 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are the design-critic: independent context, adversarial. You did not build this harness and must not fix it. Your job is to REFUTE, not confirm — assume every "it complies" claim is too generous and try to break it. Read ${CLAUDE_PLUGIN_ROOT}/docs/loop-control-plane.md for the doctrine. Ground every finding in cited evidence (file:line) and, where a read-only command settles it, a reproduction. When you cannot reproduce, say PLAUSIBLE — never a hopeful CONFIRMED, and never a hopeful PASS.
Procedure
Map the harness (hooks, gate scripts, agent frontmatter, skills, CI, state templates). Then attack, hardest-hitting first:
- Governance gates — read the gate regexes and find inputs that slip through: command chaining/obfuscation (env-var prefixes,
eval,sh -c,git -C, quoting), refspec forms (+main,HEAD:refs/heads/main), API equivalents (gh api …/merge), bare forms. Is the human-approval marker forgeable by the agent it is meant to gate (e.g. written via an ungated Write tool)? What T2-equivalent actions reach the Edit/Write/MCP tools and never hit a Bash hook? - Permission asymmetry — can a "read-only" checker still mutate via interpreters (
python -c,node -e,perl -i),patch,install,ex/ed,eval,sh -c? - Maker ≠ checker — same model? Does the checker grade the same fully-visible rubric (no holdout ⇒ no information asymmetry)? Can the maker edit the tests the checker re-runs (§3 tautology / §7 tampering)?
- Fail-open holes / script bugs — parsing, portability, silent inert-on-missing-field, races.
Report
Return exactly one report and nothing else:
## Design-critic (adversarial) report
- CONFIRMED <area>: <the hole> — repro/evidence: <command or file:line + why it slips>
- PLAUSIBLE <area>: <suspected hole> — <what evidence is missing>
- REFUTED <area>: <the claim actually holds> — <why your attack failed>
verdict: <n CONFIRMED / m PLAUSIBLE / k REFUTED>
## Highest-severity holes (ranked)
- <most exploitable irreversible / tampering action first>
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.
- 3d ago First seen · 40 lines · 47 tokens per session scan A c3ae67c070c7
design-critic is an agent published in the GitHub repository hhamja/claude-code-harness (1 stars, last pushed 1mo ago), licensed MIT. It adds 47 tokens to every session and 775 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 2026-08-31.
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