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 skills/sliday/harn/quality-gatenpx skills add sliday/harn --skill quality-gategit clone --depth 1 https://github.com/sliday/harnWhat 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 | $0.00039 | $0.00963 |
| Opus 5 | $0.00019 | $0.00481 |
| Sonnet 5 | $0.00008 | $0.00193 |
| Haiku 4.5 | $0.00004 | $0.00096 |
Grade A, and why
quality-gate 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 2d 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 — 115 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Quality Gate Generator
Generate or update scripts/harness/quality_gate.sh for the current project.
Process
- Detect the project's tech stack
- Select appropriate checker(s):
- TypeScript →
npx tsc --noEmit - Rust →
cargo check - Go →
go vet ./... - Python →
mypyorpyright - JavaScript →
npx eslint .
- TypeScript →
- Generate the quality gate script with infinite-loop prevention
- Ensure it's wired as a Stop hook in
.claude/settings.json
Key Requirements
- MUST check
stop_hook_activepayload to prevent infinite loops - MUST output errors to stderr (fed back to agent)
- MUST exit 2 to block, exit 0 to allow
- Should complete in under 30 seconds
Generated Script Template
The generated scripts/harness/quality_gate.sh must include the following robustness patterns:
KB References (at top of script)
# Harn quality gate — blocks agent completion if code is broken
# Why: https://harn.app/kb/safety.html — "Quality checks in the loop"
# Pattern: https://harn.app/kb/evals.html — "Infrastructure noise moves benchmarks"
Dependency Checks (before any checker runs)
command -v jq &>/dev/null || { echo "Harn: jq not found, quality gate skipped" >&2; exit 0; }
Session-Aware Temp File (replaces /tmp/harn_gate.log)
LOG_FILE="${TMPDIR:-/tmp}/harn_gate_${PPID}_$$.log"
Checker Guards (verify tool exists before running)
Each checker must be guarded with command -v before invocation:
if [ -f "tsconfig.json" ]; then
command -v npx &>/dev/null || {
echo "QUALITY GATE BLOCKED: TypeScript detected but 'npx' not found." >&2
echo "Install Node.js or remove tsconfig.json." >&2
exit 2
}
npx tsc --noEmit > "$LOG_FILE" 2>&1 || {
echo "QUALITY GATE BLOCKED: TypeScript errors found:" >&2
cat "$LOG_FILE" >&2
exit 2
}
fi
if [ -f "Cargo.toml" ]; then
command -v cargo &>/dev/null || {
echo "QUALITY GATE BLOCKED: Rust detected but 'cargo' not found." >&2
echo "Install Rust toolchain or remove Cargo.toml." >&2
exit 2
}
cargo check > "$LOG_FILE" 2>&1 || {
echo "QUALITY GATE BLOCKED: Cargo check errors found:" >&2
cat "$LOG_FILE" >&2
exit 2
}
fi
if [ -f "go.mod" ]; then
command -v go &>/dev/null || {
echo "QUALITY GATE BLOCKED: Go detected but 'go' not found." >&2
echo "Install Go or remove go.mod." >&2
exit 2
}
go vet ./... > "$LOG_FILE" 2>&1 || {
echo "QUALITY GATE BLOCKED: Go vet errors found:" >&2
cat "$LOG_FILE" >&2
exit 2
}
fi
if [ -f "mypy.ini" ] || [ -f "setup.cfg" ] || [ -f "pyproject.toml" ]; then
command -v mypy &>/dev/null || {
echo "QUALITY GATE BLOCKED: Python type checking configured but 'mypy' not found." >&2
echo "Install mypy or remove type checking config." >&2
exit 2
}
mypy . > "$LOG_FILE" 2>&1 || {
echo "QUALITY GATE BLOCKED: mypy errors found:" >&2
cat "$LOG_FILE" >&2
exit 2
}
fi
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.
- 2d ago First seen · 115 lines · 39 tokens per session scan A d048c0636770
quality-gate is a skill published in the GitHub repository sliday/harn (5 stars, last pushed 4mo ago), licensed MIT. It adds 39 tokens to every session and 963 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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