quality-gate

Quality Gate Generator

Generate or update scripts/harness/quality_gate.sh for the current project.

Process

1. Detect the project's tech stack
2. Select appropriate checker(s):
   • TypeScript → npx tsc --noEmit
   • Rust → cargo check
   • Go → go vet ./...
   • Python → mypy or pyright
   • JavaScript → npx eslint .
3. Generate the quality gate script with infinite-loop prevention
4. Ensure it's wired as a Stop hook in .claude/settings.json

Key Requirements

• MUST check stop_hook_active payload 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

Backpressure Output Pattern

• On success: print only "Harn: Quality gate passed." (minimal output)
• On failure: print the full error log to stderr (full output)