fortify

Ablation study runner — after /research:run finds improvements, fortify identifies which components contributed, generates ablation variants (remove one component at a time), runs each in isolated git worktrees (main repo never modified), ranks component importance, optionally generates reviewer Q&A calibrated to venue.

NOT for: initial optimization loop (use /research:run); methodology validation (use /research:judge); paper-vs-code consistency (use /research:verify); hypothesis generation (use research:scientist directly). Fortify runs ablation studies on completed runs only.

MAX_ABLATION_CANDIDATES:  8 (ceiling — scientist produces 3–8; --max-ablations caps further)
METRIC_TIMEOUT_MS:        360000 (6 min — deliberately larger than run's 120s/300s VERIFY_TIMEOUT_SEC, to accommodate slower ablation-variant runs)
GUARD_TIMEOUT_MS:         360000
GIT_OP_TIMEOUT_MS:        15000
SANITY_DIVERGENCE_PCT:    2.0 (full-variant vs best_metric mismatch threshold)
IMPORTANCE_CLASS_CRITICAL: 50.0 (% of full metric lost)
IMPORTANCE_CLASS_SIGNIFICANT: 10.0
FORTIFY_DIR_BASE:         .experiments
STATE_DIR_BASE:           .experiments/state
METRIC_CMD_SOURCE:        state.json .config.metric_cmd (campaign's real metric — no fail-open default; env METRIC_CMD overrides)
GUARD_CMD_SOURCE:         state.json .config.guard_cmd (campaign's real guard — no fail-open default; env GUARD_CMD overrides)

Environment overrides — set these before invoking the skill to override per-variant defaults:

• METRIC_CMD — command run inside each variant worktree to measure the ablation metric (override; default sourced from source-run state.json .config.metric_cmd)
• GUARD_CMD — command run inside each variant worktree to detect regressions (override; default sourced from source-run state.json .config.guard_cmd)
• STATE_DIR_BASE — base directory for source-run state lookups (default: .experiments/state)
• FORTIFY_DIR_BASE — base directory for per-run fortify artifacts (default: .experiments)

The constants block defaults above are YAML-only — bash blocks read environment variables (with ${VAR:-default} fallback) and never source values directly from YAML.

• Key boundaries: end of F2 — ablation candidates identified by scientist; end of F4 — all ablation variant worktrees completed.
• Preserve at F2: FORTIFY_DIR (TMPDIR key), RUN_ID (TMPDIR key), ablation-candidates.jsonl path, best_metric from source run.
• Preserve at F4: FORTIFY_DIR, RUN_ID, results.jsonl path — ready for F5 importance ranking.
• F4 loop is resume-safe: 4a-init's resume guard skips variants already terminal (non-timeout) in results.jsonl, so a mid-loop compaction resumes at the first pending variant — never re-runs a completed ablation; a timed-out variant still retries.
• Clear at F1 start (stale prior run) and at start of F8 terminal summary.

Agent Resolution

Agent resolution: load and follow the protocol below. Contains foundry check + fallback table. If foundry not installed: use table to substitute each foundry:X with general-purpose. Agent this skill dispatches: research:scientist (same plugin — no fallback if research plugin installed).

# loads: compaction-contract.md
export CSID="${CLAUDE_CODE_SESSION_ID:-$PPID}"
_RESEARCH_SHARED=$(python "${CLAUDE_PLUGIN_ROOT:-plugins/cc_research}/bin/resolve_shared.py" 2>/dev/null)  # timeout: 5000
[ -z "$_RESEARCH_SHARED" ] && { echo "! Plugin path resolution failed — ensure research plugin installed and CLAUDE_PLUGIN_ROOT set, or invoke /research:fortify from project root."; exit 1; }
echo "$_RESEARCH_SHARED" > "${TMPDIR:-/tmp}/research-shared-${CSID}"  # cold resolve — every later site reads this sentinel instead of re-running python
cat "$_RESEARCH_SHARED/agent-resolution.md"

Agent	Fallback if absent
research:scientist	general-purpose (ablation candidate identification and reviewer Q&A quality reduced — ⚠ general-purpose agent may not emit the JSON envelope this skill parses; surface partial output and surface ⚠ in F7 report)