Agent Skills: Antfarm

Antfarm

Recon a large/unfamiliar codebase by fanning out cheap scout ants in parallel, then verifying with one stronger model. You are the moderator (main loop): you scope the query, partition the tree, dispatch scouts, run the verifier, and synthesize. The scouts and verifier are real subagents.

The point is context economy + coverage: scouts write verbose findings to scratchpad files in /tmp and return only short pointers, so exploring a huge tree never floods your context. Disjoint territories guarantee coverage without redundant reading. The verifier is the guardrail against cheap-model hallucination.

What this is for (scope)

Use when the codebase is too big to read into context and you need either (a) a map — structure, entry points, how subsystems connect — or (b) a needle — where X is implemented, where a behavior lives, which files touch Y. For small trees you can read directly, skip this; the orchestration overhead isn't worth it. User-invoked only; never auto-trigger.

Inputs

Query is $ARGUMENTS if provided, else the recon goal under discussion. Infer the mode from the query (state which you picked):

• Needle-hunt — "where is X / what touches Y / find the code that does Z." Scouts hunt their territory for matches; verifier confirms the hit(s) and rules out false positives.
• Survey — "map this repo / how does subsystem A work / what are the entry points." Scouts characterize their territory; verifier consolidates into a coherent map.

If the query is ambiguous about which, ask one clarifying question before dispatching.

Agents

Reuse the two model-pinned specialist defs (full model IDs, bypass the haiku alias remap):

• Scout ant → subagent_type: council-fast (Haiku 4.5) — cheap, parallel.
• Verifier → subagent_type: council-deep (Sonnet 5) — exactly one, after the barrier.

If a spawn fails with "agent type not found," the defs in ~/.claude/agents/ aren't loaded — tell the user to reload agents rather than silently falling back to a default model.

Scratchpad convention

Pick a short <slug> from the query (kebab-case, no spaces). All run artifacts live under /tmp/antfarm/<slug>/:

• Scouts write /tmp/antfarm/<slug>/scout-NN.md (NN = territory number).
• Verifier writes /tmp/antfarm/<slug>/report.md.

Create the directory before dispatching. If a slug collides with an existing run, suffix it so you don't read stale findings.

Protocol

1. Recon + partition (moderator, once)

Cheap structural scan only — do not read file contents yet. Use git ls-files, glob, or a shallow tree to see the top 1–2 levels and identify subsystems (dirs, packages, services, layers). Carve the tree into disjoint territories — every relevant path belongs to exactly one scout, no overlap. Scout count: up to 3, hard cap. Use fewer when the relevant surface is small (1–2 territories is fine); don't spawn vanity ants for empty territory. If there are more than 3 subsystems, group them into 3 balanced territories rather than adding scouts. State your territories + scout count + one-line rationale before dispatching.

2. Fan-out scouts (single message, barrier)

Spawn all scouts as named (name: = territory, e.g. scout-api) council-fast subagents in one message so they run in parallel. Give each:

• Its territory (explicit path set / globs) — and that it must stay within it.
• The query + mode.
• Its scratchpad path and the output contract below.

Scout charge / output contract:

• Write FULL findings to your scratchpad — files, symbols, line refs, how pieces connect, everything matching the query. Verbose is fine here; it's a file, not the moderator's context.
• Return to the moderator only: scratchpad path · a 3–5 line summary · confidence (low/med/high) · explicit uncertainty flags (guesses, unread files, things that look relevant but sit outside your territory). Do not paste full findings into the return.

3. Barrier

Proceed only after every scout has returned with content. A scout counts only if its result came back non-empty. If one is missing, re-dispatch it once; if it still drops, proceed and treat its territory as uncovered — report the gap. Never fabricate a dropped scout's findings; a hallucinated territory summary is the worst possible output.

4. Verify (one Sonnet pass)

Spawn a single council-deep verifier. Give it: the query + mode, the list of scratchpad paths, and the territory map. Verifier charge:

• Read every scout scratchpad, then spot-check claims against the actual repo — open the cited files/lines, confirm paths and symbols exist and say what the scout claims. Catch hallucinations, overreach, and gaps.
• Needle mode: confirm the located hit(s), rule out false positives, note any territory where the needle could hide but coverage was thin.
• Survey mode: consolidate scouts into one coherent map; reconcile contradictions between territories.
• Write the consolidated, verified result to report.md. Return: verdict (confirmed / corrections / gaps) · the synthesized answer · confidence · a coverage assessment (territories with weak or no coverage).

Do not spawn a verifier per scout — it's one pass over the consolidated findings.

Report (moderator)

Deliver, in order:

1. Answer — the verified map or located needle, synthesized from report.md.
2. Corrections — anything the verifier overturned in the scouts' claims (kept visible, not memory-holed).
3. Coverage — territories explored, scout count, and any uncovered/thin areas (dropped scouts, low-confidence zones) so the user knows the blind spots.
4. Artifacts — the /tmp/antfarm/<slug>/ path, for follow-up.

Rules

• Cost hygiene: scouts are Haiku (cheap); one Sonnet verifier. Scale scouts to real subsystems, not a target number. Don't use Monitor — background-agent completions notify you automatically. Don't load extra tools mid-run.
• Disjoint territories: overlap wastes the parallelism. If subsystems are entangled, split by responsibility, not by overlapping paths.
• The verifier is a skeptic, not a rubber stamp — its job is to break the scouts' claims, not bless them. Cheap-model findings are unverified until it confirms them.
• Context discipline: scouts' verbose output stays in scratchpads. If you find yourself with full file dumps in your context, the pattern failed — re-dispatch with a tighter return contract.

Maintenance — pinned models

The seats pin full model IDs (in ~/.claude/agents/council-{deep,fast}.md, shared with the council skill) to bypass the user's ANTHROPIC_DEFAULT_HAIKU_MODEL alias remap. Full IDs do not auto-upgrade and will break/degrade when the model is retired.

• council-fast (scout) → claude-haiku-4-5-20251001
• council-deep (verifier) → claude-sonnet-5
• Pinned: 2026-07. Re-check when a new Sonnet/Haiku ships or these EOL — bump the IDs in those two defs.