bughunt

A bug hunt prompt tells the model to prove a bug before it fixes it, and the model often writes the fix first and a test that passes after. This mod runs the hunt in rounds and holds each round to its proof. The model writes a proof command, the mod runs it itself, and production code stays unchanged until the proof exits non-zero with a FAIL line. The round counts as fixed only when the same command then exits 0 with a PASS line, and fails again once the mod reverts the fix for a moment. The loop reads each round's outcome and stops at a blocked or unverified round instead of starting the next one.

/bughunt collab <paths> is a second, read-only mode: a scanner, a planner and a critic subagent review the paths in turn, and the report carries the findings, the plan and the critic's verdict.

What it does

Rounds

1. /bughunt [--rounds N] [target] starts a hunt of 1 to 25 rounds over the target, or over the whole project. --rounds may stand anywhere among the arguments. The hunt starts at any point of the session.

2. The mod sends each round as a prompt: the round number, the scope, the round's proof directory (.temp_files/bughunt/<round>/), the fingerprints of the earlier rounds and the protocol. The model first opens the bughunt:hunt skill, which holds the full rules; while a round runs, the mod appends the round's block to the skill's text.

3. While a round runs:

   • Edit, Write and NotebookEdit stop until the skill is open in the round.
   • An edit outside the proof directory stops until the mod recorded a FAIL.
   • With a target, an edit outside it stops after the FAIL too. A test file (tests/, __tests__/, *.test.*, *.spec.*, *_test.*, test_*.py) passes, so the regression test can go into the suite.
   • Every subagent spawn stops: a round runs in one conversation.

4. The model calls mcp__bughunt__proof with phase: "before" and the proof command's argv. The mod runs the command (5 minutes at most) and records FAIL only when it exits non-zero and prints a line that starts with FAIL. A setup or import error that prints no such line is rejected. After the fix, phase: "after" with the same argv runs the command again and needs exit 0 and a line that starts with PASS. The model reads the exit code, the last 20 lines of output and the reason.

5. Before it records the PASS, the mod checks that the proof reaches the fix. When the FAIL was recorded, it took a snapshot of the working tree (git stash create, which adds no stash entry, or HEAD on a clean tree). After an accepted PASS run it lists the files modified since that snapshot (git diff --diff-filter=M), leaves out the proof directory and test files, and restores them to the snapshot in the working tree (git restore --source, the index stays as it was). It runs the proof again and then puts the fix back. The PASS counts only when that reverted run exits non-zero with a FAIL line. Otherwise the call is rejected and the model can fix the proof and call again. The model reads the reason in each case:

   • the proof passes with the fix reverted, so it does not reach the fixed code;
   • no production file was modified since the FAIL;
   • the directory is not a git repository;
   • a git command failed.

   While the fix is reverted, the mod keeps a record in $.store. When a crash cuts the check short, the next session in the same directory puts the fix back, if the reverted files are still unchanged. If they changed since, it does not overwrite them and tells you the git restore command that brings the fix back.

6. When the round's turn ends, the mod reads the answer's outcome line: the first line that begins with an outcome label, so a sentence before it does not hide it:

   • fixed-and-verified goes on only when the mod recorded FAIL then PASS in the round; otherwise the hunt stops.
   • no-proven-bug goes on.
   • blocked, fixed-verification-incomplete, no outcome line, an interrupt or an API error stop the hunt.
   • After the last round the hunt ends.

   The fingerprint: line of each answer goes into the next rounds' prompts, so the same root cause is not counted twice.

7. A prompt you write yourself ends the hunt; /bughunt commands do not.

Collab

1. /bughunt collab <paths>, or the model's mcp__bughunt__collab tool, starts three subagents in turn. They are the mod's own agent types (bughunt:scanner, bughunt:planner, bughunt:critic), hidden from the model's agent list, and each can only read: Read, Grep, Glob.
2. The scanner reports each finding at once with mcp__bughunt__found (file, line, severity, description, optional fix). The mod checks the fields and keeps the finding. Only the running scanner may call the tool.
3. The planner receives the findings and the scanner's report, and writes a fix plan. The critic receives the findings and the plan, and begins its answer with verdict: approve, revise or reject.
4. Each step has a time limit (scanner 10, planner 8, critic 6 minutes). A step that runs out is named in the report as timed-out, and the findings the scanner sent before that stay in the report.
5. When the critic gives no verdict line, the verdict is no-verdict, never approve.
6. The command and the tool return once the scanner started; the report arrives later as one message, and the model reads it as a read-only review. A step's hand-back message is taken by the mod and dropped, so it does not start a turn of its own.
7. A collab does not start while a round runs.

What you see

The sidebar shows a standing bughunt section: the round, whether the skill is open, the proof state and each finished round's outcome and fingerprint. Stopped edits, proof results and the hunt's end go to the sidebar stream. Without the sidebar, each of them is one transcript line such as bughunt: edit stopped (proof): src/a.ts.

Command

/bughunt [--rounds N] [target]    start a hunt of N rounds (1 by default, 25 at most)
/bughunt collab <paths>           a read-only scanner, planner and critic review
/bughunt stop                     end the running hunt
/bughunt status                   on or off, and the running round
/bughunt on | off                 on by default; off starts nothing and holds no edit

Install

claude plugin marketplace add KilimcininKorOglu/claude-code-mods
claude plugin install bughunt@kilimcininkoroglu-mods

Function hooks are early access. Claude Code 2.1.288 and later load them by default, so there is nothing to switch on.

After installing

1. Restart Claude Code.
2. Run /bughunt in a repository whose tests you can run from the command line. The proof command runs with your permissions, so read what the model proposes.

What it can reach

Validated with claude plugin validate on Claude Code 2.1.284:

❯ ./register.ts hooks: session.start, command.run{command=bughunt}, agent.offer{agent=/"^bughunt:(scanner|planner|critic)$"/}, tool.describe{tool=/"^mcp__bughunt__(proof|found|collab)$"/}, tool.call{tool=/"^mcp__bughunt__proof$"/}, tool.call{tool=/"^mcp__bughunt__found$"/}, tool.call{tool=/"^mcp__bughunt__collab$"/}, prompt.submit, skill.prompt{skill=bughunt:hunt}, tool.call{tool=Skill}, tool.call{tool=Edit}, tool.call{tool=Write}, tool.call{tool=NotebookEdit}, agent.spawn, turn.complete
❯ ./register.ts calls: $.agent.register (via declare), $.agent.spawn (via portsOf), $.clock.after (via portsOf, send), $.command.register (via declare), $.command.run (via send), $.process.run (via git, recoverFix, runProof), $.prompt.submit (via send), $.sidebar.clear (via show), $.sidebar.set (via show, toPerson), $.store.delete (via putBack, recoverFix), $.store.get (via readSettings, recoverFix), $.store.set (via revertCheck, setEnabled), $.tool.register (via declare), $.ui.log (via launchCollab, send, toPerson)

Reach L2, it runs the proof command the model names.

1. Reads:    the path of each Edit, Write and NotebookEdit call; your prompts, only to see whether you wrote one; each round's final answer; the collab subagents' answers
2. Runs:     the proof command the model passes to mcp__bughunt__proof, as argv without a shell, in the working directory or the cwd it names, for 5 minutes at most, a second time with the fix reverted; git stash create, rev-parse, diff and restore --worktree in the working directory for that check; three read-only subagents for a collab
3. Sends:    each round's prompt and each collab report to the model as a message, a deny text for a stopped edit or spawn, the round's block after the skill's text, sidebar sections and lines or transcript lines to you; nothing leaves the machine
4. Persists: in $.store, the on/off setting, and while a revert check runs the snapshot that holds the fix and the reverted files; the hunt itself lives in memory and ends with the session
5. Hostile input: the proof command is the model's and runs with your permissions, as a Bash call would, but without a shell; a finding's fields are checked before they are kept

Limits

• The gate reads Edit, Write and NotebookEdit. A file changed through Bash (sed -i, a redirect, a script) is not held.
• The revert check shows that the proof depends on the files the fix modified. It cannot tell whether the proof asserts the right behaviour.
• The revert check reverts only tracked files the fix modified. A fix that only adds files has nothing to revert, so its PASS is rejected. Outside a git repository, no PASS is recorded.
• While the check runs (at most one more proof run), the fixed files hold the old code. Another process that reads them in that window sees the bug.
• The mod measures that the skill was delivered, not that the model read it.
• A collab step that runs out of time keeps running in the background until it ends; the mod no longer waits for it.
• The test engine cannot start a subagent, so the collab waits (hand-back, early answer, time limit, failed end) are tested in pipeline.ts with fake engine calls, and the whole run is checked live. Live on 2.1.284: a two-round hunt recorded FAIL then PASS, carried the fingerprint into round 2 and ended there; a collab kept the scanner's finding, read the critic's verdict, and its three hand-backs started no turn. A round in a git repository recorded PASS after the reverted run failed, the fix was back in place afterwards, and git stash list stayed empty.
• There is no bypass of a round's gates. /bughunt stop ends the hunt, and /bughunt off turns the mod off.

Development

make install     # eslint, typescript-eslint, typescript
make lint        # complexity limit 10, the build fails above it
make typecheck   # needs .claude/types/ from /plugin-types
make validate
make test        # claude plugin test