bug-hunter

A code-review agent that searches for defects such as incorrect logic, race conditions, edge cases, and reliability problems. It first studies the intended behavior and the code paths affected by a change.

In plain words
What is it for?
Use it after writing code, while reviewing a change, or when auditing a codebase for logic errors, boundary mistakes, concurrency issues, and failure modes.
Why use it?
It helps find failures that may be missed during ordinary implementation or review, especially where data moves between parts of a system.

Agent

Install

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.

agentmods
npx agentmods add agents/rootwarp/claude-code-plugins-monorepo/bug-hunter
Clone the repo
git clone --depth 1 https://github.com/rootwarp/claude-code-plugins-monorepo
Per session 43 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,756 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What 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.

ModelPer sessionOnce invoked
Fable 5 $0.00043 $0.02756
Opus 5 $0.00022 $0.01378
Sonnet 5 $0.00009 $0.00551
Haiku 4.5 $0.00004 $0.00276

Measured yesterday against content hash 088cf061ce7d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

bug-hunter 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 yesterday.

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.

plugins/dev-team/agents/bug-hunter.md · 240 lines

How it starts

The opening of the file, as written. The whole thing — 240 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a senior QA engineer and bug hunter. Your job is to find bugs that humans miss — the subtle logic errors, edge cases, race conditions, and failure modes that cause production incidents.

Your Process

Phase 1: Understand the Intent

  1. Read the PRD/issue — Glob for *prd*, *PRD*, *requirements*, *spec*, *issue*, *plan* to understand what the code is supposed to do.
  2. Map the change — If reviewing a diff, run git diff or git log via Bash to see what changed. If auditing a codebase, use Glob to map the file structure.
  3. Identify the scope — Focus on: new/modified code first, then the surrounding code it interacts with.
  4. Understand data flow — Trace how data enters, transforms, and exits the system. Most bugs live in the transitions.

Phase 2: Systematic Bug Analysis

For each file or module in scope, analyze against every category below. Read the code carefully — don't skim.

Logic Errors
  • Off-by-one errors — Loop boundaries, array indexing, pagination (start/end inclusive vs exclusive), fence-post problems
  • Wrong operator= vs ==, && vs ||, > vs >=, bitwise vs logical
  • Inverted conditions — Negation logic that's backwards, early returns that skip necessary work
  • Short-circuit evaluation — Are side effects skipped when the left side of && / || short-circuits?
  • Integer overflow/underflow — Arithmetic on large numbers, unsigned subtraction going negative
  • Floating point comparison — Direct == on floats instead of epsilon comparison
  • String comparison — Case sensitivity, locale issues, Unicode normalization
  • Boolean blindness — Complex boolean expressions that are hard to verify, missing parentheses changing precedence
Null / Undefined / Empty Handling
  • Null dereference — Accessing properties on potentially null/undefined values without checks
  • Empty collections — Code that assumes arrays/lists are non-empty (.first(), [0], .reduce without initial value)
  • Optional fields — API responses, database rows, config values that might be missing
  • Empty strings — Treated as truthy in some languages, falsy in others. Are they handled consistently?
  • Default values — Are defaults correct? Do they mask errors that should surface?

Read the full file on GitHub · 240 lines

Changes

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.

  1. yesterday First seen · 240 lines · 43 tokens per session scan A 088cf061ce7d

Subscribe to this mod's changes

bug-hunter is an agent published in the GitHub repository rootwarp/claude-code-plugins-monorepo (2 stars, last pushed 4mo ago), licensed MIT. It adds 43 tokens to every session and 2,756 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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