nitpicker

Multi-reviewer code review using LLMs. Spawns parallel agents with different models/prompts, aggregates their feedback into a final verdict. Supports two modes — parallel aggregation and actor-critic debate — across two task types: code review and free-form questions.

Each reviewer is an agentic loop that can call tools (read files, grep, glob, git commands) to explore the repo before writing its review. A separate aggregator model deduplicates and synthesizes the individual reviews into a final verdict.

Requirements

• Rust toolchain
• A git repository to review
• At least one configured LLM (API key or Gemini OAuth)

Installation

cargo install nitpicker

Quick start

export ANTHROPIC_API_KEY="your-api-key-here"

Review

nitpicker
nitpicker --repo /path/to/repo
nitpicker --repo /path/to/repo --prompt "focus on src/api/"
nitpicker --analyze src/components/
nitpicker --analyze  # entire repo

Parallel Mode

nitpicker --no-debate
nitpicker --no-debate --analyze src/
nitpicker --no-debate --max-turns 40

PR review

nitpicker pr
nitpicker pr https://github.com/owner/repo/pull/42
nitpicker pr --no-comment
nitpicker pr https://github.com/owner/repo/pull/42 --no-comment

Ask

nitpicker ask "should we use eyre or thiserror for error handling?"
nitpicker ask --no-debate "is this authentication flow secure?"
nitpicker ask --rounds 3 "should we split this module?"
nitpicker ask --max-turns 40 "should we split this module?"

Configuration

Configuration is loaded from (first match wins):

1. --config <path> (explicit flag)
2. nitpicker.toml in repo root
3. ~/.nitpicker/config.toml (global config)

# create a config in current directory
nitpicker init

# create a global config at ~/.nitpicker/config.toml
nitpicker init --global

Example nitpicker.toml:

[defaults]
debate = true          # optional, default: true
max_turns = 100        # optional, default: 100
log_trajectories = false # optional, default: false

[aggregator]
model = "claude-sonnet-4-6"
provider = "anthropic"
max_tokens = 8192        # optional, default: 8192

[[reviewer]]
name = "claude"          # used in output headers and logs
model = "claude-sonnet-4-6"
provider = "anthropic"

[[reviewer]]
name = "gpt"
model = "gpt-5.2-codex"
provider = "openai_compatible"
base_url = "https://api.openai.com/v1"
api_key_env = "OPENAI_API_KEY"

Tip: Use providers that were not used for the initial building of your codebase to enforce diversity of thought.

Unknown config keys are rejected. For example, use max_tokens for output length; token_limit is not a supported field.

Debate mode is enabled by default for nitpicker, nitpicker ask, and nitpicker pr. Pass --no-debate to use parallel aggregation for a single run. Use [defaults].max_turns or --max-turns to control the per-agent tool-use loop limit.

Set [defaults].log_trajectories = true to save per-agent JSONL traces and a final aggregation.json under ~/.nitpicker/sessions/session-<timestamp>-<pid>/.

Provider types

provider	Auth	Notes
anthropic	ANTHROPIC_API_KEY env var (or api_key_env)	base_url optional
gemini	GEMINI_API_KEY env var, or auth = "oauth"	—
openai	OPENAI_API_KEY env var (or api_key_env)	base_url optional
openrouter	OPENROUTER_API_KEY env var (or api_key_env)	explicit model names are recommended; model = "free" is experimental

anthropic_compatible and openai_compatible are accepted as aliases for backward compatibility.

OpenRouter models

openrouter supports both explicit pinned models and an experimental free auto-selection mode.

Pinned models are the supported default and the recommended setup:

# recommended: explicit model
[[reviewer]]
name = "qwen"
model = "qwen/qwen3-30b-a3b"
provider = "openrouter"

Experimental best-effort free auto-selection is also available:

# experimental: auto-select a currently available free model
# omit `model` or set model = "free"
[[reviewer]]
provider = "openrouter"

# explicit experimental form
[[reviewer]]
model = "free"
provider = "openrouter"

When model is omitted or set to "free", nitpicker tries to pick a currently working free model at startup.

This mode is convenient, but it is not production-stable and may fail due to upstream availability, routing differences, or timeouts.

If you want predictable behavior, pin explicit model names instead of relying on free auto-selection.

export OPENROUTER_API_KEY="your-key"

A free OpenRouter account is sufficient for the experimental free mode — no credit card required, just rate limits.

Gemini OAuth

Warning

Google has stated that using Gemini CLI OAuth with third-party software is a policy-violating use case and may trigger abuse detection or account restrictions. It is unclear how aggressively this is enforced, but you should assume there is real risk and use this at your own discretion. See: google-gemini/gemini-cli#22970

Gemini can be used via Google Code Assist OAuth (for free or with subscription, limits apply) — no API key needed, just a Google account. This approach mimics the auth of Gemini CLI, so no guarantees on reliability.

[aggregator]
model = "gemini-3-flash-preview"
provider = "gemini"
auth = "oauth"

[[reviewer]]
name = "gemini"
model = "gemini-3.1-pro-preview"
provider = "gemini"
auth = "oauth"

Authenticate once before reviewing:

nitpicker --gemini-oauth

This opens a browser, completes the OAuth flow, and saves the token to ~/.nitpicker/gemini-token.json. The token is refreshed automatically on subsequent runs.

CLI reference

nitpicker [OPTIONS]
nitpicker ask [--no-debate] [--rounds N] [--max-turns N] [OPTIONS] <topic>
nitpicker pr [URL] [--no-comment] [--no-debate] [--rounds N] [--max-turns N] [OPTIONS]
nitpicker init [--global]

Review (default)

--repo <PATH>      git repository to review [default: .]
--config <PATH>    config file [default: <repo>/nitpicker.toml, then ~/.nitpicker/config.toml]
--prompt <TEXT>    review instructions (optional, has a sensible default)
--analyze [PATH]   analyze existing code instead of reviewing changes
--no-debate        use parallel aggregation instead of actor-critic debate
--rounds <N>       maximum debate rounds [default: 5]
--max-turns <N>    maximum tool-use turns per agent or debate turn [default: 100 via config]
--gemini-oauth     run Gemini OAuth authentication flow and exit
-v, --verbose      show info-level logs (hidden by default)

PR subcommand

nitpicker pr [URL] [--no-comment] [--no-debate] [--rounds N] [--max-turns N] [--prompt TEXT] [--repo .] [--config PATH] [-v]

Reviews a GitHub PR using its title, description, and diff. Requires the gh CLI (gh auth login to authenticate).

• Without URL: reviews the current branch's open PR (must be run inside the repo)
• With URL (https://github.com/owner/repo/pull/N): clones the repo into a temp dir, checks out the PR branch, reviews it, then cleans up
• By default, posts the review as a PR comment. Pass --no-comment to skip posting.
• --no-debate, --rounds, and --max-turns work the same as in the default review mode

Ask subcommand

nitpicker ask [--no-debate] [--rounds N] [--max-turns N] [--repo .] [--config PATH] [-v] <topic>

Runs agents on a free-form question instead of a code diff. By default, two agents take turns as Actor/Critic before a meta-reviewer concludes. Pass --no-debate to switch to the parallel reviewer plus aggregator flow.

Debate mode (default)

Two LLM agents take turns exploring the codebase with file/git tools and submitting verdicts. The Critic can signal agreement (agree=true) to end early. A meta-reviewer synthesizes the dialogue.

• reviewer[0] in config → Actor (review: Reviewer)
• reviewer[1] in config → Critic (review: Validator)
• aggregator → Meta-reviewer

By default, nitpicker prints only the final synthesized result. Use --verbose to show intermediate debate output and the saved transcript path.

Transcript saved to {tempdir}/debate-{timestamp}.md or review-debate-{timestamp}.md.

Changelog

unreleased yet

• Graceful shutdown once turns are exhausted

0.2.3 — 2026-05-01

• Better nitpicker init experience and minor bug fixes

0.2.2 — 2026-04-30

• Session artifacts now capture tool trajectories and final aggregation output for debugging
• Default CLI output now stays focused on the final synthesized review unless --verbose is enabled

0.2.1 — 2026-04-30

• First class support for OpenRouter: new provider type, and experimental free auto-selection mode
• Minor bug fixes (breaking the cycle, temperature params)

0.2.0 — 2026-04-28

• PR comments are now included in the review prompt for full context
• Per-repo file lock prevents concurrent nitpicker pr runs on the same repository
• Atomic lock acquisition with stale lock detection (no TOCTOU race)

0.1.4 — 2026-04-23

• Proactive conversation compaction to prevent context overflow mid-review
• Claude Opus 4.7 compatibility fix
• Base branch detection fix for repos with master as default

0.1.3 — 2026-04-22

• Bounded subagent runtime for debate and review
• Configurable turn limits (--max-turns, [defaults].max_turns)
• Kimi repeating tool-call fix

0.1.2 — 2026-03-15

• pr subcommand: review GitHub PRs and post result as comment
• Debate synthesis posted as PR comment
• Three-dot diff for accurate stale-branch diffs
• Global config (nitpicker init --global)
• Rate limit handling with backoff