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.

Free Web version is available for open source projects.

Each reviewer is an agentic loop that can call tools (read files, grep, glob, git commands) to explore the repo before writing its review. Review prompts now encourage a quick initial map, a short working plan, and early subagent delegation for disjoint investigations. Tool outputs include lightweight headers and clearer truncation/no-match messages so agents can reason about partial evidence more reliably. 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
# force a fresh temp clone even when the URL points to your current repo
nitpicker pr https://github.com/owner/repo/pull/42 --clone
# machine-readable output for embedding (one JSON object on stdout)
nitpicker pr https://github.com/owner/repo/pull/42 --no-comment --json

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):

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

# create a config in current directory
nitpicker init

# prefer OpenRouter experimental free models when OPENROUTER_API_KEY is set
nitpicker init --free

# 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-5"
provider = "anthropic"
max_tokens = 16384       # optional, default: 16384

[[reviewer]]
name = "claude"          # used in output headers and logs
model = "claude-sonnet-5"
provider = "anthropic"
# max_tokens = 32768     # optional, default: unset (the provider's own per-model limit)

[[reviewer]]
name = "gpt"
model = "gpt-5.6-sol"
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.

max_tokens caps a single response, and on a reasoning model it is a budget for reasoning plus the answer — set too low, the model spends it all thinking and returns empty content, which is indistinguishable from a model that said nothing. Reviewers therefore default to no cap (the provider applies its own per-model limit); set one only to bound spend. The aggregator writes one bounded synthesis and defaults to 16384. Two exceptions: Anthropic's API requires the field, so an unset reviewer cap becomes 8192 there — raise it explicitly if your model reasons past that; and auth = "codex" ignores the setting entirely, since that endpoint rejects max_output_tokens.

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`), or `auth = "azure-ad"`	`base_url` optional
`gemini`	`GEMINI_API_KEY`/`GOOGLE_AI_API_KEY` env var (or `api_key_env`), or `auth = "agy-keyring"`	`base_url` optional (e.g. a local Gemini-compatible server); `agy-keyring` reuses the Antigravity CLI OAuth token from the system keyring — research only, see warning
`openai`	`OPENAI_API_KEY` env var (or `api_key_env`), `auth = "azure-ad"`, or `auth = "codex"`	`codex` reuses your ChatGPT subscription via the Codex CLI token — research only, see warning
`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.

auth = "azure-ad" authenticates with a refreshing Azure AD (Entra ID) token instead of a static key — for OpenAI and Anthropic models hosted on Azure AI Foundry. Requires a build with the azure feature, see below.

auth = "codex" authenticates with your ChatGPT Plus/Pro (Codex) subscription instead of a paid API key, reusing the token the Codex CLI stores on disk, see below.

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.

Antigravity Keyring (research only)

Caution

Research only — do not use on a Google account you care about. AG2's Additional Terms of Service Section 6 prohibits "using the Service in connection with products not provided by us", which directly covers reusing the agy OAuth token from a third-party client like nitpicker. Google has been actively enforcing this in 2026: paid AI Ultra subscribers have received account suspensions, often without warning, for using third-party AG2 OAuth bridges (OpenClaw, OpenCode, Pi Agent). Detection appears aggressive — even light testing has triggered bans. The earlier gemini-cli OAuth path was discouraged on similar grounds (discussion). If you want billed Gemini access without this risk, set GEMINI_API_KEY and drop the auth line.

AG2 is Google's current agentic IDE, succeeding both the older Gemini CLI OAuth path and the earlier AG1 preview. The gemini-3.x family ships only through AG2's CloudCode backend, so auth = "agy-keyring" exists purely as a research path to compare those models against the rest of the reviewer pool, with full awareness of the ToS posture above.

The proxy reads agy's OAuth token from the system keyring (service=gemini, account=antigravity) via the keyring crate (Secret Service on Linux, Keychain on macOS, Credential Manager on Windows), relies on agy to refresh it, and routes chat through CloudCode's v1internal:streamGenerateContent SSE endpoint. Run agy and complete its login first. NITPICKER_ANTIGRAVITY_PLATFORM can override the auto-detected platform enum if needed.

This path requires a build with the antigravity feature (off by default, since it pulls in the local proxy stack — axum — and the keyring crate with its native backends):

cargo build --release --features antigravity
# or: cargo install --features antigravity ...

Without the feature, auth = "agy-keyring" is rejected at config validation with a build hint, and nitpicker init won't offer the keyring reviewer.

Tested AG2 models (current author config): gemini-3.1-pro-low, gemini-3.5-flash-low. Other IDs returned by fetchAvailableModels (e.g. gemini-3-flash-agent) likely work but have not been exercised.

[aggregator]
model = "gemini-3.5-flash-low"
provider = "gemini"
auth = "agy-keyring"

[[reviewer]]
name = "gemini"
model = "gemini-3.1-pro-low"
provider = "gemini"
auth = "agy-keyring"

ChatGPT/Codex subscription (research only)

Caution

Research only. This reuses the OpenAI Codex CLI's public OAuth client to call OpenAI through your ChatGPT Plus/Pro subscription. Third-party use of that client is arguably outside OpenAI's terms — same posture as the Antigravity path above. Use a paid OPENAI_API_KEY for anything you care about.

auth = "codex" (on an openai reviewer/aggregator) reuses the OAuth token the Codex CLI stores in ~/.codex/auth.json. Log in once with codex login (choosing your ChatGPT account, not an API key); nitpicker reads the token read-only and refreshes the short-lived access token in-memory via the refresh token — it never writes back to auth.json. Set CODEX_HOME to override the token directory.

Under the hood this talks to the Codex subscription endpoint (chatgpt.com/backend-api/codex/responses), which speaks the OpenAI Responses API with subscription-specific quirks (a required top-level system prompt, mandatory streaming, store: false, no max_output_tokens, and encrypted reasoning items round-tripped across turns since nothing is server-side persisted); nitpicker handles all of that transparently. No API-key env var is needed.

Models are your subscription's Codex models (e.g. gpt-5.6-sol, gpt-5.6-terra, gpt-5.6-luna):

[aggregator]
model = "gpt-5.4"
provider = "openai"
auth = "codex"

[[reviewer]]
name = "codex"
model = "gpt-5.4"
provider = "openai"
auth = "codex"

Azure AD (Azure AI Foundry)

Call OpenAI and Anthropic models hosted on Azure AI Foundry using a short-lived Azure AD (Entra ID) token instead of a static key. nitpicker acquires the token via the Azure SDK and transparently refreshes it (rebuilding the client before the token expires), so long reviews and debates don't die mid-run — the equivalent of the Python SDK's azure_ad_token_provider.

This path requires a build with the azure feature (off by default, since it pulls in the Azure SDK and needs Rust 1.88+):

cargo build --release --features azure
# or: cargo install --features azure ...

Set auth = "azure-ad" on an openai or anthropic reviewer/aggregator and point base_url at your Foundry endpoint:

[[reviewer]]
name = "gpt"
provider = "openai"                                                  # OpenAI models → /openai/v1
base_url = "https://<resource>.services.ai.azure.com/openai/v1"
model = "gpt-4o"                                                     # your Foundry deployment / model
auth = "azure-ad"

[[reviewer]]
name = "claude"
provider = "anthropic"                                               # Anthropic models → /anthropic
base_url = "https://<resource>.services.ai.azure.com/anthropic"
model = "claude-sonnet-4-5"
auth = "azure-ad"
azure_credentials = "dev"                                            # optional, see below

Optional per-reviewer/aggregator fields:

azure_scope — AAD token scope. Defaults to https://cognitiveservices.azure.com/.default.
azure_credentials — selects the credential chain, mirroring the Azure SDK's AZURE_TOKEN_CREDENTIALS:
- "dev" — developer tools only (az login, Azure Developer CLI), excluding managed identity. Use on a VM where you want az login instead of a system-assigned managed identity.
- "prod" — env service principal (AZURE_TENANT_ID/AZURE_CLIENT_ID/AZURE_CLIENT_SECRET), then managed identity.
- unset / "auto" — env service principal → managed identity → developer tools, in that order.
If unset, the AZURE_TOKEN_CREDENTIALS env var is honored as a fallback.

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] [--free] [--repo <DIR>]

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)
--context-file <PATH>  inject a file's contents into the prompt; repeatable
--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]
-v, --verbose          show info-level logs (hidden by default)

`--context-file`

The agents' own tools are sandboxed to the repository, so they cannot open a design doc that lives outside it. --context-file reads such a file directly into the prompt:

nitpicker --context-file ~/notes/migration-plan.md --context-file /tmp/rfc.md

Available on the default review mode, ask, and pr; the flag may be given before or after the subcommand. Files are injected verbatim, in the order given, after the task and any --prompt text. Total injected size — contents plus each block's wrapper — is capped at 256 KiB; a missing, non-regular (FIFO, device node), binary, or non-UTF-8 file is an error, raised before any model is called. Because the contents are placed in the task prompt rather than the system prompt, spawned subagents do not inherit them.

PR subcommand

nitpicker pr [URL] [--no-comment] [--no-debate] [--rounds N] [--max-turns N] [--prompt TEXT] [--context-file PATH] [--repo .] [--config PATH] [--json] [-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
--json emits a single machine-readable JSON object on stdout (status, PR metadata, models, report_markdown, usage, …) instead of the human report, with all logs/progress on stderr — handy for calling nitpicker as a subprocess. Exits non-zero on failure, with a status: "error" object on stdout. The usage block reports aggregate input_tokens/output_tokens/total_tokens, cached_input_tokens/cache_creation_input_tokens, and subagents_spawned for the run (best-effort: successful completions only). The cache fields are a breakdown of input_tokens, not an extra charge — a healthy multi-turn run shows most of its input served from cache. Cost formulas must discount them: input_tokens now counts cache reads on every provider (before 0.8.3 the Anthropic path omitted them), so a naive input_tokens * input_price over-states a cache-heavy run.

Ask subcommand

nitpicker ask [--no-debate] [--rounds N] [--max-turns N] [--context-file PATH] [--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

Interactive text runs show a compact cast/progress view while debating, then print the final synthesized result. In a terminal, --verbose also shows intermediate debate output and the saved transcript path; redirected stdout stays final-report-only.

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

Exit codes (default review and `ask`)

code	meaning
0	clean verdict
1	hard failure — no verdict (bad config, missing key, every reviewer/turn failed)
2	CLI usage error (clap's exit code for bad arguments)
3	degraded verdict — report printed, but a reviewer failed, or a debate turn failed or ended without calling `submit_verdict`

Non-interactive, non-verbose stdout carries exactly the final report, so the binary can be driven as a subprocess: read stdout for the verdict, branch on the exit code. pr keeps its own contract (--json emits status: ok|error and exits 0/1).

Using the agent as a library

The agentic core — the loop, the file/git tools, and the provider-agnostic LLM clients — lives in a separate crate, nitpicker-agent, with none of the CLI/review/PR machinery. Use it to drive your own file-reading agent with subagents:

use nitpicker_agent::prelude::*;
use std::path::Path;

let client = client_from_env(LLMProvider::Anthropic { base_url: None, api_key_env: None })?;
let result = AgentBuilder::new("explorer", "claude-sonnet-5", "You explore codebases.", client)
    .subagent_system_prompt("You are a focused file-reading worker. Report findings concisely.")
    .run("Map the module layout of this repo.", &file_agent_tools(), Path::new("."))
    .await?;
println!("{}", result.text);

file_agent_tools() is the read-only file/git toolset plus spawn_subagent. You control the top-level prompt, the subagent prompt, the toolset, and the client; config-file-driven client construction is available via the config/provider modules. See crates/nitpicker-agent/examples/file_agent.rs.

Changelog

0.8.5 — 2026-08-05 (nitpicker-agent 0.2.1)

Session recorder fixes: unique per-agent record identities (no more shared root/subagent-N), failed subagent spawns logged, 1-based compact turn numbers, flushed appends.
reflect no longer renders successful spawns or blocked cycles as failures.

0.8.4 — 2026-08-05

New --context-file <PATH> flag (repeatable) injects out-of-repo files (regular files only, capped at 256 KiB in total including block wrappers) into the task prompt for review, ask, and pr; accepted before or after the subcommand.
--repo, --config, and -v/--verbose are now global flags: accepted before or after a subcommand, no longer silently ignored in the root position. init honors --repo as the directory to write nitpicker.toml into, and rejects --config.

0.8.3 — 2026-08-05 (nitpicker-agent 0.2.0)

Stable Tool Definitions: Send tool definitions in name-sorted order to preserve request prefix determinism and maximize provider prompt-cache hits across turns.
Cache-Aware Token Metering: Added cached_input_tokens and cache_creation_input_tokens to TokenUsage and pr --json, normalized input_tokens across provider cache shapes (fixing compaction triggers on auto-caching providers), and updated progress display (e.g. 1.0M in · 90% cached).
Flexible Output Caps: Removed hardcoded 8192-token output caps on agent turns and compaction (preventing reasoning models from exhausting token budgets on internal thinking before emitting output). Added max_tokens configuration per reviewer (None uses provider default; aggregator defaults to 16,384).
Improved Empty Response Diagnostics: Surfaced finish_reason and token usage when retrying empty responses.
Unterminated Think Block Salvage: Improved parsing to recover verdicts buried after unclosed <think> tags even when preceding content is present.
Resilient Compaction: Made history compaction best-effort so a summarizer failure no longer aborts the review run.
Alloy Slot Cap Isolation: Scoped max_tokens per model in AlloyClient pools.
Dependency & Cleanup: Bumped rig-core to 0.41 and removed redundant fc_ tool call ID normalization.
Breaking (nitpicker-agent): Replaced AgentResult token fields with usage: TokenUsage. AlloyClient::new now takes Vec<AlloySlot>.

0.8.2 — 2026-07-14 (nitpicker-agent 0.1.2)

Prevent debate subagents from inheriting submit_verdict tools to avoid premature convergence.
Run history compaction under a dedicated summarizer system prompt.
Wrap project context (CLAUDE.md/AGENTS.md) in <context-only> tags and pass task to parallel aggregator.
Added ReviewScope (Diff/Static) and --analyze static-analysis mode.

0.8.1 — 2026-07-03

Bumped rig-core to 0.39; simplified Codex assistant text normalization.

0.8.0 — 2026-06-16

Extracted core agent logic into published nitpicker-agent crate.
Added subagent_system_prompt customization to AgentConfig.

0.7.1 — 2026-06-14

Exit 3 for degraded review/ask verdicts; refined interactive progress rendering.
Audit fixes: hardened git tool sandboxing, provider auth/retry error classification, and pr checkout safety.

0.7.0 — 2026-06-07

Added research auth = "codex" for OpenAI provider using local Codex CLI OAuth tokens.
Fixed Codex multi-turn reasoning and gated keyring auth under antigravity feature flag.

0.6.3 — 2026-06-06

Security audit fixes: restricted git subcommands (for-each-ref/show-ref), panic-safe detached HEAD restore, retry classifier matching.

0.6.2 — 2026-06-05

nitpicker pr --json emits machine-readable output on stdout with logs/spinners on stderr.
Fixed macOS symlink workspace canonicalization under pr --clone.

0.6.1 — 2026-06-05

Concurrent subagent execution: run spawn_subagent calls in parallel via join_all bounded by a global semaphore (default 16).

0.6.0 — 2026-06-02

Added auth = "azure-ad" support for OpenAI/Anthropic providers via Entra ID bearer tokens (gated under azure feature flag).

0.5.1 — 2026-05-25

PR checkout safety improvements, --clone flag, partial clones (--filter=blob:none).

0.5.0 — 2026-05-24

Added auth = "agy-keyring" for Gemini; removed legacy auth = "oauth".

0.4.0 — 2026-05-17

Added Alloy mode (--alloy) to pool reviewer models into a shared random-selection pool.

0.3.0 – 0.3.3 — 2026-05-06 – 2026-05-11

OpenRouter free model auto-selection (init --free), trajectory logging, reflect analysis tool.

0.1.2 – 0.2.3 — 2026-03-15 – 2026-05-01

PR review subcommand, debate mode synthesis, proactive conversation compaction, bounded subagent runtime, atomic file locks.

Name		Name	Last commit message	Last commit date
Latest commit History 114 Commits
crates/nitpicker-agent		crates/nitpicker-agent
src		src
.gitignore		.gitignore
CLAUDE.md		CLAUDE.md
Cargo.lock		Cargo.lock
Cargo.toml		Cargo.toml
LICENSE		LICENSE
README.md		README.md
nitpicker.toml.example		nitpicker.toml.example
rustfmt.toml		rustfmt.toml

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nitpicker

Requirements

Installation

Quick start

Review

Parallel Mode

PR review

Ask

Configuration

Provider types

OpenRouter models

Antigravity Keyring (research only)

ChatGPT/Codex subscription (research only)

Azure AD (Azure AI Foundry)

CLI reference

Review (default)

`--context-file`

PR subcommand

Ask subcommand

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Exit codes (default review and `ask`)

Using the agent as a library

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nitpicker

Requirements

Installation

Quick start

Review

Parallel Mode

PR review

Ask

Configuration

Provider types

OpenRouter models

Antigravity Keyring (research only)

ChatGPT/Codex subscription (research only)

Azure AD (Azure AI Foundry)

CLI reference

Review (default)

--context-file

PR subcommand

Ask subcommand

Debate mode (default)

Exit codes (default review and ask)

Using the agent as a library

Changelog

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`--context-file`

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