Review Sheep

Review Sheep is a Python library for reading GitHub pull requests through two separate capabilities:

• Inquiry answers lightweight questions from pull-request metadata.
• Review asks whole-pull-request Lens agents to inspect either a GitHub API Manifest (interactive Chat) or a complete fixed-SHA Git checkout (CI), then returns structured Pydantic Findings.

The Review Sheep Python library is read-only. It never submits reviews, changes labels, or otherwise writes Findings back to GitHub. Publishing a rendered Report is the caller's responsibility; the bundled CI workflow is one such caller and publishes the Report as a pull-request conversation comment.

The implementation uses LangChain agents for model and tool execution, and LangGraph for conversational state orchestration. See ARCHITECTURE.md for the complete design.

Install

Review Sheep requires Python 3.11 or newer.

pip install review-sheep

For an OpenAI-backed model, install the genuinely optional provider extra:

pip install "review-sheep[openai]"

anthropic_model and Langfuse tracing have their own extras too:

pip install "review-sheep[anthropic]"
pip install "review-sheep[tracing]"

langchain-anthropic is also pulled in transitively today by the deepagents dependency, so anthropic_model works even without the anthropic extra; declaring it keeps Review Sheep's own dependency contract accurate independent of what deepagents requires.

To install from source instead:

pip install .

Test coverage

Run the full test suite with per-module and total statement coverage using the development dependency set. Store the coverage data outside the source tree and enforce the same 97% floor used by CI:

COVERAGE_FILE="${TMPDIR:-/tmp}/review-sheep.coverage" \
uv run --extra dev --extra openai pytest \
  --cov=src/review_sheep \
  --cov-report=term-missing \
  --cov-fail-under=97

The command exits non-zero when tests fail or total source statement coverage falls below 97%; it does not require a manual coverage-tool installation. Coverage is reported for the review_sheep source package. CI writes the coverage data to the runner's temporary directory, so coverage artifacts do not leave generated files in the source tree.

Inquiry

The caller constructs the model and GitHub client explicitly. Inquiry exposes metadata-only tools; it does not fetch changed code or run Review subagents.

from github import Auth, Github
from langchain_openai import ChatOpenAI

from review_sheep import GitHubPullRequestReader, create_inquiry_agent

github = GitHubPullRequestReader(
    client=Github(auth=Auth.Token("github-token")),
    default_repo="acme/widgets",
)
model = ChatOpenAI(model="gpt-5-mini", api_key="openai-key")

inquiry_agent = create_inquiry_agent(model=model, github=github)
answer = inquiry_agent.ask("Which pull requests are awaiting review?")
if answer.error:
    print(answer.error)
else:
    print(answer.text)

Simple Chatbot Graph

Build a continuous LangGraph chatbot that classifies each turn and routes it to the LangChain Inquiry agent, changed-code Review agent, or an unrelated-message scope response:

START -> IntentClassifier -> Bot | ReviewBot | UnrelatedBot -> END

from langchain_core.messages import HumanMessage

from review_sheep import (
    ChatState,
    create_chatbot_graph,
    create_intent_classifier,
    create_manifest_review_agent,
)

chatbot = create_chatbot_graph(
    agent=inquiry_agent,
    classifier=create_intent_classifier(model=model),
    reviewer=create_manifest_review_agent(source=github, model=model),
)
state = ChatState(messages=[])
state = chatbot.invoke(state)
print(state["messages"][-1].content)

# Continue by appending each user reply to the returned state.
state["messages"] = [
    *state["messages"],
    HumanMessage(content="Which open PRs in acme/widgets need review?"),
]
state = chatbot.invoke(state)

IntentClassifier returns a Pydantic routing decision. Bot keeps the structured InquiryAnswer in state["answer"]; ReviewBot keeps the structured Review or ReviewError in state["review"]. UnrelatedBot does not invoke either agent and returns only the chatbot's supported scope.

Review and Report

For CI and library callers with a complete checkout, Review runs a LangGraph workflow that verifies one clean local checkout against GitHub's PR base/head SHAs. Correctness, security, and conventions-and-tests agents share that fixed checkout and run concurrently. They generate diffs from git diff base...head and read complete source files directly. Findings retain their Location, Severity, Confidence, and originating Lens; results are merged in stable Lens order and overlapping Findings are not merged.

from review_sheep import (
    GitCheckoutSource,
    Review,
    create_deep_review_agent,
    render_report,
)

checkout = GitCheckoutSource(revisions=github, root="/work/pr-42")
reviewer = create_deep_review_agent(source=checkout, model=model)
result = reviewer.review(repo="acme/widgets", number=42)

if isinstance(result, Review):
    report = render_report(result)
    print(report.text)
else:
    print(
        f"{result.operation.value} failed for "
        f"{result.repo}#{result.pull_request_number}: {result.message}"
    )

The lower-level create_review_agent(source=..., runner=...) seam accepts deterministic collaborators for tests or a caller-owned Review implementation.

For repeated Reviews of the same repository, use CachedGitCheckoutSource to keep one credential-free bare mirror while creating a fresh disposable worktree for every PR revision. Git authentication remains delegated to Git's normal credential helper or environment; do not put tokens in remote_url.

from review_sheep import CachedGitCheckoutSource, create_deep_review_agent

checkout = CachedGitCheckoutSource(
    revisions=github,
    cache_root="~/.cache/review-sheep/repos",
)
reviewer = create_deep_review_agent(source=checkout, model=model)
result = reviewer.review(repo="acme/widgets", number=42)

The Review graph removes the disposable worktree after both successful and failed Reviews; the bare mirror remains available for the next Review. Mirror mutation is coordinated by a lock per repository, so different repositories can proceed independently. lock_timeout defaults to 30 seconds; contention beyond that raises RepositoryMirrorLockTimeout and becomes a structured prepare_checkout ReviewError when used through the Review graph. Call cleanup_stale() periodically to remove worktrees unused for 24 hours and mirrors unused for 30 days. It returns counts for removed resources, active resources skipped, and actionable cleanup errors; active worktrees hold leases and are never removed by that pass. Failed initialization or fetches are retried through a safe mirror rebuild.

Runtime cache configuration

The CI entrypoint exposes the cache without requiring application code changes. The cache is disabled by default, preserving the fixed-checkout behavior. Set these environment variables or use the equivalent scripts/review_pr.py options:

For example, a local run can use a private cache and opt into cleanup:

mkdir -m 700 -p "$HOME/.cache/review-sheep/repos"
REVIEW_CACHE_ROOT="$HOME/.cache/review-sheep/repos" \
REVIEW_CACHE_CLEANUP=true \
uv run python scripts/review_pr.py --repo acme/widgets --pr-number 42 \
  --checkout "$PWD/review-target"

The CLI also accepts --cache-root, --cache-lock-timeout, --cache-worktree-retention, --cache-mirror-retention, and --cache-cleanup; --no-cache explicitly bypasses a cache configured in the environment. Cache directories should be dedicated to Review Sheep, owned by the review process, and permissioned 0700. Do not put tokens in the cache path or repository URL; configure Git's credential helper or the CI credential environment instead. Concurrent Reviews of one repository serialize mirror operations while different repositories remain independent.

Cache logs report hits, misses, fetches, lock contention, worktree creation, cleanup, and recovery using repository identifiers, cache paths, and counts only. They do not log credentials, remote URLs, diffs, or complete repository contents. To verify the behavior locally, run uv run pytest tests/test_config.py tests/test_checkout.py tests/test_entrypoints.py; to disable it, unset REVIEW_CACHE_ROOT or pass --no-cache.

create_deep_review_agent also accepts an ordered collection of custom Lenses. They run concurrently with the built-in Lenses over the same fixed checkout and return standard Findings tagged with their custom identifiers. For example, add an API-compatibility Lens to a fixed-checkout Review like this:

from review_sheep import CustomLens, Review, create_deep_review_agent

custom_lens = CustomLens(
    identifier="api-compatibility",
    instructions=(
        "Review public API changes for backwards-incompatible behavior. "
        "Report only actionable compatibility regressions."
    ),
)
reviewer = create_deep_review_agent(
    source=checkout,
    model=model,
    lens_concurrency=2,
    custom_lenses=[custom_lens],
)
result = reviewer.review(repo="acme/widgets", number=42)
if isinstance(result, Review):
    for finding in result.findings:
        print(f"[{finding.lens}] {finding.description}")

Define a custom Lens

Review extensions can describe a caller-owned review perspective with the public CustomLens contract. Each custom Lens has a stable lower-case, kebab-case identifier and non-blank instructions. Identifiers cannot reuse the built-in correctness, security, or conventions-and-tests names, and validate_custom_lenses rejects duplicate identifiers while preserving caller order. Findings can carry either a built-in Lens value or a custom identifier; built-in Finding serialization remains unchanged. The instructions value is the custom Lens's caller-owned, concern-specific review guidance; it does not change the built-in Lens definitions or the Review's shared snapshot contract.

Pass the ordered definitions to create_manifest_review_agent or review_pull_request_tool to run them alongside the built-in Lenses. All Lenses receive the same Manifest snapshot, virtual diff files, and caller-owned tools; Findings are returned in built-in order followed by custom declaration order:

custom_lenses = [
    CustomLens(
        identifier="api-compatibility",
        instructions="Review public API changes for compatibility regressions.",
    )
]
reviewer = create_manifest_review_agent(
    source=source,
    model=model,
    lens_concurrency=2,
    custom_lenses=custom_lenses,
)

Add caller-provided Review tools

Both Review constructors accept optional LangChain tools. Review Sheep gives each Lens the built-in repository or Manifest tools plus the caller-provided tools, so a Review can use read-only context such as database schema or table metadata:

from langchain_core.tools import tool

@tool
def fetch_db_metadata(table: str) -> str:
    """Fetch read-only metadata for one database table."""
    return metadata_client.describe_table(table)

reviewer = create_deep_review_agent(
    source=checkout,
    model=model,
    tools=[fetch_db_metadata],
)

create_manifest_review_agent and review_pull_request_tool accept the same tools argument. Tools are owned and authorized by the caller; Review Sheep does not manage their credentials or enforce that external operations are read-only. Prefer narrowly scoped access, bounded results, and thread-safe implementations because all Lenses run concurrently. Tool results are sent to the model and can provide evidence for Findings. Custom Lens definitions do not carry credentials themselves; inject credentials only through caller-owned tools with the authorization and secret-handling policy appropriate for your application.

Add caller-provided Review Context

A Review Context gives every Lens background the pull request itself does not contain, such as a linked Jira ticket or Notion spec. Unlike a tool, it runs once per Review, before any Lens starts, and its text is shared by every Lens. Review Sheep owns no Jira or Notion client: you supply the function that fetches the text, along with its credentials and authorization.

from review_sheep import (
    PullRequestContext,
    ReviewContext,
    create_deep_review_agent,
    jira_issue_context,
    notion_page_context,
)

def fetch_jira_issue(key: str) -> str:
    issue = jira_client.issue(key)
    return f"{issue.fields.summary}\n\n{issue.fields.description or ''}"

def fetch_notion_page(page_id: str) -> str:
    return my_notion_page_to_text(notion_client, page_id)

def fetch_release_notes(pull_request: PullRequestContext) -> str:
    return release_notes_for(pull_request.repo, pull_request.head_ref)

reviewer = create_deep_review_agent(
    source=checkout,
    model=model,
    context_providers=[
        jira_issue_context(fetch_jira_issue, project_keys=["STRAITSX"]),
        notion_page_context(fetch_notion_page),
        ReviewContext(identifier="release-notes", fetch=fetch_release_notes),
    ],
)

• ReviewContext(identifier=..., fetch=...) is the base contract. fetch receives a PullRequestContext (repo, number, base/head SHA, title, body, and head branch) and returns text. Identifiers use the same kebab-case rule as custom Lenses and must be unique.
• linked_reference_context finds every match of pattern in the PR title, body, and head branch, then calls fetch once per unique reference, up to max_references (default 5). A pattern with a capturing group passes the first group.
• jira_issue_context matches Jira Cloud links such as https://acme.atlassian.net/browse/STRAITSX-30185 (and selectedIssue= board links). Bare keys such as STRAITSX-30185 or a branch named straitsx-30185-fix match only for the listed project_keys, so text like UTF-8 is never treated as a ticket. fetch_issue receives the upper-case key. For self-hosted Jira, use linked_reference_context with your own pattern.
• notion_page_context does the same for notion.so and notion.site links and passes fetch_page a lower-case 32-character page ID.
• Neither helper calls the Jira or Notion API; your fetch function does.

create_manifest_review_agent accepts the same context_providers argument. Each Review Context result is truncated to 8,000 characters and wrapped in a <caller_context> block marked as untrusted, so Lenses use it as background about intent but ignore instructions inside it. A context that raises or returns blank text is logged and skipped; the Review still runs. The bundled CLI and GitHub Action do not take Python callables, so pass Review Context through your own entrypoint, for example a reviewer_factory that calls create_deep_review_agent(..., context_providers=[...]).

Custom Lens output is validated against the standard Finding fields and is returned unmerged after the built-in Findings, in the declaration order supplied to custom_lenses. The same identity appears in the Review, rendered Report, logs, and tracing metadata. If a Lens fails, the Review returns its existing ReviewError boundary with the failing Lens identity; successful partial results are exposed only where the surrounding public API already supports partial results.

Use Review as a LangChain tool

review_pull_request_tool wraps the Manifest Review workflow — fetching a GitHub API snapshot, running every Lens, and rendering the Report — behind one LangChain tool, so it can be dropped straight into another agent's own tools=[...] list instead of wiring GitHubPullRequestReader, create_manifest_review_agent, and render_report together by hand:

from review_sheep import GitHubPullRequestReader, review_pull_request_tool

source = GitHubPullRequestReader(client=github)
tool = review_pull_request_tool(model, source)

my_agent = create_agent(model=model, tools=[*my_tools, tool])

The tool takes repo and number arguments and returns the rendered Markdown Report as a string; a failed Review is returned as descriptive error text rather than raised, so the calling agent can reason about or relay it.

Try the intent-routed chatbot

Install the project with the provider extra you want to test. For OpenAI:

uv sync --extra openai --extra dev

Configuration and secret injection

The library entrypoints consume explicit configuration objects. Construct a ChatConfig or CIConfig and pass it to review_sheep.chat.main or review_sheep.ci.main when embedding Review Sheep in an application. These core paths do not read process environment values or files.

Set lens_concurrency on ChatConfig, CIConfig, create_deep_review_agent, or create_manifest_review_agent to limit how many Lens agents run at once. The default is one worker per configured Lens. The review_pull_request_tool helper accepts the same argument.

For example, an application can inject values from its own secret manager:

from review_sheep import ChatConfig
from review_sheep.chat import main

config = ChatConfig(
    github_token=get_secret("GITHUB_TOKEN"),
    model=get_setting("OPENAI_MODEL"),
    api_key=get_secret("OPENAI_API_KEY"),
)
main(config=config)

The bundled scripts are process-environment adapters. The interactive script reads GITHUB_TOKEN, OPENAI_MODEL, OPENAI_API_KEY, and optional BASE_URL and REVIEW_LOG_LEVEL from the environment of the process that launches it:

export GITHUB_TOKEN="<read-only-github-token>"
export OPENAI_MODEL="<model-id>"
export OPENAI_API_KEY="<provider-api-key>"
export REVIEW_LOG_LEVEL="INFO"
# Optional: export REVIEW_LENS_CONCURRENCY="4"
# Optional: export BASE_URL="<compatible-endpoint>/v1"
uv run python scripts/review_chat.py

The CI adapter uses the environment and command-line values documented in GitHub Actions PR Review. Its non-secret CLI arguments (--repo, --pr-number, --checkout, --instructions, --lens-concurrency, and --model-tier) take precedence over their environment defaults. Explicit configuration passed directly to a library entrypoint takes precedence over all adapter inputs because the core entrypoint does not consult the environment. Keep GitHub and model credentials in process environment values, CI secret variables, or a secrets manager; never pass secrets as CLI arguments, commit them to a checkout, or put them in example files.

Neither production entrypoint loads a local .env file. A local shell, CI secret adapter, or secrets manager must populate the process environment explicitly. The checked-in .env.example documents the non-secret Lens concurrency setting; copy or adapt it in the environment-loading mechanism owned by your application.

The following optional tracing variables are read from the process environment:

• Langfuse: LANGFUSE_PUBLIC_KEY, LANGFUSE_SECRET_KEY, optional LANGFUSE_BASE_URL, LANGFUSE_TRACING_ENVIRONMENT, and LANGFUSE_TRACING_ENABLED=false.
• MLflow: MLFLOW_TRACKING_URI and optional MLFLOW_EXPERIMENT_NAME.
• Review execution: optional REVIEW_LENS_CONCURRENCY limits the number of Lens agents running concurrently. It must be a positive integer.

Ask what Review Sheep can do, ask metadata questions, or request a changed-code Review naturally. The classifier selects the correct agent path; ReviewBot asks for a repository or pull-request number when the request omitted it. Type exit or quit to stop.

Review Sheep chatbot ready; type exit or quit to stop.
Bot: What would you like to know or review about pull requests?
You: Which pull requests are open in other/project?
Bot: Open pull requests: #123 ...
You: What is the review state of #123?
Bot: Pull request #123 ...
You: Review changed code in other/project#123 for correctness
Bot: # Review Report: other/project#123
You: quit

The GitHub token must be able to read the target repository; private repositories require corresponding read access. For changed-code Review, Chat fetches the PR files from GitHub, verifies that the head SHA stayed stable, and creates an in-memory /manifest.json plus /diffs/<path>.diff files. It does not clone the target repository and does not require REVIEW_CHECKOUT.

Progress logs go to stderr. INFO shows intent routing, GitHub snapshot, Manifest construction, each Lens, Finding counts, and Report rendering. Set REVIEW_LOG_LEVEL=DEBUG to also print Manifest paths, patch sizes, tool results, and structured Findings. Credentials and complete source/diff contents are not logged. Both Chat routes remain read-only and never post reviews, comments, or Findings to GitHub.

Optional multi-backend tracing

Tracing is opt-in and each backend is configured independently:

• Langfuse activates when LANGFUSE_PUBLIC_KEY and LANGFUSE_SECRET_KEY are both present. LANGFUSE_BASE_URL and LANGFUSE_TRACING_ENVIRONMENT are optional; LANGFUSE_TRACING_ENABLED=false disables it explicitly.
• MLflow activates when MLFLOW_TRACKING_URI is present. The optional MLFLOW_EXPERIMENT_NAME defaults to review-sheep.
• Set both groups to send the same Chat Review turn to both backends. A backend initialization failure is logged and does not disable the other backend.

Each Chat user turn is a review-sheep-chat-turn trace. The outer Chat LangGraph callback propagates into intent classification, Inquiry, Manifest Review, and all Lens agents. The CLI flushes configured backends before exit; flush failures are logged without replacing the Chat result. See the Langfuse LangGraph integration.

The CI entrypoint uses the same environment variables. Its root trace is named review-sheep-ci-review and uses the stable correlation session ci:<repo>#<number>, including for parallel checkout Lenses. For the reusable GitHub Actions workflow, pass the optional tracing values through the LANGFUSE_* and MLFLOW_* workflow-call secrets shown below.

Tracing callbacks can observe prompts, model responses, LangGraph state, tool names, tool arguments/results, repository and pull-request metadata, and the source or diff content included in model/tool activity. Manifest Review sends virtual manifest/diff data; CI Review can send file and diff content read from the fixed checkout. Review Sheep does not redact repository content before the callback receives it, so do not enable tracing for repositories or prompts that the configured backend must not store.

The same callback events are offered to both adapters, but each backend serializes them using its own schema: Langfuse receives LangChain/LangGraph observations with the configured session, tags, run names, prompts, outputs, and tool observations; MLflow receives corresponding LangChain spans under the configured tracking URI and experiment. Model metadata such as provider/model names and invocation metadata may also be included by the LangChain tracer. The exact fields depend on the installed backend SDK version, so treat both destinations as capable of receiving the full categories above rather than assuming that a prompt or diff is private merely because it is not in a top-level Review result.

Treat the Langfuse project and MLflow tracking server/experiment as sensitive data destinations: restrict access to the review team, choose retention and regional policies appropriate for the repositories, and use a self-hosted or isolated deployment when required by policy. Backend retention and deletion are controlled by those services; disable tracing or remove the credentials when the review data must remain offline. Tracing metadata is correlation aid, not an authorization boundary.

GitHub Actions PR Review

The repository provides a reusable workflow that downloads Review Sheep into a directory separate from the PR checkout, installs it with uv, and calls the non-interactive scripts/review_pr.py. The Markdown Report is printed in the job log, appended to the GitHub Actions step summary, and published as a pull-request conversation comment. Later runs update the existing Review Sheep comment instead of creating duplicates.

The CI entrypoint receives an explicit CIConfig. The script is only an adapter from trusted environment values and command-line inputs; the Review path itself does not load a local .env file. This lets GitHub Actions and other CI callers inject credentials and provider settings without placing secrets in the checkout.

This repository also contains .github/workflows/review.yml, which runs the reusable workflow automatically for same-repository pull requests. Configure it with:

• Actions secret ANTHROPIC_AUTH_TOKEN contains the model provider's bearer token;
• Actions variable ANTHROPIC_BASE_URL contains the non-secret gateway URL, if any;
• optional Actions secret ANTHROPIC_CUSTOM_HEADERS contains Name: Value lines;
• optional Actions variables ANTHROPIC_DEFAULT_HAIKU_MODEL, ANTHROPIC_DEFAULT_OPUS_MODEL, and ANTHROPIC_DEFAULT_SONNET_MODEL override the built-in Claude model IDs; and
• optional Actions variables REVIEW_MODEL_TIER (haiku, sonnet, or opus, default sonnet) and REVIEW_INSTRUCTIONS control the Review.
• optional Actions secrets LANGFUSE_PUBLIC_KEY, LANGFUSE_SECRET_KEY, LANGFUSE_BASE_URL, and LANGFUSE_TRACING_ENVIRONMENT configure Langfuse;
• optional Actions secrets MLFLOW_TRACKING_URI and MLFLOW_EXPERIMENT_NAME configure MLflow; and
• set both backend groups to send one CI Review to both tracing systems.

If the gateway URL is sensitive, store it as ANTHROPIC_BASE_URL under Actions secrets instead of variables; the workflow accepts either source.

Fork pull requests are intentionally skipped because the pull_request event does not expose repository model secrets to untrusted forks.

Configure the Actions secrets and variables above in the repository being reviewed, then create .github/workflows/review-sheep.yml there:

name: Review Sheep

on:
  pull_request:
    types: [opened, synchronize, reopened]

permissions:
  contents: read
  pull-requests: write

jobs:
  review:
    # pull_request does not expose repository secrets to fork PRs.
    if: github.event.pull_request.head.repo.full_name == github.repository
    uses: taipingeric/review_sheep/.github/workflows/review-pr.yml@REVIEW_SHEEP_SHA
    with:
      # Use the same full commit SHA as the reusable workflow reference above.
      review_sheep_ref: REVIEW_SHEEP_SHA
      model_tier: sonnet
      anthropic_base_url: ${{ vars.ANTHROPIC_BASE_URL }}
      haiku_model: ${{ vars.ANTHROPIC_DEFAULT_HAIKU_MODEL || 'claude-haiku-4-5' }}
      opus_model: ${{ vars.ANTHROPIC_DEFAULT_OPUS_MODEL || 'claude-opus-4-6' }}
      sonnet_model: ${{ vars.ANTHROPIC_DEFAULT_SONNET_MODEL || 'claude-sonnet-4-6' }}
      # instructions: Focus on authorization and data integrity.
    secrets:
      ANTHROPIC_AUTH_TOKEN: ${{ secrets.ANTHROPIC_AUTH_TOKEN }}
      ANTHROPIC_BASE_URL: ${{ secrets.ANTHROPIC_BASE_URL }}
      ANTHROPIC_CUSTOM_HEADERS: ${{ secrets.ANTHROPIC_CUSTOM_HEADERS }}
      LANGFUSE_PUBLIC_KEY: ${{ secrets.LANGFUSE_PUBLIC_KEY }}
      LANGFUSE_SECRET_KEY: ${{ secrets.LANGFUSE_SECRET_KEY }}
      LANGFUSE_BASE_URL: ${{ secrets.LANGFUSE_BASE_URL }}
      LANGFUSE_TRACING_ENVIRONMENT: ${{ secrets.LANGFUSE_TRACING_ENVIRONMENT }}
      MLFLOW_TRACKING_URI: ${{ secrets.MLFLOW_TRACKING_URI }}
      MLFLOW_EXPERIMENT_NAME: ${{ secrets.MLFLOW_EXPERIMENT_NAME }}

Replace both REVIEW_SHEEP_SHA placeholders with the same full Review Sheep commit SHA. Pinning prevents workflow code and the downloaded Python package from drifting independently. Do not change this workflow to pull_request_target and then execute untrusted PR code with model secrets.

ANTHROPIC_AUTH_TOKEN is passed through the Anthropic SDK's bearer-token authentication path. ANTHROPIC_CUSTOM_HEADERS follows Claude Code's newline-separated Name: Value convention.

Gateway connections use a 10-second connect timeout with the Anthropic SDK's normal retries, while model responses may run for up to 10 minutes. A ConnectTimeout therefore indicates that the gateway cannot be reached from the GitHub runner; it is not a model-generation timeout. Private gateways need a self-hosted runner with network access or an endpoint reachable from GitHub's hosted runners.

The reusable workflow checks out the exact PR head with full Git history, so GitCheckoutSource can verify the head SHA and resolve the base commit before any Lens runs.

Publishing to PyPI

.github/workflows/publish.yml builds the sdist and wheel with uv build and uploads them to PyPI whenever a GitHub Release is published, or a v* tag is pushed. It authenticates with PyPI Trusted Publishing (OIDC), so no PyPI API token is stored as a repository secret.

Before the first release, a repository maintainer must sign in to pypi.org and add a pending publisher for the review-sheep project pointing at taipingeric/review_sheep and the publish.yml workflow. This is a one-time, manual step tied to a PyPI account and cannot be automated.