Batch Review MCP Server

Batch Review

A collaborative code and markdown review tool that bridges human reviewers and AI agents. Both can browse files, inspect git diffs, leave structured comments, and save a final review report — all from the same UI, in real time.

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Features

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Architecture

At runtime, Batch Review is a single Python application that serves the browser UI, exposes REST and WebSocket endpoints for that UI, and optionally exposes the same review session to MCP clients.

flowchart LR
    CLI["CLI entry point<br/>`uv run batch-review`"]
    Browser["Browser UI<br/>React + Zustand"]
    McpHost["MCP host<br/>Cursor / Claude Desktop / VS Code / other clients"]

    subgraph Backend["Batch Review backend process"]
        Server["FastAPI app<br/>static frontend `/`<br/>REST `/api/*`<br/>WebSocket `/ws`"]
        Mcp["FastMCP server<br/>stdio transport<br/>HTTP transport `/mcp`"]
        State["Shared AppState<br/>repo root, comments, MCP session,<br/>connected WebSocket clients"]
    end

    Repo["Git repository under review"]
    Output["Saved review output<br/>`review_comments.json`<br/>`review_comments.md`"]

    CLI --> Server
    CLI --> Mcp
    Server --> Browser
    Browser -->|"REST reads/writes"| Server
    Browser <-->|"live sync"| Server
    Server --> State
    Mcp --> State
    McpHost -->|"stdio or HTTP MCP"| Mcp
    State -->|"read files, diffs, existing review data"| Repo
    State -->|"save/load review reports"| Output
    State -.->|"broadcast UI events"| Browser

• The browser loads the React app from the FastAPI server, fetches files/comments/config over REST, and stays synchronized through /ws.
• MCP tools and REST routes both operate on the same in-memory AppState, so agent-created comments appear in the UI immediately.
• In --mcp mode, the HTTP server keeps the web UI available while FastMCP also runs over stdio for editor and CLI hosts.

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Distribution

• PyPI — batch-review-mcp — published wheels and sdist for pip / uv.
• Official MCP Registry — io.github.hevangel/batch-review-mcp — latest published server metadata (JSON API; the registry site is still preview).

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Requirements

• Python ≥ 3.13 with uv
• Node.js ≥ 22 (for the one-time frontend build; matches GitHub Actions)

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Installation

git clone https://github.com/hevangel/batch-review-mcp.git
cd batch-review-mcp
uv sync

The first run will automatically build the React frontend if frontend/dist/ does not exist (requires Node.js + npm on PATH).

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Usage

Standalone mode (browser opens by default)

# Review the current directory
uv run batch-review

# Review a specific git repository
uv run batch-review --root /path/to/your/repo

# Custom host / port
uv run batch-review --root /path/to/repo --host 0.0.0.0 --port 9100

# Specify output filenames
uv run batch-review --root /path/to/repo --output review --output-dir /tmp/reviews
# → saves /tmp/reviews/review.json and /tmp/reviews/review.md

The server auto-selects a free port in the 9000–9999 range if the default port is already in use.

MCP stdio mode (Claude Desktop / Cursor / any MCP client; browser opens by default)

uv run batch-review --mcp --root /path/to/repo

The HTTP server starts in a background thread (so the browser UI remains accessible), your default browser opens to the app URL (same as standalone mode; use --no-browser to skip), and the MCP stdio transport runs in the main thread.

Claude Desktop config (claude_desktop_config.json):

{
  "mcpServers": {
    "batch-review": {
      "command": "uv",
      "args": ["run", "batch-review", "--mcp", "--root", "/path/to/repo"]
    }
  }
}

Official MCP registry

This project includes a root-level server.json for the Model Context Protocol registry (preview). The entry uses registryType": "mcpb": the download URL must be a public GitHub release asset, and fileSha256 must match those bytes exactly (the Release workflow builds the .mcpb on Linux, which can differ from a pack produced on Windows).

Recommended order for a new version (e.g. v0.4.3):

1. Bump version in pyproject.toml, mcpb/manifest.json, and server.json (top-level version plus packages[0].identifier URL: .../releases/download/v0.4.3/batch-review-mcp-0.4.3.mcpb). The pack script pins @anthropic-ai/mcpb in scripts/build_mcpb.py so npm exec does not float to unrelated CLI majors; byte-identical .mcpb hashes can still differ from ubuntu-latest (Node/npm, line endings, etc.), so prefer the preflight SHA from GitHub Actions when cutting a release.
2. In GitHub Actions, run MCP registry preflight (Linux MCPB hash) (workflow_dispatch). Open the job summary and copy the printed SHA-256 into server.json → packages[0].fileSha256. Commit and push to main.
3. Push the tag (e.g. git tag v0.4.3 && git push origin v0.4.3). The Release workflow runs scripts/verify_release_mcp_registry.py before uploading; if identifier, versions, or fileSha256 do not match the Linux-built .mcpb, the job fails so you never publish a broken asset to the registry.
4. After the release exists, run mcp-publisher publish (with mcp-publisher and mcp-publisher login github). Optional: add PYPI_API_TOKEN so the same workflow can uv publish the wheel/sdist.

If a tag already exists but the Release workflow itself needed a workflow-only fix, you can rerun it manually from Actions via workflow_dispatch by providing release_tag (for example v0.4.3). That manual path checks out the tag you name, overlays the current release metadata from main, and reuses the existing tag name, so you can recover the release without moving the tag or rebuilding from a different code revision.

scripts/build_mcpb.py rewrites the packed archive deterministically after mcpb pack, so the Linux SHA from preflight should match the Linux SHA seen again in the Release workflow for the same source tree.

CLI flags

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UI Walkthrough

Left panel — two tabs

Files tab — recursive directory tree. Click a file to open it in the center panel.

Git tab — lists files changed relative to HEAD with status badges:

• 🟡 M modified
• 🟢 A added
• 🔴 D deleted
• ⚪ U untracked

Click a changed file to open it in inline diff mode.

Center panel

• No file selected — shows a lightweight getting-started panel with the app title and a short reminder: open a file or diff on the left, add comments, then save the review.
• Markdown files — fully rendered. Relative image embeds render inline, Mermaid fenced blocks can switch between rendered diagrams and raw source via the center-panel toolbar, links to other repo files open in the app, and links like other.md#heading open that file and jump to the heading in the center panel.
• PDF files — rendered page-by-page in the center panel. Text-selection comments remember the highlighted text on that page even if you click the toolbar Add button, while region comments keep a page rectangle (Ctrl+Alt+C).
• Code files — Monaco Editor with syntax highlighting. Select lines and click + Add Comment in the toolbar.
• Diff view — Monaco DiffEditor showing original (HEAD) vs working tree inline (red = removed, green = added). Switch back to normal view via the Git tab or by clicking the file in the Files tab.

Right panel

Each comment shows:

• @filename:L10-15 reference — click to jump to that location in the center panel
• A text area for your review notes (auto-saves on blur)
• For outdated text comments, a refresh icon inside the textbox that re-captures the current highlighted text at that line range and clears the outdated state
• A delete button

The 💾 Save Review button saves all comments to:

• {output-dir}/{output}.json — machine-readable JSON array
• {output-dir}/{output}.md — human-readable Markdown report grouped by file

When the server starts, if that JSON file already exists it is loaded into the session so you can continue a saved review (invalid files are skipped with a log warning). Loading a saved review from the right-panel folder button also updates the active review stem shown in the footer so subsequent saves target that loaded review name by default.

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MCP Tools

AI agents connect via http://localhost:PORT/mcp (HTTP transport) or stdio (--mcp flag).

The MCP surface is intentionally review-first. Batch Review is not trying to be a general repo browser or editor API; it is a shared review-state server for:

• identifying the review scope
• inspecting diffs and just enough file context
• adding or updating anchored review comments
• saving or resuming the review session

A typical agent flow is:

1. Call get_git_changes()
2. Call get_git_diff(path) for files worth reviewing
3. Use get_file_content(path) only when extra non-diff context is needed
4. Add or update comments, optionally driving the shared UI with open/highlight/jump tools
5. Save or load the review session with the review file tools

Repo-local MCP host configuration

This repository includes checked-in defaults so common agents can use Batch Review and Playwright together:

All definitions run uv run batch-review --mcp --root . --skip-build so the review root is the workspace directory hosts use as the server cwd. Cursor’s agent CLI does not always expand ${workspaceFolder} inside args, so these configs use "." for --root (VS Code may still use ${workspaceFolder} in .vscode/mcp.json, which that host expands).

Verifying stdio MCP

# Smoke test with the official Python MCP client
uv run python scripts/test_mcp_client.py

# Cursor Agent CLI (after install: https://cursor.com/docs/cli )
cd /path/to/batch_review_mcp
agent mcp enable batch-review
agent mcp list-tools batch-review
agent --approve-mcps -p "Your prompt that may call MCP tools"

Agents should call init_batch_review_session immediately after connecting (with a non-empty coding_agent, e.g. Cursor or Claude Desktop). The server enforces this: calling any other tool first yields a clear “call init…” error.

Comment add, update, delete, clear_all_comments, delete_outdated_comments, recompute_comment_stale, and load_review_by_stem also push a dismissible toast at the bottom of the right panel (similar styling to the post-save path hints).

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Output formats

JSON (review_comments.json)

[
  {
    "id": "4c66b5fc-...",
    "file_path": "src/auth.py",
    "line_start": 42,
    "line_end": 55,
    "reference": "@src/auth.py:L42-55",
    "text": "Token is never validated — add expiry check.",
    "highlighted_text": "…",
    "outdated": false,
    "created_at": "2026-04-15T10:00:00+00:00"
  }
]

Markdown (review_comments.md)

# Code Review

_Generated: 2026-04-15 10:00 UTC — 3 comment(s)_

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## src/auth.py

### `@src/auth.py:L42-55`
> Token is never validated — add expiry check.

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Development

# Backend only (no frontend build needed)
uv run batch-review --root . --skip-build --no-browser

# Frontend dev server (proxies API to port 9000)
cd frontend && npm run dev

# Full production build
cd frontend && npm run build

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License

MIT