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.

Features

GitHub-style math example

The preview uses the delimiter rules from Writing mathematical expressions: inline $…$, GitHub’s dollar-backtick inline form (rewritten to $…$ before parsing), display $$…$$, and fenced math code blocks. Rendering is KaTeX rather than GitHub’s MathJax, so a few uncommon macros can differ even when markdown syntax matches.

This app does not embed raw HTML in the markdown preview, so GitHub’s <span>$</span> workaround for literal dollar signs in prose is unavailable here—inside math, escape $ as \$ per GitHub’s docs.

Examples:

Inline: $\sqrt{3x-1}+(1+x)^2$

Dollar-backtick (GitHub-compatible): $e^{i\pi} + 1 = 0$

$$ \nabla_\theta J(\theta) = \mathbb{E}{(s, a) \sim \pi\theta} \left[\nabla_\theta \log \pi_\theta(a \mid s), R(s, a)\right] $$

WaveDrom example

Fenced ```wavedrom blocks are parsed as WaveJSON (via JSON5, so unquoted/single-quoted keys are fine) and rendered inline, with the same source/rendered toolbar toggle as Mermaid. Three diagram kinds are supported, selected automatically from the JSON shape:

A digital timing diagram (signal):

{signal: [
  {name: 'clk',  wave: 'p.....'},
  {name: 'data', wave: 'x.345x', data: ['head', 'body', 'tail']},
  {name: 'req',  wave: '0.1..0'},
  {name: 'ack',  wave: '1.....'}
]}

A bit-field / register diagram (reg):

{reg: [
  {bits: 7, name: 'opcode'},
  {bits: 5, name: 'rd'},
  {bits: 3, name: 'funct3'},
  {bits: 5, name: 'rs1'},
  {bits: 12, name: 'imm[11:0]'}
], config: {bits: 32}}

A logic / schematic diagram (assign):

{assign: [["z", ["|", "a", ["&", "b", "c"]]]]}

Related MCP server: reader3000-mcp

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"]
    AgentCli["Coding agent<br/>Claude Code / Cursor CLI / Codex<br/>`batch-review <verb>`"]

    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, per-client MCP sessions,<br/>connected WebSocket clients"]
    end

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

    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
    AgentCli -->|"REST `/api/*`"| Server
    AgentCli -.->|"reads for discovery"| PortFile
    Server -.->|"writes on start"| PortFile
    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. Every comment carries a userid; browser comments default to the Windows/Linux/macOS account running the server, while MCP connections and CLI profiles can change their own current userid.

• Multiple MCP clients can connect to one server concurrently. They share the collaborative comment collection, but each client gets an isolated application session and current userid; legacy FastMCP connections map their Context.session_id to that application session, while modern stateless clients pass its private ID explicitly.

• In --mcp mode, the HTTP server keeps the web UI available while FastMCP also runs over stdio for editor and CLI hosts.

• In CLI client mode, coding agents invoke batch-review <verb> (e.g. add-comment, diff) which calls the same REST endpoints — no MCP tool schemas loaded into agent context. The server writes .batch_review/server.json on startup so CLI verbs can discover it.

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).

Requirements

• Python ≥ 3.13 with uv

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

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).

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"]
    }
  }
}

CLI client mode (token-efficient agent interface)

For coding agents (Claude Code, Cursor CLI, Codex, etc.), the CLI client mode is more token-efficient than loading 18 MCP tool schemas into context. Each verb is one process invocation that emits a single JSON document to stdout. The CLI talks to a running server over REST, so every comment and highlight also appears in the human reviewer's browser UI in real time.

# Start the server in the background (browser opens by default)
batch-review start --root .
# {"web_url": "http://127.0.0.1:9000", "pid": 12345, "port": 9000}

# List changed files
batch-review changes
# [{"path": "main.py", "status": "M", ...}, ...]

# Inspect a diff
batch-review diff main.py

# Identity defaults to the OS account running the command; change it when needed
batch-review get-userid
batch-review set-userid reviewer-a

# Add a comment anchored to a line range (captures the current userid)
batch-review add-comment main.py 10 15 "This null check is redundant."

# Save the review report (JSON + Markdown)
batch-review save

# Stop the server when done
batch-review stop

Server discovery — verbs auto-discover a running server in priority order: the BATCH_REVIEW_WEB_URL env var, then <repo_root>/.batch_review/server.json (written by start), then probing ports 9000–9999.

CLI identity — get-userid and set-userid manage the userid attached to new CLI comments. The default is the local OS account from Python's cross-platform account lookup. Profiles are stored independently under .batch_review/users/; use --profile NAME or BATCH_REVIEW_USER_PROFILE when multiple agents share one checkout. BATCH_REVIEW_USERID or add-comment --userid ID overrides the selected profile for one process/request. Userids may contain printable international text (maximum 256 characters), but non-printable Unicode, formatting, and non-ASCII separator characters are rejected. Userids are attribution metadata, not authentication.

Verb reference — all verbs accept --root PATH (default: cwd):

Output contract: JSON on stdout, progress messages on stderr, non-zero exit on error. The start verb is backward-compatible — if a server is already running, it reports the existing URL instead of starting a duplicate.

Claude Code plugin

This repo ships a Claude Code plugin (CLI-only — no MCP server entry, so agents don't load tool schemas into context). Install it from the marketplace:

/plugin marketplace add hevangel/batch-review-mcp
/plugin install batch-review@batch-review

The plugin bundles:

• Skill (skills/batch-review/SKILL.md) — teaches the agent the review workflow using CLI verbs.

• Command (commands/batch-review.md) — a /batch-review slash command that triggers the skill.

• Plugin manifest (.claude-plugin/plugin.json) + marketplace (.claude-plugin/marketplace.json).

Agent skill (skills.sh)

The review-workflow skill is also installable into any agent that supports the open Agent Skills standard (Claude Code, Cursor, Codex, Gemini CLI, Copilot, ZCode, and 60+ others) via the npx skills CLI:

# Install globally (available across all your projects)
npx skills add hevangel/batch-review-mcp --global --yes

# Or install into a specific agent only
npx skills add hevangel/batch-review-mcp --skill batch-review --agent claude-code --global

# List available skills without installing
npx skills add hevangel/batch-review-mcp --list

Once installed, the skill auto-triggers when you ask your agent to review code, inspect diffs, or leave review comments. Discovery and listing on skills.sh happens automatically via install telemetry — there is no manual submission step.

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).

2. Commit and push that release-prep change to main.

3. Push the tag (e.g. git tag v0.4.3 && git push origin v0.4.3).

4. The Release workflow builds the Linux artifacts again, runs scripts/update_server_json_mcpb_sha.py to patch server.json in the workflow workspace from the Linux-built .mcpb, runs scripts/verify_release_mcp_registry.py, creates or updates the GitHub release, publishes server.json to the MCP Registry via GitHub Actions OIDC (mcp-publisher login github-oidc), and publishes the wheel/sdist to PyPI when PYPI_API_TOKEN is configured. If identifier or versions do not match the tag, or if the patched server.json still does not match the Linux-built .mcpb, the job fails so you never publish a broken asset to the registry.

The separate MCP registry preflight (Linux MCPB hash) workflow is now optional. It is still useful when you want to inspect the Linux-built bundle bytes before tagging or debug a registry mismatch, but normal releases no longer require copying a SHA into server.json by hand.

Both CI workflows install frontend dependencies with npm ci --legacy-peer-deps. The frontend intentionally pins react-pdf/pdfjs-dist to 4.8.69 while the optional PDF.js peer declared by @aiden0z/pptx-renderer targets >=5 <7; plain npm ci fails peer resolution under the Node 22/npm 10 environment used by GitHub Actions. The Office PDF fallback is disabled, so accepting the locked dependency tree does not change the application bundle.

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. That rerun path also repairs MCP Registry publication because the workflow republishes server.json from the current main branch metadata and recomputes the Linux fileSha256 before verify/publish.

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.

Local mcp-publisher login github remains useful for one-off manual publishes, but normal tagged releases no longer require workstation device-code confirmation.

CLI flags

The batch-review command dispatches on its first argument: if it's a known CLI verb (start, stop, changes, diff, add-comment, etc.), it runs as a token-efficient client that talks to a running server over REST. Otherwise, it runs as the server with these flags:

See CLI client mode above for the full verb reference, or run batch-review --help.

UI Walkthrough

Left panel — two tabs

Files tab — lazy directory tree. The first render loads only the first few levels so large repositories stay responsive; expanding a folder loads its children on demand while deeper folders continue hydrating in the background. Click a file to open it in the center panel. Expand all and Collapse all share the file-tree toolbar; their text labels collapse to icons with tooltips when the resizable left panel is narrow.

The top bar also includes a theme toggle next to the reload control. The app starts in dark mode and remembers your light/dark choice in the browser.

Git tab — lists files changed relative to the active compare mode with status badges:

• 🟡 M modified

• 🟢 A added

• 🔴 D deleted

• ⚪ U untracked

Use Local for working tree/index changes vs HEAD, Commit for a previous commit/ref vs current HEAD, or PR for current checkout vs a GitHub PR head (enter a PR number or URL). Click a changed file to open it in inline diff mode with labels for the selected left and right sides.

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 with a toolbar toggle between rendered preview and Markdown source. Relative image embeds render inline, GitHub-compatible math syntax (KaTeX) supports inline $…$, dollar-backtick inline, display $$…$$, and fenced math blocks (GitHub docs), Mermaid fenced blocks can switch between rendered diagrams and raw source via the center-panel toolbar, WaveDrom fenced blocks (```wavedrom) render digital timing diagrams, bit-field/register diagrams (reg), and logic/schematic diagrams (assign) with the same source/rendered toolbar toggle, 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.

• HTML files — rendered in a sandboxed preview with scripts disabled and a toolbar toggle back to source. Hover/click rendered elements or select rendered text to create comments anchored to the source HTML line range plus an element selector/fingerprint; use Region mode for visual layout issues, which stores a normalized rendered-page rectangle and a PNG crop saved beside the review JSON. Repo-local CSS and image assets load through a safe raw-content endpoint.

• 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 and save a PNG crop beside the review JSON (Ctrl+Alt+C).

• DOCX files — rendered locally as best-effort Word pages in the browser and scaled down to fit the available center-panel content width while preserving page proportions; the fit calculation includes rendered page descendants, including equations and vector graphics, so wide content is included before scaling. Select text for a page-aware document anchor, or switch to Region mode to comment on a visual page region; the selected region is captured as a PNG saved beside the review JSON/Markdown output. This uses docx-preview; complex Word layout and pagination can differ from Microsoft Word, and document anchors are retained as best-effort fingerprints rather than backend-verified stale text ranges.

• PPTX files — rendered locally as browser-native slides using @aiden0z/pptx-renderer. Select text where the browser renderer exposes it, or use Region mode for a slide rectangle; selected slide regions are captured as PNG files saved beside the review JSON/Markdown output. Embedded EMF/PDF fallback rendering is disabled to keep the existing PDF.js 4.x dependency unchanged.

• Office diffs — DOCX/PPTX changes are reported as binary packages instead of raw ZIP/XML diffs. Open the current document viewer for visual review; semantic old/new document diffing is not yet provided.

• Code files — Monaco Editor with syntax highlighting. Select lines and click + Add Comment in the toolbar.

• Diff view — Monaco DiffEditor showing the selected compare sides 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

• The comment userid when identity display is enabled

• 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 Comments header shows the path sort control, path filter, and (for mixed-user reviews) user filter in its first row. When the panel enters its compact control width, all three controls move below the title as one group; at narrower widths, the path and user filters use separate rows while sort stays beside the path filter. If every comment belongs to the same userid as the account running the server, redundant IDs are hidden automatically. Blind review / Show IDs, Reload, Outdated, and Clear all share one action row. Use Blind review / Show IDs to explicitly hide or reveal attribution; blind mode also removes and resets the user filter so it cannot leak reviewer identity. When the resizable panel becomes too narrow, action text hides before the icons while tooltips and accessible labels remain; both side panels stop shrinking at the width required by four compact icon buttons. On initial load, the app makes both side panels wide enough to show their toolbar labels whenever doing so still leaves at least half of the viewport for the center panel; smaller viewports retain the compact defaults.

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

Rendered HTML, PDF, DOCX, and PPTX region screenshots are saved as PNG files in the same output directory and referenced by filename from the matching JSON comment (and copied alongside custom output paths).

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.

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 init_batch_review_session(coding_agent, model_name?, client_version?, userid?) and retain its returned session_id

2. Pass session_id to later calls when using modern stateless MCP (legacy connection-scoped clients may omit it)

3. Optionally call set_current_userid(userid, session_id?) when the reviewer identity changes

4. Call get_git_changes(session_id?)

5. Call get_git_diff(path, session_id?) for files worth reviewing

6. Use get_file_content(path, session_id?) only when extra non-diff context is needed

7. Add or update comments, optionally driving the shared UI with open/highlight/jump tools

8. Save or load the review session with the review file tools

Protocol compatibility

This server now uses fastmcp 4.0.2 with the MCP Python SDK 2.x (mcp>=2.0.0,<3.0). FastMCP 4 supports both MCP protocol eras, so existing hosts can continue using the legacy connection-scoped initialize handshake while modern clients use the stateless protocol path.

The legacy era uses protocol revision 2025-11-25 and Mcp-Session-Id session management for streamable HTTP. The MCP spec's modern revision 2026-07-28 replaces that handshake with per-request _meta.io.modelcontextprotocol/* fields, adds MCP-Protocol-Version / Mcp-Method / Mcp-Name headers to streamable HTTP, and requires server/discover. FastMCP and the MCP SDK own this negotiation and transport behavior; Batch Review does not add a competing protocol-compatibility layer.

FastMCP 4.0.2 also requires the newer Starlette generation, so the project declares fastapi>=0.133.0 and uvicorn[standard]>=0.35.0 alongside the FastMCP upgrade. The exact reproducible versions are recorded in uv.lock, currently FastMCP 4.0.2 and MCP 2.1.1.

The active protocol version is surfaced in the get_config MCP tool and the GET /api/config REST endpoint under a protocol key:

{
  "active_protocol_version": "2026-07-28",
  "supported_protocol_versions": ["2025-11-25", "2026-07-28"],
  "pending_protocol_versions": [],
  "modern_era_available": true
}

The single source of truth for these values is backend/mcp_compat.py.

Multi-client session and userid scheme

One Batch Review server process supports multiple simultaneous stdio/HTTP MCP clients and browser/CLI users:

• init_batch_review_session returns a random application session_id. It is a private bearer capability returned only to the initializing caller: shared config, WebSocket presence events, and logs expose display metadata but never session IDs or per-session userids. Modern stateless clients pass it to every later gated tool.

• Legacy stdio/HTTP connections may omit the application ID because Batch Review privately maps FastMCP's connection Context.session_id to the same application session. REST/CLI session initialization also generates IDs server-side, and duplicate registration is rejected rather than overwriting an existing session.

• get_current_userid(session_id?) and set_current_userid(userid, session_id?) read or change only that application session. add_comment(..., session_id?) copies the current value into the comment's immutable attribution field. A later identity change affects only future comments.

• All gated MCP tools accept the optional application session_id, so modern requests do not depend on cross-request transport state. A server process accepts up to 256 application sessions and rejects additional initialization instead of invalidating an existing private capability; restart the server to clear the registry. Public metadata is not a durable or disconnect-aware presence list.

• Browser/REST comments with no explicit userid use the server process account. CLI calls resolve an independent local profile and send the userid on every add request, so short-lived CLI processes do not depend on mutable server-global identity.

• Comments, loaded review files, saves, and WebSocket broadcasts remain intentionally shared across sessions: this is one collaborative review, not a private review per user. Destructive operations still affect the shared review.

This is concurrency-safe for identity in the supported single Python process. Separate Batch Review processes do not share memory or coordinate writes to the same output file. Also, userid is self-asserted attribution on this local unauthenticated app; it is not authorization. Deployments requiring trusted identities, permissions, or multi-process scaling should add authentication and a shared transactional store.

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 before review tools (with a non-empty coding_agent, e.g. Cursor or Claude Desktop, and optionally userid) and retain the returned application session_id. Modern stateless clients pass that value to every later gated tool; legacy connection-scoped clients can omit it. The default userid is the account running the Batch Review server; use set_current_userid whenever an agent needs to attribute future comments to a different reviewer.

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).

Output formats

JSON (review_comments.json)

Every saved comment includes userid. Older JSON files without it remain loadable and are assigned the account running the server when loaded, so the next save writes the complete schema.

[
  {
    "id": "4c66b5fc-...",
    "userid": "reviewer-a",
    "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": "…",
    "region_screenshot_file": null,
    "region_screenshot_width": null,
    "region_screenshot_height": null,
    "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)_

---

## src/auth.py

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

---

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

For contributor documentation, name session_history/ files with the actual date of the AI session that produced the change rather than copying the date from an older entry.

License

MIT