stalemap

<p align="center">
  <img src=".github/assets/banner.svg" alt="stalemap: tell your coding agent which dependencies changed after its training cutoff" width="100%">
</p>

<p align="center">
  <a href="https://www.npmjs.com/package/stalemap"><img src="https://img.shields.io/npm/v/stalemap?color=f59e0b&label=npm" alt="npm version"></a>
  <a href="https://github.com/Umair/stalemap/actions/workflows/ci.yml"><img src="https://github.com/Umair/stalemap/actions/workflows/ci.yml/badge.svg" alt="CI"></a>
  <a href="LICENSE"><img src="https://img.shields.io/badge/license-MIT-22c55e" alt="MIT license"></a>
  <img src="https://img.shields.io/node/v/stalemap?color=64748b" alt="Node version">
  <a href="#claude-code-plugin"><img src="https://img.shields.io/badge/Claude_Code-plugin-d97757" alt="Claude Code plugin"></a>
  <a href="#any-mcp-client"><img src="https://img.shields.io/badge/MCP-server-6366f1" alt="MCP server"></a>
</p>

<p align="center">
  <a href="#install">Install</a> ·
  <a href="#what-the-notes-look-like">Example</a> ·
  <a href="#how-it-works">How it works</a> ·
  <a href="#results">Results</a> ·
  <a href="CHANGELOG.md">Changelog</a>
</p>

Coding agents learn libraries from training data that stops at a cutoff date. When your project pins newer versions, the agent writes code for the old API: `maxSteps` against AI SDK 7, `required_error` against zod 4, `middleware.ts` against Next 16.

stalemap finds the dependencies that changed after your model's training cutoff and tells the agent what changed, in three ways:

- **Notes:** a short, ranked list of changes written into `AGENTS.md` or `CLAUDE.md`, so the agent reads it before it starts.
- **Edit-time guard:** after each edit, the project's own type-check. If the code uses an API that changed after the cutoff, the agent gets the compiler error and the matching note (or the release-note or upgrade-guide section that explains it) right away. It also reports the code that still compiles but uses something that moved.
- **`search_changes`:** an MCP tool the agent can ask in its own words, such as "resolve alias in next.config", to get the matching changes with their sources.

It works for JavaScript and TypeScript projects, with Claude Code, Cursor, Codex, OpenCode or any MCP client.

**In a blind, pre-registered benchmark** of 66 tasks built from changes released after June 2026, `claude-sonnet-5-5` agents passed **89%** of sessions with stalemap, against **68%** with no help and **73%** with a plain `tsc --noEmit` hook after each edit. See [Results](#results).

<p align="center">
  <img src=".github/assets/how-it-works.svg" alt="Your pinned versions, what your code uses and your model's cutoff go in; stalemap diffs types, release notes and upgrade guides; your agent gets notes at session start, a guard after each edit, and search_changes on demand." width="100%">
</p>

## Status

- **npm:** the latest release is [`stalemap` 0.4.1](https://www.npmjs.com/package/stalemap): the build tested in held-out v4 (0.4.0), plus a one-line footer in the notes block. `npx stalemap`, the Claude Code plugin and the GitHub Action all run it. See the [changelog](CHANGELOG.md).
- The project is early, and maintained by one person.

## Install

### Claude Code plugin

```text
/plugin marketplace add Umair/stalemap
/plugin install stalemap@stalemap
```

The plugin adds:

- a SessionStart hook that puts the notes into Claude's context for the session's model (on startup, after `/clear` and after compaction; it writes no files);
- a PostToolUse hook that runs the edit-time guard after each Write or Edit;
- the stalemap MCP server and two skills (`/stalemap:sync` writes the notes block; `upgrade` tells Claude to look up a package's changes before using or upgrading it).

The hooks and the MCP server run `npx -y stalemap@latest`, so they use the latest npm release. Its MCP tools are `search_changes`, `package_changes`, `project_changes` and `check_notes`.

### Command line

```bash
npx stalemap            # preview what changed and the block it would write
npx stalemap sync       # write the block into AGENTS.md or CLAUDE.md
npx stalemap check      # for CI: exit 1 when the block is missing or stale
npx stalemap guard src/**/*.ts   # run the guard by hand
```

The block sits between `<!-- stalemap:start -->` and `<!-- stalemap:end -->`. Text outside it is never touched. Claude Code reads `CLAUDE.md`; if your notes live in `AGENTS.md`, add `@AGENTS.md` to `CLAUDE.md` or pass `--target CLAUDE.md`.

### Other agents: `setup --agent`

```bash
stalemap setup --agent cursor             # or codex, opencode, claude
stalemap setup --agent codex --dry-run    # print the changes, write nothing
```

One command per agent writes the notes, registers the MCP server and installs the guard as the agent's post-edit hook, as project files you can commit. It merges into existing config files, keeps entries it didn't write, and re-running it changes nothing.

One caveat: it hasn't been tried in a real Cursor, Codex or OpenCode install yet. Cursor doesn't pass a `postToolUse` hook's context to the model yet, so setup adds a stop-hook fallback that sends unreported findings as a follow-up message.

### Any MCP client

```json
{ "mcpServers": { "stalemap": { "command": "npx", "args": ["-y", "stalemap@latest", "mcp"] } } }
```

### GitHub Action

```yaml
- uses: Umair/stalemap@main
  with:
    model: claude-opus-5-5          # fail CI when the notes are missing or stale
    # mode: comment                 # or comment on PRs that change dependencies
```

Comment mode needs `permissions: pull-requests: write`. It lists each changed dependency (what the model knows → what's pinned) with its notes, and updates the comment on later pushes.

## What the notes look like

<p align="center">
  <img src=".github/assets/terminal.svg" alt="npx stalemap on a Next.js + AI SDK app with claude-sonnet-4-5: next, ai and zod changed after the cutoff, and the notes name the changed APIs and their replacements" width="100%">
</p>

For a Next.js + AI SDK app and `claude-sonnet-4-5` (cutoff 2025-07-31), excerpt:

```markdown
**ai** 4.3.16 → 7.0.142 (major)
- `CoreMessage` was removed; use `ModelMessage`. [types]
- `convertToCoreMessages` was removed; use `convertToModelMessages`. [types]
- `streamText()` options no longer accept `maxTokens`, `maxSteps`, `toolCallStreaming`, … [types]

**next** 15.4.0 → 16.4.2 (major)
- `revalidateTag()` now requires `profile` (in `next/cache`) [types]
- `NextMiddleware` is deprecated: Use `NextProxy` instead. Middleware has been renamed to Proxy. (in `next/server`) [types]
```

Full output: [examples/next-ai-app.claude-sonnet-4-5.md](examples/next-ai-app.claude-sonnet-4-5.md).

## How it works

1. **Which model?** `--model`, or the model configured for Claude Code, Codex, OpenCode or Gemini CLI, or `$ANTHROPIC_MODEL`. The training cutoff comes from [models.dev](https://models.dev) (with a built-in fallback table), or pass `--cutoff YYYY-MM-DD`.
2. **What did the model know?** For each dependency, the newest stable release published at least 30 days before the cutoff (`--margin`).
3. **Which dependencies?** Direct dependencies your code imports (scanned locally), plus the ones a config file configures (`tsconfig.json`, `next.config.*`, the Prisma schema, Vitest and ESLint configs, and others). `--all` checks every direct dependency. Pinned versions come from `node_modules` or the lockfile (npm, pnpm, yarn, bun).
4. **What changed?**
   - **Types:** both versions' `.d.ts` files are downloaded and compared with the TypeScript compiler API: removed, renamed and moved exports, new required parameters, removed or newly required options, and new `@deprecated` tags with their hints.
   - **Release notes:** the package's changelog or GitHub Releases, scored for breaking-change signals and for the APIs you use. A removal gets its replacement from a rename the changelog announces.
   - **Upgrade guides** (`--guides`): for changes that never reach a type signature, like a new default or a renamed file convention. Claude turns each guide into short notes, and a note is kept only if it quotes the guide.
   - **Verified examples** (`--examples`): a Before → After line under the top notes, written by Claude and kept only if it compiles against the version you pin.
5. **Fit the budget.** Notes about what your project uses come first: imported APIs, members and props, config keys it sets, file names. The default budget is 1,800 tokens (`--budget`).

**The guard** runs after each edit. It runs the project's own `tsc` and reports what it finds, in this order:

1. Compile errors that come from a dependency that changed after the cutoff, with the matching note as the fix. When no note explains the error, it shows the matching section from the package's type changes, release notes or upgrade guide, found by searching with the error and the code around it.
2. Things that still type-check but changed:
   - config keys that moved (`experimental.ppr` in Next 16);
   - moved members (`HttpStatusCode.PayloadTooLarge` → `ContentTooLarge` in axios 1.20);
   - renamed file conventions (`middleware.ts` → `proxy.ts`);
   - `tsconfig.json` options the project's TypeScript rejects.
3. The compiler's other errors: in the edited file, new ones in files that import it, and a few elsewhere. These don't claim a dependency changed.

So a plain type-check hook is a subset of the guard. `STALEMAP_GUARD_TSC=0` limits the guard to dependency changes. Deprecations are reported only with `STALEMAP_GUARD_DEPRECATIONS=1`.

**`search_changes`** (also `stalemap search <query>`) searches everything stalemap found for the project's dependencies: every type change, every release-note item, cached upgrade-guide notes and, for a new major, the guides' text. Ranking is BM25 over words and split identifiers (`resolveAlias` matches "resolve alias"), weighted toward what the project uses. The first search builds an index from the analysis caches; later on