A context engineering tool for AI coding assistants.
Detects post-training knowledge gaps, resolves them automatically,
and delivers your team's decisions via MCP to Claude, Cursor, Copilot, and 10+ tools.
767 tests · 23 expert skills · 10 ecosystems · 11 languages · 14 AI tools
--- ## The Problem Your AI writes code using knowledge from its training data. Your project uses libraries released **after** that cutoff. The result: hallucinated APIs, deprecated patterns, and code that doesn't compile. Your team's decisions — use PaymentIntents, not Charges; always wrap API responses; never useEffect for data fetching — exist nowhere in the AI's training data. The code it generates is idiomatic React or idiomatic Node — just not idiomatic *yours*. When we asked Claude to write code for `botid` (published 2026-03-03, post-training): > *"I can't verify the botid package's actual API. **I won't output code for a package whose API I can't verify.** Guessing function names and signatures would likely give you broken code."* ## The Fix BookLib detects every post-training API in your codebase and resolves the gaps automatically.
booklib analyze on vercel/ai-chatbot — 82 dependencies, 274 post-training APIs across 158 files.
**Without BookLib** — AI uses AI SDK v5 patterns from training data:
```typescript
import { OpenAIStream, StreamingTextResponse } from 'ai'; // removed in v6
import OpenAI from 'openai';
export async function POST(req: Request) {
const response = await new OpenAI().chat.completions.create({
model: 'gpt-4', stream: true, messages,
});
return new StreamingTextResponse(OpenAIStream(response));
}
```
**With BookLib** — AI gets v6 docs injected at runtime:
```typescript
import { streamText, convertToModelMessages,
createUIMessageStreamResponse } from 'ai';
import { openai } from '@ai-sdk/openai';
export async function POST(req: Request) {
const result = streamText({
model: openai('gpt-4o'),
messages: convertToModelMessages(messages),
});
return createUIMessageStreamResponse({
stream: result.toUIMessageStream(),
});
}
```
---
## Getting Started
Requires Node.js >= 18.
```bash
npm install -g @booklib/core
booklib init
```
The wizard detects your stack, configures MCP for your AI tools, and builds the knowledge index. Then see what your AI doesn't know:
```bash
booklib analyze
```
Website and skill browser at [booklib-ai.github.io/booklib](https://booklib-ai.github.io/booklib/).
---
## How It Works
Most context tools wait for your AI to ask. BookLib detects gaps before coding starts and injects corrections as code is written.
### 1. Detect Knowledge Gaps
Scans your dependencies across npm, PyPI, Maven, Crates.io, RubyGems, Go modules, Packagist, Pub, Swift, and NuGet. Checks publish dates against the model's training cutoff, then cross-references with your source code to find the exact files and APIs affected.
### 2. Resolve Automatically
For each gap, BookLib fetches current documentation:
1. **Context7** — instant, version-specific library docs
2. **GitHub** — releases, wiki, and discussions
3. **Manual** — suggests the right `booklib connect` command
### 3. Protect at Runtime
PreToolUse and PostToolUse hooks inject context as your AI writes code:
- **Runtime injection** — 3-10 lines of relevant knowledge inserted before each edit, powered by a pre-computed context map
- **Import checking** — flags unknown APIs not in the index (11 languages)
- **Contradiction detection** — warns when code violates team decisions in real-time
### 4. Capture Team Knowledge
Your team's decisions live nowhere in public docs. BookLib auto-detects project documentation — specs, ADRs, architecture docs — and indexes them alongside your team decisions.
```bash
booklib capture --title "use PaymentIntents not Charges" --type decision
booklib connect notion database Claude Code · Cursor · Copilot · Gemini CLI · Codex · Windsurf · Roo Code · Goose · Zed · Continue · OpenHands · Junie · OpenCode · Letta
10 tools via MCP, 14 total with instruction-file support. See [AGENTS.md](./AGENTS.md) for per-tool setup. --- ## CLI Reference **Setup** | Command | Description | |---------|-------------| | `booklib init` | Guided setup — detects stack, configures MCP, builds index | | `booklib index` | Rebuild the search index | | `booklib doctor` | Health check for skills and config | **Daily use** | Command | Description | |---------|-------------| | `booklib gaps` | Find post-training dependencies | | `booklib resolve-gaps` | Auto-fix gaps via Context7 and GitHub | | `booklib analyze` | Show affected files and post-training APIs | | `booklib search "