resolveLibraryId - Context7 MCP

The resolveLibraryId tool searches Context7's library database and returns matching results with their Context7-compatible library IDs. This is typically the first step in a documentation lookup workflow.

Usage#

import { resolveLibraryId } from "@upstash/context7-tools-ai-sdk";import { generateText, stepCountIs } from "ai";import { openai } from "@ai-sdk/openai";const { text } = await generateText({  model: openai("gpt-5.2"),  prompt: "Find documentation for React hooks",  tools: {    resolveLibraryId: resolveLibraryId(),  },  stopWhen: stepCountIs(3),});

Configuration#

resolveLibraryId(config?: Context7ToolsConfig)

Parameters#

configContext7ToolsConfig#

Configuration options for the tool.

Show properties

apiKeystring#

Context7 API key. If not provided, uses the CONTEXT7_API_KEY environment variable.

Returns#

Returns an AI SDK tool that can be used with generateText, streamText, or agents.

Tool Behavior#

When the AI model calls this tool, it:

Takes a query and libraryName parameter from the model
Searches Context7's database for matching libraries
Returns formatted results including:
- Library ID (e.g., /reactjs/react.dev)
- Title and description
- Number of code snippets available
- Source reputation score
- Available versions

Input Schema#

The tool accepts the following input from the AI model:

querystringrequired#

The user's original question or task. This is used to rank library results by relevance to what the user is trying to accomplish.

libraryNamestringrequired#

Library name to search for (e.g., "react", "next.js", "vue")

Output Format#

On success, the tool returns the search results as plain text, formatted for easy consumption by the AI model:

- Title: React Documentation- Context7-compatible library ID: /reactjs/react.dev- Description: The library for web and native user interfaces- Code Snippets: 1250- Source Reputation: High- Benchmark Score: 98- Versions: 19.0.0, 18.3.1, 18.2.0----------- Title: React Native- Context7-compatible library ID: /facebook/react-native- Description: A framework for building native applications using React- Code Snippets: 890- Source Reputation: High- Benchmark Score: 95- Versions: 0.76.0, 0.75.4

On failure:

No libraries found matching "unknown-lib". Try a different search term or check the library name.

Examples#

Basic Usage#

import { resolveLibraryId, queryDocs } from "@upstash/context7-tools-ai-sdk";import { generateText, stepCountIs } from "ai";import { openai } from "@ai-sdk/openai";const { text, toolCalls } = await generateText({  model: openai("gpt-5.2"),  prompt: "What libraries are available for React?",  tools: {    resolveLibraryId: resolveLibraryId(),    queryDocs: queryDocs(),  },  stopWhen: stepCountIs(5),});// The model will call resolveLibraryId and receive a list of matching librariesconsole.log(text);

With Custom API Key#

import { resolveLibraryId } from "@upstash/context7-tools-ai-sdk";const tool = resolveLibraryId({  apiKey: process.env.CONTEXT7_API_KEY,});

Inspecting Tool Calls#

import { resolveLibraryId } from "@upstash/context7-tools-ai-sdk";import { generateText, stepCountIs } from "ai";import { openai } from "@ai-sdk/openai";const { toolCalls, toolResults } = await generateText({  model: openai("gpt-5.2"),  prompt: "Find the official Next.js documentation",  tools: {    resolveLibraryId: resolveLibraryId(),  },  stopWhen: stepCountIs(3),});// See what the model searched forfor (const call of toolCalls) {  console.log("Searched for:", call.input.libraryName);}// See the resultsfor (const result of toolResults) {  console.log("Found:", result.output);}

Selection Guidance#

The tool's description instructs the AI model to select libraries based on:

Name similarity - Exact matches are prioritized
Description relevance - How well the description matches the query intent
Documentation coverage - Libraries with more code snippets are preferred
Source reputation - High/Medium reputation sources are more authoritative
Benchmark score - Quality indicator (100 is the highest)

queryDocs - Fetch documentation using the resolved library ID
Context7Agent - Pre-built agent that handles the full workflow