# Troubleshooting Documentation Retrieval Failures in Context7: A Complete Guide

> Resolve Context7 documentation retrieval failures with this guide. Learn to troubleshoot API authentication, library IDs, and documentation states by tracing requests through the architecture.

- Repository: [Upstash/context7](https://github.com/upstash/context7)
- Tags: how-to-guide
- Published: 2026-02-16

---

**Context7 documentation retrieval failures typically stem from API authentication issues, invalid library identifiers, or unprocessed documentation states, and can be diagnosed by tracing requests through the four-layer architecture from the AI SDK tools down to the HTTP client.**

When working with the [upstash/context7](https://github.com/upstash/context7) repository, understanding how documentation flows from the API to your application is essential for effective debugging. The system processes requests through a layered pipeline: the **tool layer** (`queryDocs`), the **SDK layer** (`Context7#getContext`), the **command layer** (`GetContextCommand`), and finally the **MCP/API layer** (`fetchLibraryContext`). Failures can occur at any stage, requiring specific diagnostic approaches for each scenario.

## Understanding the Documentation Retrieval Architecture

Before diving into specific failures, it helps to visualize the request lifecycle:

1. **Tool Layer** – The `queryDocs` function in [`packages/tools-ai-sdk/src/tools/query-docs.ts`](https://github.com/upstash/context7/blob/main/packages/tools-ai-sdk/src/tools/query-docs.ts) validates input parameters and forwards requests to the SDK client.
2. **SDK Layer** – The `Context7` class in [`packages/sdk/src/client.ts`](https://github.com/upstash/context7/blob/main/packages/sdk/src/client.ts) creates a `GetContextCommand` and executes it via the `HttpClient`.
3. **Command Layer** – `GetContextCommand` in [`packages/sdk/src/commands/get-context/index.ts`](https://github.com/upstash/context7/blob/main/packages/sdk/src/commands/get-context/index.ts) constructs the `/v2/context` API request and formats the response as either JSON or plain text.
4. **MCP/API Layer** – The `fetchLibraryContext` function in [`packages/mcp/src/lib/api.ts`](https://github.com/upstash/context7/blob/main/packages/mcp/src/lib/api.ts) performs the actual HTTP fetch, parses errors via `parseErrorResponse`, and handles proxy configurations.

## Common Failure Scenarios and Solutions

### Invalid or Missing API Key

**Symptoms:** Errors such as "Invalid API key" or "API key is required."

The `Context7` constructor in [`packages/sdk/src/client.ts`](https://github.com/upstash/context7/blob/main/packages/sdk/src/client.ts) checks for `process.env.CONTEXT7_API_KEY` or an explicit `apiKey` option. If authentication fails, `parseErrorResponse` in [`packages/mcp/src/lib/api.ts`](https://github.com/upstash/context7/blob/main/packages/mcp/src/lib/api.ts) returns a 401 message.

**Troubleshooting steps:**
- Verify that `CONTEXT7_API_KEY` is set in your environment (`echo $CONTEXT7_API_KEY`).
- Ensure the key starts with the required `ctx7sk` prefix (defined as `API_KEY_PREFIX` in [`client.ts`](https://github.com/upstash/context7/blob/main/client.ts)).
- Regenerate a key from the Context7 dashboard if the current key is revoked or expired.

### Wrong Library ID Format

**Symptoms:** "No documentation found for library …" or "The library you are trying to access does not exist."

The library identifier must be a Context7-compatible path (e.g., `/facebook/react`, `/vercel/next.js/v14.3.0-canary.87`). The `GetContextCommand` in [`packages/sdk/src/commands/get-context/index.ts`](https://github.com/upstash/context7/blob/main/packages/sdk/src/commands/get-context/index.ts) passes this to the API without validation, causing failures if the format is incorrect.

**Troubleshooting steps:**
- Use the `resolveLibraryId` tool first; it returns a validated ID.
- If supplying the ID manually, double-check the leading slash and case-sensitivity.
- When using the SDK directly, call `client.searchLibrary` to explore available IDs.

### Documentation Not Yet Generated or Empty Results

**Symptoms:** The API returns an empty string or `null`. The SDK surfaces "Documentation not found or not finalized for this library …".

This occurs when the library exists but Context7 hasn't processed its documentation yet (new version, private repository, etc.).

**Troubleshooting steps:**
- Switch the request type to `txt` (default is `json`). In `queryDocs`, set `type: "txt"` through the SDK options.
- Retry after a short delay; generation may be asynchronous.
- Verify that the library is public and supported by checking the Context7 UI or `searchLibrary` results.

### Rate Limiting and Quota Exhaustion

**Symptoms:** "Rate limited or quota exceeded" message.

The API responds with HTTP 429, and `parseErrorResponse` in [`packages/mcp/src/lib/api.ts`](https://github.com/upstash/context7/blob/main/packages/mcp/src/lib/api.ts) builds a specific message for this status.

**Troubleshooting steps:**
- Wait for the reset period (usually a minute) and retry.
- Upgrade your plan or request a higher quota from the Context7 dashboard.
- Reduce parallel requests; the SDK's `HttpClient` in [`packages/sdk/src/http/index.ts`](https://github.com/upstash/context7/blob/main/packages/sdk/src/http/index.ts) automatically retries with exponential back-off, but you can limit retry attempts via the `retry` config.

### Network and Proxy Issues

**Symptoms:** Request hangs, "Failed to fetch" errors, or console logs about proxy configuration.

The API call goes through a proxy defined by `HTTPS_PROXY`, `HTTP_PROXY`, etc. (`PROXY_URL` handling in [`packages/mcp/src/lib/api.ts`](https://github.com/upstash/context7/blob/main/packages/mcp/src/lib/api.ts)).

**Troubleshooting steps:**
- Confirm that `HTTPS_PROXY` (or related) environment variables point to a reachable proxy.
- If a proxy isn't needed, unset those variables (`unset HTTPS_PROXY`).
- Validate outbound connectivity to `https://context7.com/api` (defined in [`packages/mcp/src/lib/constants.ts`](https://github.com/upstash/context7/blob/main/packages/mcp/src/lib/constants.ts) as `CONTEXT7_API_BASE_URL`).

### Unexpected Server Errors (5xx)

**Symptoms:** Generic "Request failed with status 500/502/503" messages.

These indicate transient server-side problems; `parseErrorResponse` falls back to a generic status-based message when it doesn't recognize the specific error code.

**Troubleshooting steps:**
- Retry after a brief back-off period.
- Check the Context7 status page (if available) for incidents.
- If the problem persists, open a support ticket with the request details and the raw response (excluding any secrets).

### SDK Misconfiguration

**Symptoms:** Errors thrown before the HTTP request, such as "Request did not return a result".

`GetContextCommand` in [`packages/sdk/src/commands/get-context/index.ts`](https://github.com/upstash/context7/blob/main/packages/sdk/src/commands/get-context/index.ts) expects a non-undefined `result`. This can happen if the underlying `HttpClient` receives an unexpected payload.

**Troubleshooting steps:**
- Ensure you're using the latest SDK version (`pnpm i @upstash/context7`).
- Enable debugging (`DEBUG=context7:*`) to inspect the raw response.
- Verify that the request path (`v2/context`) and query parameters (`query`, `libraryId`, `type`) are correct.

## Code Examples for Debugging

### Using the AI-SDK `queryDocs` Tool (Typical LLM Workflow)

```typescript
import { resolveLibraryId, queryDocs } from "@upstash/context7-tools-ai-sdk";
import { generateText, stepCountIs } from "ai";
import { openai } from "@ai-sdk/openai";

const { text } = await generateText({
  model: openai("gpt-4o"),
  prompt: "Explain how to enable JWT auth in Express.js",
  tools: {
    resolveLibraryId: resolveLibraryId(),
    queryDocs: queryDocs(),
  },
  // Stop after the tool chain finishes
  stopWhen: stepCountIs(5),
});

console.log(text);

```

The tool automatically calls `resolveLibraryId` first, validates the library ID, then invokes `queryDocs`. Errors from the API are returned as plain-text messages (see [`packages/tools-ai-sdk/src/tools/query-docs.ts`](https://github.com/upstash/context7/blob/main/packages/tools-ai-sdk/src/tools/query-docs.ts)).

### Direct SDK Usage with Explicit Error Handling

```typescript
import { Context7 } from "@upstash/context7-sdk";

const client = new Context7({ apiKey: process.env.CONTEXT7_API_KEY });

async function fetchDocs() {
  try {
    // Request plain-text documentation
    const docs = await client.getContext(
      "How to configure CORS in Next.js API routes",
      "/vercel/next.js",
      { type: "txt" }
    );
    console.log(docs);
  } catch (err) {
    // Handles API-level errors (invalid key, rate limit, etc.)
    console.error("Documentation fetch failed:", err);
  }
}

fetchDocs();

```

The SDK forwards the call to `GetContextCommand`, which in turn uses `fetchLibraryContext` (see [`packages/mcp/src/lib/api.ts`](https://github.com/upstash/context7/blob/main/packages/mcp/src/lib/api.ts)). Any HTTP error is converted into a human-readable string via `parseErrorResponse`.

### Inspecting Low-Level API Response (Debugging)

```typescript
import { fetchLibraryContext } from "@upstash/context7-mcp";
import { CONTEXT7_API_BASE_URL } from "@upstash/context7-mcp/constants";

async function debugFetch() {
  const response = await fetchLibraryContext(
    { query: "setup auth", libraryId: "/expressjs/express" },
    { apiKey: process.env.CONTEXT7_API_KEY }
  );
  console.log("Raw response:", response);
}

```

Use the MCP layer directly to see the exact JSON or error string returned by the backend. This is useful when the SDK's formatting masks the underlying issue.

## Key Files for Troubleshooting

| File | Purpose | Link |
|------|---------|------|
| [`packages/tools-ai-sdk/src/tools/query-docs.ts`](https://github.com/upstash/context7/blob/main/packages/tools-ai-sdk/src/tools/query-docs.ts) | Exposes the `queryDocs` tool; handles missing docs and API errors. | <https://github.com/upstash/context7/blob/master/packages/tools-ai-sdk/src/tools/query-docs.ts> |
| [`packages/sdk/src/client.ts`](https://github.com/upstash/context7/blob/main/packages/sdk/src/client.ts) | High-level SDK entry point; validates API key and routes `getContext` calls. | <https://github.com/upstash/context7/blob/master/packages/sdk/src/client.ts> |
| [`packages/sdk/src/commands/get-context/index.ts`](https://github.com/upstash/context7/blob/main/packages/sdk/src/commands/get-context/index.ts) | Constructs the `/v2/context` API request; formats JSON vs. plain-text results. | <https://github.com/upstash/context7/blob/master/packages/sdk/src/commands/get-context/index.ts> |
| [`packages/mcp/src/lib/api.ts`](https://github.com/upstash/context7/blob/main/packages/mcp/src/lib/api.ts) | Low-level HTTP wrapper; performs fetch, parses errors, handles proxy config & rate-limit messages. | <https://github.com/upstash/context7/blob/master/packages/mcp/src/lib/api.ts> |
| [`packages/mcp/src/lib/constants.ts`](https://github.com/upstash/context7/blob/main/packages/mcp/src/lib/constants.ts) | Defines `CONTEXT7_API_BASE_URL` used by all API calls. | <https://github.com/upstash/context7/blob/master/packages/mcp/src/lib/constants.ts> |
| [`packages/sdk/src/http/index.ts`](https://github.com/upstash/context7/blob/main/packages/sdk/src/http/index.ts) | `HttpClient` implementation with retry & back-off strategy. | <https://github.com/upstash/context7/blob/master/packages/sdk/src/http/index.ts> |

These files together illustrate the full request lifecycle and are the primary places to investigate when documentation retrieval fails.

## Summary

- **Authentication failures** surface as 401 errors when `CONTEXT7_API_KEY` is missing, malformed, or revoked; verify the `ctx7sk` prefix and environment variable presence.
- **Library ID errors** occur when paths lack leading slashes or reference unsupported versions; use `resolveLibraryId` or `searchLibrary` to validate identifiers.
- **Empty results** indicate documentation hasn't been generated yet; switch to `type: "txt"` or retry after a delay.
- **Rate limiting** (429 errors) requires back-off periods or plan upgrades; the SDK's `HttpClient` provides automatic exponential retry.
- **Network issues** often involve proxy misconfiguration via `HTTPS_PROXY` variables; test direct connectivity to `https://context7.com/api`.
- **Debugging** requires inspecting the raw response at the MCP layer (`fetchLibraryContext`) when SDK error messages mask underlying issues.

## Frequently Asked Questions

### Why does Context7 return "Invalid API key" even when my key looks correct?

This error originates in [`packages/mcp/src/lib/api.ts`](https://github.com/upstash/context7/blob/main/packages/mcp/src/lib/api.ts) when the server returns a 401 status. The `Context7` constructor in [`packages/sdk/src/client.ts`](https://github.com/upstash/context7/blob/main/packages/sdk/src/client.ts) expects keys with the `ctx7sk` prefix. If your key lacks this prefix, was regenerated in the dashboard but not updated in your environment, or contains trailing whitespace, the authentication will fail. Verify the exact value with `echo "$CONTEXT7_API_KEY"` and ensure it matches the dashboard exactly.

### How do I fix "No documentation found for library" errors?

This message appears when the `libraryId` parameter doesn't match a processed library in the Context7 database. According to [`packages/sdk/src/commands/get-context/index.ts`](https://github.com/upstash/context7/blob/main/packages/sdk/src/commands/get-context/index.ts), the ID must be a valid path like `/facebook/react` or `/vercel/next.js/v14.3.0-canary.87`. Use the `resolveLibraryId` tool to automatically find the correct path, or call `client.searchLibrary()` to browse available libraries. Ensure you include the leading slash and match the case sensitivity exactly.

### What should I do when Context7 returns empty results for a valid library?

Empty responses indicate that while the library ID exists, Context7 hasn't finished processing the documentation yet. As implemented in [`packages/tools-ai-sdk/src/tools/query-docs.ts`](https://github.com/upstash/context7/blob/main/packages/tools-ai-sdk/src/tools/query-docs.ts), you can switch the request type from the default `json` to `txt` by setting `type: "txt"` in the options. This often retrieves raw documentation even when structured JSON isn't ready. If the issue persists, wait a few minutes and retry, as documentation generation is asynchronous for new library versions or private repositories.