---
title: "context7 setup: official plugin + API key"
type: concept
updated: 2026-04-28
---

# context7 setup: official plugin + API key

_2026-04-28._

## Where the MCP server is now registered

Single source: the official plugin **`context7@claude-plugins-official`**.

The plugin's `.mcp.json` (after install) lives at:
```
~/.claude/plugins/cache/claude-plugins-official/context7/<version>/.mcp.json
```

For this user the version slug is `unknown` (marketplace plugin without a tagged release).

## API-key injection

The `@upstash/context7-mcp` npm package, run via stdio, accepts the key as a CLI flag (per Upstash docs at <https://context7.com/docs/resources/all-clients>):

```json
{
  "context7": {
    "command": "npx",
    "args": ["-y", "@upstash/context7-mcp", "--api-key", "ctx7sk-..."]
  }
}
```

We injected the user's existing key (previously in HTTP-header form) into this `args` array. Header / `env` block forms are also supported, but the CLI flag is what Upstash recommends for stdio.

## What was removed

Three manual MCP registrations were deleted:

| File | Where | Had API key? |
|---|---|---|
| `~/.claude/settings.json` | top-level `mcpServers.context7` | yes (header) |
| `~/.claude.json` | top-level `mcpServers.context7` | yes (header) |
| `~/.claude.json` | `projects["…/snolla-admin-ui"].mcpServers.context7` | no (legacy) |

Backups saved with suffix `.bak-YYYYMMDD-HHMMSS` next to each file.

## ⚠️ Plugin-update gotcha

`/plugin update context7@claude-plugins-official` (or a fresh re-install) **will overwrite** the plugin's `.mcp.json` from the marketplace cache, dropping the `--api-key` flag. After any plugin update, re-apply the edit:

```bash
# inspect
cat ~/.claude/plugins/cache/claude-plugins-official/context7/<version>/.mcp.json

# if --api-key is missing, re-inject
```

The marketplace upstream of the plugin lives at `anthropics/claude-plugins-official/external_plugins/context7/.mcp.json` and is two lines — unlikely to change often, but we should expect to re-apply the flag after updates.

## Restart required to take effect

Claude Code reads MCP server configs at session start. The session in which this change was made keeps its old (HTTP-transport) connection until a restart. After restart, the plugin's stdio invocation takes over.

## Why this matters

Manual MCP entries in `~/.claude.json` / `settings.json` are easy to:
- duplicate accidentally (we had three for one server)
- forget about when sharing config
- drift from the canonical version

The plugin centralizes the registration and gets versioned through the marketplace. The price is a single edit-after-update for the API key.

## Now captured as a skill

The procedure above is now formalized as the **`setup-context7`** skill ([`skills/setup-context7/SKILL.md`](../../skills/setup-context7/SKILL.md)). It runs the same algorithm with confirmation gates and key-discovery logic (search `settings.json` → `.claude.json` → env, reuse what's there, never invent). `using-context7` got a small **Prerequisites** section pointing at it.

### Why split into two skills

Two distinct concerns:

- **Policy** (every-time, short-running): when to call resolve-library-id, query budget, how to phrase queries — this lives in `using-context7`.
- **Setup** (one-time, mutates user config): install plugin, inject key, clean manual entries — this lives in `setup-context7`.

Mixing them would make the policy skill ~2× larger, dilute its description (worse triggering), and make every library question pull setup procedure into context. The split is also a template for future "X plugin + how-to-use-X" skill pairs.

### Cross-platform

The setup skill is platform-agnostic. Only the JSON validator differs (PowerShell on Windows, `jq` / Python on Linux/macOS). Paths (`~/.claude/...`) are identical.