> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tierzero.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Claude Code

> Install the TierZero plugin in Claude Code and authenticate via OAuth.

The TierZero plugin for Claude Code wraps the [MCP server](/references/mcp/overview) with a `/tierzero` slash command and a skill that auto-loads when production context would help. Authentication is OAuth — there's nothing to copy or paste.

## Install

1. Add the TierZero marketplace:

```
/plugin marketplace add TierZeroAI/tierzero-claude-code
```

2. Install the plugin:

```
/plugin install tierzero@tierzero
```

3. Run any `/tierzero` command. The first time, Claude Code prompts you to authenticate — run `/mcp` and approve the connection in your browser.

```
/tierzero What errors occurred in payment-service in the last hour?
```

<img src="https://mintcdn.com/tierzeroaiinc/lsN3tRY4LzBSS3sM/images/mcp-claude-code-tierzero.webp?fit=max&auto=format&n=lsN3tRY4LzBSS3sM&q=85&s=605a7d102862569968b2f482e77ba783" alt="Claude Code authenticating the TierZero MCP server and fetching an investigation" className="rounded-lg shadow-lg my-6 border border-gray-800" width="1372" height="988" data-path="images/mcp-claude-code-tierzero.webp" />

## Project-wide installation

To enable the TierZero plugin for your whole team, add this to your project's `.claude/settings.json` and commit it:

```json theme={null}
{
  "extraKnownMarketplaces": {
    "tierzero": {
      "source": {
        "source": "github",
        "repo": "TierZeroAI/tierzero-claude-code"
      }
    }
  },
  "enabledPlugins": {
    "tierzero@tierzero": true
  }
}
```

Anyone who clones the project will have the plugin available; each user authenticates individually on first use.

## Usage

With the plugin installed, Claude Code automatically loads the `tierzero` skill when your task would benefit from production context — it can query TierZero in the background while it continues working on your code.

You can also explicitly start an investigation:

```text theme={null}
/tierzero What errors occurred in payment-service in the last hour?
```

Or pull existing context from a TierZero chat, investigation, or digest:

```text theme={null}
/tierzero:fetch-context https://app.tierzero.ai/chat/c/<GlobalID>
```

See the [overview](/references/mcp/overview) for a full description of `tierzero_ask` and `tierzero_fetch_context`.