# Hookline MCP

> Lets your agent create test webhook endpoints, read the requests that arrive and validate payloads in your Hookline workspace.

Hookline MCP connects your agent to Hookline, a tool for inspecting, mocking and validating webhooks and API payloads. Your agent can run the whole loop without leaving the editor: create an endpoint, wait for a request, validate the payload, read the findings and adjust the mock response.

What you can do with it
- Create test webhook endpoints, optionally set to expire, and get the URL to send requests to
- Wait for the next request after a send, and read requests with their headers, query strings and bodies
- Validate payloads against your Hookline validators, which cover built-in specs such as OpenRTB, CloudEvents and Standard Webhooks, or your own JSON Schema
- Compare two payloads, search rules and read validation history
- Write custom rules by field path, create validators and set an endpoint's mock response
- Make a read-only, expiring share link to a single received request

How it connects
It runs on your machine with npx -y @hookline/mcp and needs Node 20 or later. It takes a Hookline agent key (hlk_...) in HOOKLINE_API_KEY, which you create at app.hookline.org/settings/mcp. Hookline has a free plan for one workspace.

Read-only by default
Hookline recommends the read-only key preset as the safe default. With a read-only key the write tools aren't registered at all, so your agent never sees them. Creating endpoints, validators, rules, share links and mock responses needs a key with write access.

Good to know
Webhook bodies come from outside senders, so the server marks them as untrusted data. Hookline says plainly that this lowers the risk of prompt injection but doesn't remove it. Treat mock response bodies as public: anyone who knows an endpoint's URL can read them.

- Type: Plugin
- Made by: Hookline
- Category: Automation
- Formats: Local MCP
- Version: 0.9.1
- Website: https://hookline.org
- Source: https://github.com/hookline-org/mcp
- Page: https://pluginboard.ai/plugins/hookline-mcp

## Works with

- Claude
- GitHub Copilot
- Cursor
- Claude Code
- Codex
- Antigravity
- Gemini CLI
- OpenClaw
- OpenCode
- Hermes Agent

## Install

You'll need:

- `HOOKLINE_API_KEY` (required): Hookline agent API key (hlk_...) from https://app.hookline.org/settings/mcp

Replace each `<NAME>` placeholder with your own value.

### Claude

Add to claude_desktop_config.json:

```json
{
  "mcpServers": {
    "hookline-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@hookline/mcp@0.9.1"
      ],
      "env": {
        "HOOKLINE_API_KEY": "<HOOKLINE_API_KEY>"
      }
    }
  }
}
```

### GitHub Copilot

Add to VS Code: vscode:mcp/install?%7B%22name%22%3A%22hookline-mcp%22%2C%22command%22%3A%22npx%22%2C%22args%22%3A%5B%22-y%22%2C%22%40hookline%2Fmcp%400.9.1%22%5D%2C%22env%22%3A%7B%22HOOKLINE_API_KEY%22%3A%22%3CHOOKLINE_API_KEY%3E%22%7D%7D

Run in your terminal:

```shell
code --add-mcp '{"name":"hookline-mcp","command":"npx","args":["-y","@hookline/mcp@0.9.1"],"env":{"HOOKLINE_API_KEY":"<HOOKLINE_API_KEY>"}}'
```

Copilot CLI:

```shell
copilot mcp add hookline-mcp --env HOOKLINE_API_KEY=<HOOKLINE_API_KEY> -- npx -y @hookline/mcp@0.9.1
```

### Cursor

Add to Cursor: cursor://anysphere.cursor-deeplink/mcp/install?name=hookline-mcp&config=eyJjb21tYW5kIjoibnB4IiwiYXJncyI6WyIteSIsIkBob29rbGluZS9tY3BAMC45LjEiXSwiZW52Ijp7IkhPT0tMSU5FX0FQSV9LRVkiOiI8SE9PS0xJTkVfQVBJX0tFWT4ifX0%3D

Add to .cursor/mcp.json:

```json
{
  "mcpServers": {
    "hookline-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@hookline/mcp@0.9.1"
      ],
      "env": {
        "HOOKLINE_API_KEY": "<HOOKLINE_API_KEY>"
      }
    }
  }
}
```

### Claude Code

Run in your terminal:

```shell
claude mcp add -e HOOKLINE_API_KEY=<HOOKLINE_API_KEY> hookline-mcp -- npx -y @hookline/mcp@0.9.1
```

### Codex

Run in your terminal:

```shell
codex mcp add --env HOOKLINE_API_KEY=<HOOKLINE_API_KEY> hookline-mcp -- npx -y @hookline/mcp@0.9.1
```

### Antigravity

Add to ~/.gemini/config/mcp_config.json:

```json
{
  "mcpServers": {
    "hookline-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@hookline/mcp@0.9.1"
      ],
      "env": {
        "HOOKLINE_API_KEY": "<HOOKLINE_API_KEY>"
      }
    }
  }
}
```

### Gemini CLI

Run in your terminal:

```shell
gemini mcp add -e HOOKLINE_API_KEY=<HOOKLINE_API_KEY> hookline-mcp npx -y @hookline/mcp@0.9.1
```

### OpenClaw

In a terminal: Run openclaw mcp add hookline-mcp --command npx, with --arg before each argument (-y @hookline/mcp@0.9.1) and --env NAME=value for each variable it needs.

### OpenCode

Run in your terminal:

```shell
opencode mcp add hookline-mcp --env HOOKLINE_API_KEY=<HOOKLINE_API_KEY> -- npx -y @hookline/mcp@0.9.1
```

### Hermes Agent

Add to ~/.hermes/config.yaml:

```json
{
  "mcp_servers": {
    "hookline-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@hookline/mcp@0.9.1"
      ],
      "env": {
        "HOOKLINE_API_KEY": "<HOOKLINE_API_KEY>"
      }
    }
  }
}
```

---
From Pluginboard (https://pluginboard.ai).