Pain in the Agent MCP

Rewrite text through the free Pain in the Agent service from an AI client. The service returns revised prose and fidelity notes. The account allowance is 100 successful rewrites per month, shared with the web tool, with 100–10,000 characters per request.

I tested the underlying rewrite pipeline against the published SynthID Text reference implementation. The research and examples describe the test and its limits. This client cannot verify Claude or Gemini's private watermark keys, and it does not guarantee detector results.

Installation

First sign in and create an API key. Keep the key in your client's secret settings or environment, outside conversations and source control. You do not need an OpenRouter or OpenAI key.

Claude Desktop

Download the .mcpb file from the latest release, open it in Claude Desktop, and enter the service key in its API key setting. The MCPB bundle contains its Node dependencies. It uses Node.js 22 or later.

Codex

Clone this repository or extract a release. The committed dist/index.cjs is ready to run without npm install. Add this to your Codex MCP configuration, replacing the example absolute path with your checkout:

[mcp_servers.painintheagent]
command = "node"
args = ["/absolute/path/painintheagent-mcp/dist/index.cjs"]
env_vars = ["PAININTHEAGENT_API_KEY", "PAININTHEAGENT_BASE_URL"]
startup_timeout_sec = 15
tool_timeout_sec = 40

Set PAININTHEAGENT_API_KEY in the environment that starts Codex. Omit PAININTHEAGENT_BASE_URL for the public service. Restart the client after changing its environment.

A Codex plugin is also included at plugins/painintheagent-mcp/, with a repository marketplace at .agents/plugins/marketplace.json. To add this source, run codex plugin marketplace add krllagent/painintheagent-mcp and select Pain in the Agent from that source in the app. The generated catalog is named personal; it is a repository source, separate from OpenAI's public plugin directory. The plugin forwards the same two environment variables.

Claude Code

Set PAININTHEAGENT_API_KEY in the environment that starts Claude Code. Then use:

/plugin marketplace add krllagent/painintheagent-mcp
/plugin install painintheagent-mcp@painintheagent

The plugin includes a rewrite skill and the MCP server. A local checkout can also be loaded with claude --plugin-dir /absolute/path/painintheagent-mcp/claude-plugins/painintheagent-mcp.

Cursor and other local MCP clients

Configure a stdio server with command node and one argument, the absolute path to dist/index.cjs. Supply PAININTHEAGENT_API_KEY through your client's environment or secret setting. Clients have different environment-variable substitution syntax, so use the format your client documents. The MCPB and source release contain the same server.

Tools

Ask your agent to rewrite the draft through Pain in the Agent, preserve its claims and conditions, and show the fidelity notes. Keep the client open while it works; a rewrite can take several minutes. The local MCP process holds the service's streaming connection. Closing that process can interrupt the run. This version is a local stdio MCP server, not a remote HTTP MCP endpoint for ChatGPT.

Save the request ID. If the stream fails, use get_rewrite with that same ID to check for a saved result. The client never automatically retries a POST. Reusing an ID with identical input retrieves that run; different input with the same ID is rejected. Failed runs do not consume successful-run quota. In-flight requests reserve capacity. A lost run releases its reservation after an hour, while its old ID remains unavailable for a new run.

Privacy and gateways

Only supplied text is sent. This client does not read your files, save prose to disk, or emit telemetry. The hosted service sends prose to its model provider and stores source text and results as described in the privacy policy. Your MCP host may retain tool inputs and outputs under its own settings. Do not submit secrets or confidential personal data.

The client reads PAININTHEAGENT_API_KEY and optional PAININTHEAGENT_BASE_URL. The default base URL is https://painintheagent.com. A configured gateway receives every request; there is no credential or endpoint fallback. HTTP is accepted only for localhost gateways. Authentication uses a bearer header, and redirects are rejected.

Development

npm ci --ignore-scripts
npm run build
npm test
node scripts/package.mjs

The tests use fictional text and a local fake HTTP service. They cover endpoint selection, failed authentication, request reuse, dropped streams, and a fresh bundled installation speaking MCP over stdio. They do not call a paid model or claim to be live-provider validation.

See the API reference and distribution status. The client is MIT-licensed. The hosted service and research have their own terms and evidence.