MCP server that turns PowForge pow-captcha into agent auth. Charge AI agents per-call without accounts: PoW solve = free tier, Lightning payment =
Most payments and commerce work still happens through a UI a human drives. Captcha MCP MCP server moves it into the conversation instead. MCP server that turns PowForge pow-captcha into agent auth. Charge AI agents per-call without accounts: PoW solve = free tier, Lightning payment = paid tier. Three tools: challenge, verify, status. Stdio + HTTP Streamable transports.
OpenAI's Sora API does not let you charge per call. Anthropic's billing does not pass through to your tools. If you ship an MCP server today and an autonomous agent finds it, you eat the bill.
The server publishes 2 tools. What each one is for:
Approach — Per-call costOAuth — $0Because this one is hosted, setup is mostly authentication — you point your client at the endpoint and approve access. Nothing runs on your machine, so there is no runtime to keep patched.
Configuration is passed through the environment: CAPTCHA_URL. Treat anything key-shaped as a real credential — scope it to the minimum the server needs, and rotate it if it ever lands in a shared config.
This sits in the payments and commerce group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. Captcha MCP's toolset — Approach, OAuth — is a fair guide to whether it matches your workflow. It is maintained by zekebuilds-lab; worth a glance at recent repository activity before you build anything load-bearing on it.
We check each listing at SyncDev against the project's documentation before it goes live — if something here drifts out of date, it is a bug worth reporting.
| Tool | What it does |
|---|---|
| Approach | Per-call cost |
| OAuth | $0 |
{
"mcpServers": {
"captcha": {
"command": "npx",
"args": ["-y", "@powforge/captcha-mcp"],
"env": {
"CAPTCHA_URL": "your-value"
}
}
}
}Add to claude_desktop_config.json, then restart Claude Desktop.
| Variable | Description | Required |
|---|---|---|
| CAPTCHA_URL | Endpoint or connection string the server talks to. | Yes |
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