# MCP FAQ

> Answers to the common questions about the Harny MCP server, its keys, and its costs.

## Keys and sign-in

### Is there OAuth?
Yes, for a coding assistant. The app's owner signs in on the Harny console, picks or creates the app and approves a coding assistant. The assistant then holds a token that lasts an hour and renews, instead of a copied key. Its address is not published yet, so connect with a key until it is. Keys work as before: send your key in the `Authorization: Bearer <key>` header. Connecting a person's own accounts is a separate step: `configure_oauth`.

### Which key do I use?
Use the app key (starts with `fsa_`) for app-level tools such as `provision_user`, `get_claim_link` and `get_setup_bundle`. Use a person's key (starts with `fsk_`) for tools such as `ingest_text`, `assemble_context`, `list_tools`, `configure_oauth` and `action_history`. `describe`, `get_snippet` and `diagnose` accept any key. See [Quickstart](/docs/mcp/quickstart) for setup and [Keys and access](/docs/mcp/keys-and-access) for more.

### Can the model choose the user?
No. Calls are scoped to the key's user. A person's key reaches only that person's memory and actions. See [Tools](/docs/mcp/tools) for the full list.

## Clients

### Does it work with Claude Code and Cursor?
Yes. Claude Code and Cursor both connect over Streamable HTTP at `https://api.harny.ai/v1/mcp/mcp`. See [Quickstart](/docs/mcp/quickstart) for the exact config.

### Does it work with Replit?
Owner to confirm. This page does not list Replit as a supported client.

## Behavior

### What happens with no key?
The server offers only `provision_app`. Every other tool needs a key.

### Can I use provision_app from a coding agent?
A coding agent that can run commands should follow https://harny.ai/auth.md instead. Its command never shows the key.

### What happens over the rate limit?
The call answers 429 with Retry-After. MCP calls follow the same limits and refusals as the REST routes they wrap. See [Limits](/docs/mcp/limits).

### Can the server search the web?
No. The server exposes only the tools listed on the [Tools](/docs/mcp/tools) page, and none of them search the web.

## Data and cost

### How do I erase a person?
Call `DELETE /v1/users/{user_id}/data`. See the [Memory API](/docs/memory-api/overview) docs for details.

### Does it cost anything extra?
The first 500 monthly-active end users are free. A monthly-active end user is a person with at least one memory read, one memory write or one recorded agent action in a calendar month. Stored but dormant users are free. Above 500, the price is $0.30 per monthly-active end user per month, flat.

### Where is the REST API?
The MCP tools wrap REST routes. `ingest_text` and `assemble_context` wrap `POST /v1/vault/ingest/text` and `POST /v1/context/assemble`. The Memory API lives at `https://api.harny.ai/v1/memory`. See the [Memory API](/docs/memory-api/overview) docs.

## Next

- [Quickstart](/docs/mcp/quickstart)
- [Tools](/docs/mcp/tools)
- [Memory API](/docs/memory-api/overview)