# MCP Endpoint

> Markdown version of https://docs.postlake.dev/api/post-mcp . The canonical page for humans.
> PostLake is the social media API for AI agents: https://postlake.dev/llms.txt

`POST /v1/mcp`

Model Context Protocol JSON-RPC endpoint. PREFER `POST /mcp`: it is the canonical URL and now accepts either an API key or an OAuth access token, so there is no longer a reason to choose between two paths. This one is kept working for configs already pointing at it. The same tool registry covers publishing, scheduling, validation, media, notifications, comments, direct messages, engagement, profile and channel management, and analytics. See https://docs.postlake.dev/mcp for the full toolset and authentication options.

## Request

Authenticate with a bearer API key. Agents calling over MCP authorise with OAuth instead and never handle the key.

```bash
curl -X POST https://api.postlake.dev/v1/mcp \
  -H "Authorization: Bearer $POSTLAKE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"…","method":"…","params":{},"id":"…"}'
```

### Body

| Field | Type | Required | What it is |
| --- | --- | --- | --- |
| `jsonrpc` | string | Yes |  |
| `method` | string | Yes |  |
| `params` | object | No |  |
| `id` | string or number or null | No |  |


## Response

Success (`200`).

| Field | Type | Required | What it is |
| --- | --- | --- | --- |
| `jsonrpc` | string | Yes |  |
| `result` | object | No |  |
| `error` | object | No |  |
| `error.code` | integer | Yes |  |
| `error.message` | string | Yes |  |
| `error.data` | object | No |  |
| `id` | string or number or null | No |  |



### Example

```json
{
  "jsonrpc": "…",
  "result": {},
  "error": {
    "code": 0,
    "message": "…",
    "data": {}
  },
  "id": "…"
}
```


## Calling this from an agent

Agents working over the hosted MCP server reach the same product through tools rather than REST, and authorise with OAuth so your API key is never pasted into a chat.

## Errors

Every failure uses one shape: a stable `type`, a granular `code`, the field at fault in `param`, and a plain-language `fix`. See https://docs.postlake.dev/errors.md .

Check the result before retrying a write. Only operations that explicitly support idempotency can safely replay an `Idempotency-Key`.

## Common questions

**Is it safe to retry this call?**

Do not automatically repeat a write after a timeout unless that endpoint explicitly documents idempotency. First read the resulting state; a second request could repeat the action.

**What happens when it fails?**

You get one error shape: a stable type, a granular code you can branch on, the offending field in param, and a fix written so an agent can correct itself rather than stop. Full list on Errors and retries.