Limits & errors

Rate limits

Scope	Limit
MCP requests per OAuth access token	1,000 per hour
MCP requests per API key	1,000 per hour
Dynamic Client Registration	10 per hour per IP address
Authorization code exchange	20 per hour per client and IP address
Token refresh	60 per hour per client
All requests from one IP address	2,000 per minute

When a limit is reached, the server responds with HTTP 429 and a body that says how long to wait:

{
  "error": "rate_limit_exceeded",
  "error_description": "Too many requests",
  "retry_after": 1200
}

retry_after is in seconds. Requests authenticated with an API key return {"error": "Rate limit exceeded", "retryAfter": 1200, "remaining": 0} instead, and the per-IP limit returns {"msg": "…", "retryAfterSeconds": 30, …}. Wait the indicated time before retrying.

Credits

Evermuse MCP access is included with your Evermuse workspace and is metered in Evermuse Credits:

Each successful tool call uses 1 credit.
find_skills and read_skills are free.
Calls that fail aren’t charged.
Sources you add with add_source also use credits when Evermuse processes them, the same as uploads in the app. Re-submitting a meeting or communication that already exists isn’t processed again.

New workspaces include free credits so you can try Evermuse. Workspaces on a paid plan keep working past their included credits and are billed for additional usage under their plan. Your workspace’s credit usage is shown in the Evermuse app. If a workspace without an active plan runs out of credits, tools return this error (skills tools keep working):

Error: MCP access is paused: this workspace has no Evermuse Credits remaining and no active plan.

Size limits

Limit	Value
Request body	75 MB (to allow base64-encoded files)
File upload through `add_source`	About 50 MB before base64 encoding
Transcript or message text per `add_source` call	4 MB
Results per page, search-shaped tools (with guidance)	About 30,000 characters of items, plus guidance
Results per page, search-shaped tools (without guidance)	About 80,000 characters
`read_source` page	Up to 500 segments or about 60,000 characters
Items per `add_signals` or `update_signals` call	100

When a page is trimmed to fit, the result reports next_offset. Call the tool again with offset set to that value to continue.

Protocol details

Property	Value
Endpoint	`POST https://api.evermuse.com/api/mcp`
Transport	Streamable HTTP, stateless. Each request is independent, and responses are JSON (no SSE stream).
Protocol versions	`2025-11-25`, `2025-06-18`, `2025-03-26`, `2024-11-05`, `2024-10-07`
Required headers	`Content-Type: application/json` and `Accept: application/json, text/event-stream`
Sessions	None. The server doesn’t issue an `Mcp-Session-Id`, and each request is independent.
Server features	Tools and prompts. Resources (MCP Apps UI) only for early-access tools.
Not supported	`GET` (SSE streams) and `DELETE` (session termination) return `405`. Server-initiated requests such as sampling and elicitation aren’t used.

HTTP errors

Status	When	Body
`400`	Malformed JSON-RPC, or an unsupported `MCP-Protocol-Version`.	JSON-RPC error
`401`	No credentials. Includes `WWW-Authenticate: Bearer resource_metadata="…"`.	`{"error":"Unauthorized","error_description":"Authentication required. …"}`
`401`	Invalid, expired or revoked access token, or the user no longer belongs to the workspace.	`{"error":"invalid_token","error_description":"Access token expired"}` (or a similar description)
`401`	Missing or invalid API key.	`{"error":"Invalid API key"}`
`403`	API key without MCP permissions.	`{"error":"API key does not have mcp permissions"}`
`405`	`GET` or `DELETE` on the MCP endpoint.	JSON-RPC error `-32000`
`406`	`Accept` header missing `application/json` or `text/event-stream`.	JSON-RPC error
`413`	Request body larger than 75 MB.	Error response
`415`	`Content-Type` isn’t `application/json`.	JSON-RPC error
`429`	Rate limit exceeded.	See Rate limits
`500`	Unexpected server error.	JSON-RPC error `-32603`

On a 401 with invalid_token, clients should refresh the access token and retry once. If the refresh fails, sign in again.

Tool errors

Problems with a specific tool call are returned as a normal MCP result with isError: true and a message the agent can act on, rather than an HTTP error. Common examples:

Message	Meaning and fix
`product_id is required. Call get_products …`	The tool needs a product. Call `get_products` and pass a `product_id`.
`Product not found: "…" is not a product in this workspace. …`	The id is wrong or belongs to another workspace.
`Project not found or access denied`	The `project_id` isn’t a project in this workspace.
`Source not found or access denied`	The source id is wrong or outside your workspace.
`This source has no content yet (still processing?)`	The source was added recently. Try again later.
`… does not exist or you are not allowed to access it`	`view_item` couldn’t find the item. Check `item_id` and `item_type`.
`Tool "…" is not available on this connection.`	The tool needs a scope the connection doesn’t have, such as `mcp:write` for signal writes. Reconnect to grant it.
`Tool "…" is not available for this workspace.`	The workspace stores its data locally (Evermuse Desktop). See Troubleshooting.
`MCP access is paused: …`	The workspace is out of credits. See Credits.
`Unknown signal type "…"`	`add_signals` received a type that isn’t active in your workspace.

Removed or renamed tools return a message explaining the change, naming a replacement where one exists. For example, see_updated_roadmap points to get_opportunities.

Get Started

Reference

Trust & Support

Rate limits

Credits

Size limits

Protocol details

HTTP errors

Tool errors

​Rate limits

​Credits

​Size limits

​Protocol details

​HTTP errors

​Tool errors

Rate limits

Credits

Size limits

Protocol details

HTTP errors

Tool errors