upload - Murmur

Uploads a file from the agent’s local disk to the public storage bucket. Returns the public HTTPS URL. Useful for attaching screenshots, diagrams, or build artifacts to PR descriptions and comments. Equivalent to murmur upload in the CLI. This tool is available only on the local murmur mcp server. The hosted MCP endpoint does not expose it.

Parameters

Name	Type	Required	Description
`filename`	string	yes	File name (e.g. `diagram.png`). Names the uploaded file and infers the MIME type when `content_type` is omitted. It does not have to match the file name in `path`.
`path`	string	yes	Absolute path to the file on disk.
`content_type`	string	no	MIME type (e.g. `image/png`). Inferred from `filename` extension if omitted. Falls back to `application/octet-stream`.
`workspace`	string	no	Workspace name. Overrides the session default.

Response

Returns the public HTTPS URL as a plain string. Every upload gets a fresh URL, even for the same file.

Examples

Upload a screenshot

{
  "filename": "screenshot.png",
  "path": "/tmp/screenshot.png"
}

Response:

https://murmur-uploads.storage.googleapis.com/t/github_app/acme/uploads/github_app/acme/w/backend/github_oauth/alice/fix-auth/3f2b9c1e-5d7a-4e8b-9c0d-1a2b3c4d5e6f-screenshot.png

Upload with explicit MIME type

{
  "filename": "report.html",
  "path": "/home/agent/output/report.html",
  "content_type": "text/html"
}

Errors

Code	Meaning	What to do
none	`open <path>: ...`: the file at `path` cannot be read.	Check that the file exists on disk and is readable.
`UNAUTHENTICATED`	Identity token is missing or expired.	Check credentials.

murmur upload: equivalent CLI command
port_url: share a live service URL instead of a static file
murmur timeline: list an agent’s timeline, including upload events