Feature request: built-in MCP endpoint for sending messages from AI agents #1059

Is your feature request related to a problem? Please describe.

AI coding agents and assistants (Claude Code, VS Code Copilot, Cherry Studio, n8n, …) increasingly run long tasks unattended, and a common need is "notify me on my phone when you're done or need input". These tools speak the Model Context Protocol (MCP). Today, connecting them to Gotify requires either writing a custom script per agent or running a separate local MCP bridge process (e.g. taigrr/gotify-mcp, stdio only) on every machine the agent runs on. That doesn't work for remote/hosted agents that can only reach an HTTP URL.

Describe the solution you'd like

An optional, built-in MCP endpoint at /mcp that lets an agent send a message using an application token, so setup is a single line:

claude mcp add gotify --transport http https://gotify.example.com/mcp --header "Authorization: Bearer <apptoken>"

Bark ships a similar built-in endpoint.

I have a working implementation at RedwindA/server@feat/mcp and I'm happy to open a PR if you're open to the idea. Scope was deliberately kept minimal:

• Auth: only application tokens, via the existing RequireApplicationToken middleware (header, Authorization: Bearer, or ?token= query, which is already masked in the access log). Client tokens and basic auth are rejected, so an agent can never read or delete messages or manage anything.
• One tool: send_message with message (required), title, priority, and three convenience flags mapped to the documented extras: markdown → client::display.contentType, click_url → client::notification.click.url, big_image_url → client::notification.bigImageUrl. Raw extras are intentionally not exposed, to keep LLMs from making up namespaces.
• Stateless: Streamable HTTP in stateless + JSON-response mode. No sessions, no SSE, no long-lived connections, no extra state in the server. It behaves like any other REST endpoint behind a reverse proxy or with multiple instances.
• Code reuse: the defaulting/store/notify logic of CreateMessage is extracted into a shared helper, so REST and MCP behave the same (default title = app name, default priority, stream notification).
• Opt-out: GOTIFY_SERVER_MCP_ENABLED (default true; false means /mcp is not registered at all).
• Size: ~115 lines in api/mcp.go, a small refactor in api/message.go, config/router wiring, integration tests using the SDK client, and a README section.
• Dependency: the official github.com/modelcontextprotocol/go-sdk (v1.x, maintained by the MCP org together with Google). It adds 5 small indirect modules (google/jsonschema-go, segmentio/encoding, segmentio/asm, yosida95/uritemplate, golang.org/x/time).

Describe alternatives you've considered

• External bridge / contrib project (like taigrr/gotify-mcp): works for local stdio use, but every agent host needs an extra binary and config, and it can't serve remote agents that only accept an HTTP URL.
• Plugin: a plugin could host an HTTP endpoint under /plugin/:id/custom/…, but it would send as the plugin's own internal application rather than the user's existing apps, and it wouldn't reuse the normal token auth. Once the new IPC plugin system ([RFC] A plugin system that does not rely on Go plugin/dynamic linker #825) lands, this could be revisited, but it would still be less discoverable than a built-in endpoint.
• Plain REST: agents can be told to curl /message, but that needs shell access, per-agent prompting, and exposes the token in the agent's command history. MCP tools are discovered automatically and the token stays in the client config.

Additional context

I understand if you'd rather keep this out of core. In that case I'd be glad to turn it into a standalone HTTP service and submit it to gotify/contrib instead. Feedback on the tool shape (names/parameters) is welcome either way.