Anubis.
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Telemetry events emitted by Anubis.
Every event is namespaced under [:anubis_mcp | event]. The client emits
them, the server emits them, and the transports emit their own.
Attaching handlers
:telemetry.attach_many(
"anubis-metrics",
[
[:anubis_mcp, :server, :request],
[:anubis_mcp, :server, :tool_call, :stop]
],
&MyApp.Metrics.handle_event/4,
%{}
)Events
Most events carry %{system_time: System.system_time()} as their only
measurement; the interesting payload is in the metadata. The
:response and :error events also carry %{duration: elapsed_ms}.
Client
| Event | Metadata |
|---|---|
[:anubis_mcp, :client, :init] | client_name, transport, protocol_version, capabilities |
[:anubis_mcp, :client, :request] | method, request_id |
[:anubis_mcp, :client, :response] | id, method, status, transport |
[:anubis_mcp, :client, :notification] | method, uri |
[:anubis_mcp, :client, :error] | id, method, error |
[:anubis_mcp, :client, :terminate] | client_name, reason, pending_requests |
[:anubis_mcp, :client, :roots] | action, request_id |
Server
| Event | Metadata |
|---|---|
[:anubis_mcp, :server, :init] | session_id, capabilities, server_info, module |
[:anubis_mcp, :server, :request] | id |
[:anubis_mcp, :server, :response] | id, method, level |
[:anubis_mcp, :server, :notification] | method, server_module, started_at |
[:anubis_mcp, :server, :error] | id, error, message, session_id, stateless |
[:anubis_mcp, :server, :terminate] | reason |
Tool calls
[:anubis_mcp, :server, :tool_call] is a :telemetry.span/3, so it emits
:start, :stop and :exception events. See span_tool_call/3.
Transport
Transport events always carry transport (the layer, e.g. :stdio or
:streamable_http). The rest varies by transport:
| Event | Metadata |
|---|---|
[:anubis_mcp, :transport, :init] | transport, client, io_device |
[:anubis_mcp, :transport, :connect] | transport, client |
[:anubis_mcp, :transport, :send] | transport, client |
[:anubis_mcp, :transport, :receive] | transport, client, message_size |
[:anubis_mcp, :transport, :disconnect] | transport, client, reason |
[:anubis_mcp, :transport, :terminate] | transport, client, reason |
[:anubis_mcp, :transport, :error] | transport, client, error |
[:anubis_mcp, :transport, :sse_handler, :registered] | session_id, handler_pid, handler_count (measurement) |
Treat metadata as open: new keys may be added, so match on the ones you need and ignore the rest.
Summary
Functions
Execute a telemetry event with the Anubis MCP namespace.
Wraps a tool call handler invocation in the [:server, :tool_call]
telemetry span.
Functions
Execute a telemetry event with the Anubis MCP namespace.
Parameters
event_name- List of atoms for the event name, excluding the :anubis_mcp prefixmeasurements- Map of measurements for the eventmetadata- Map of metadata for the event
Wraps a tool call handler invocation in the [:server, :tool_call]
telemetry span.
Shared by the synchronous scheduler dispatch and the task-augmented
tools/call worker path so both surface identical span data regardless
of which route a given request took.
The span's :start metadata always carries tool; the :stop metadata
always carries tool and is_error. When
:telemetry_capture_tool_payload is enabled (defaults to false), the
:start metadata also carries arguments and the :stop metadata also
carries result. See pages/testing.md for the rationale behind the
opt-in default.
Examples
iex> Anubis.Telemetry.span_tool_call("get_weather", %{"city" => "NYC"}, fn -> :ok end)
:ok