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.
Authorization
[:anubis_mcp, :server, :authorization] is a :telemetry.span/3 wrapping
the Streamable HTTP bearer authorization flow, so it emits :start, :stop
and :exception events. See span_authorization/2. The :stop metadata
carries outcome, one of :ok, :missing_token, :invalid_token,
:invalid_issuer, :invalid_audience, :token_expired, :invalid_expiry,
:validator_unavailable, :other. Authorization metadata never includes
tokens, claims, or raw validator error reasons.
| Event | Metadata |
|---|---|
[:anubis_mcp, :server, :authorization, :start] | validator |
[:anubis_mcp, :server, :authorization, :stop] | validator, outcome |
[:anubis_mcp, :server, :authorization, :exception] | validator, kind, reason, stacktrace |
[:anubis_mcp, :server, :authorization, :validate] (deprecated) | validator |
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
Deprecated single-shot event emitted before the validator runs.
Execute a telemetry event with the Anubis MCP namespace.
Wraps a bearer authorization flow in the [:server, :authorization]
telemetry span.
Wraps a tool call handler invocation in the [:server, :tool_call]
telemetry span.
Functions
Deprecated single-shot event emitted before the validator runs.
Superseded by the [:server, :authorization] span: the :stop event's
bounded outcome reports whether validation succeeded and why it failed.
Kept during a deprecation window; attach handlers to the span instead.
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
@spec span_authorization(map(), (-> {result, Anubis.Server.Authorization.outcome()})) :: result when result: var
Wraps a bearer authorization flow in the [:server, :authorization]
telemetry span.
Emits :start, :stop and :exception events under
[:anubis_mcp, :server, :authorization]. The start_metadata map (typically
%{validator: module}) is used for the :start event and, with outcome
added, for the :stop event. The :stop measurements carry duration.
The fun returns {result, outcome} where outcome must be drawn from the
bounded set in Anubis.Server.Authorization.outcome/1. Tokens, claims, and
raw validator error reasons must not be added to the metadata.
Examples
Telemetry.span_authorization(%{validator: MyValidator}, fn ->
{{:ok, conn, claims}, :ok}
end)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