Sedata.AI Docs

When you call instrumentServer(server, config), the package patches server.registerTool so every subsequent tool you register runs inside an OpenTelemetry span.

Span shape

Each tool invocation produces a single span:

name:       tools/call <toolName>
status:     OK | ERROR
duration:   ms
attributes: { ... see below ... }

Attributes

Attribute	Description
`mcp.method.name`	Always `"tools/call"` for tool invocations.
`mcp.tool.name`	The tool name passed to `registerTool`.
`mcp.tool.title`	Tool title from the tool config.
`mcp.tool.description`	Tool description from the tool config.
`mcp.request.id`	UUID generated per request.
`mcp.session.id`	UUID generated when the SDK starts; constant for the process.
`mcp.operation.success`	`true` on OK, `false` on thrown error.
`mcp.operation.duration`	Duration in ms (also written as a histogram metric).
`client.address`	First non-internal IPv4 address of the host (`localhost` if none).
`client.port`	`process.env.PORT` if set.
`error.type`	Error class name (only on failure).
`error.message`	Error message (only on failure).

Optional attributes

These show up only under specific configurations:

Attribute	When
`mcp.request.argument.<key>`	When `enableArgumentCollection: true`. Each argument flattened into a span attribute.
`mcp.safety_check.content`	When the handler is wrapped with `safetyCheck`.
`mcp.safety_check.flagged`	`true` if Sedata’s safety API flagged the input.
`mcp.safety_check.latency_ms`	Round-trip latency of the safety check.
`mcp.safety_check.success`	`true` if the safety API responded successfully (whether flagged or not).

enableArgumentCollection is off by default. Tool arguments often contain user input, secrets, or PII — turn it on knowingly.

Resource attributes

The OTel resource attached to every span carries:

Key	Source
`service.name`	`config.serverName`
`service.version`	`config.serverVersion`
`mcp.session.id`	UUID per process
Host / OS / env detector attrs	From `@opentelemetry/resources` detectors

These are added once per process and merged into every export.

Errors

If your handler throws, the package:

Sets the span status to ERROR with the error message.
Sets error.type, error.message, mcp.operation.success: false.
Records the duration histogram with mcp.operation.success: false.
Re-throws the original error so the MCP runtime sees it.

span.name             tools/call calculate-bmi
status                ERROR
status.message        height cannot be zero
attributes.error.type RangeError

Sampling

By default, all spans are recorded (samplingRate: 1.0). To trim volume in production, set a ratio:

const config: TelemetryConfig = {
  // ...
  samplingRate: 0.1, // keep 10% of traces
}

The sampler is TraceIdRatioBasedSampler — head-based and deterministic per trace id. See Sampling for tradeoffs.

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Tracing

Span shape

Attributes

Optional attributes

Resource attributes

Errors

Sampling

What’s next

Automatic attributes reference

Custom spans

​Span shape

​Attributes

​Optional attributes

​Resource attributes

​Errors

​Sampling

​What’s next

Automatic attributes reference

Custom spans

Span shape

Attributes

Optional attributes

Resource attributes

Errors

Sampling

What’s next