The full upstream README, mirrored here for reference. Install config, tool schemas, adoption signals, and an original overview live on the Trace Forge listing page.
MCP server for writing structured traces, spans, and decisions. The only write-path observability MCP — all 9 existing observability MCPs are read-only.
Built for EU AI Act traceability compliance (Article 14, due August 2026).
Add to claude_desktop_config.json:
Begin a new trace for an agent task.
| Param | Type | Required | Description |
|---|---|---|---|
agent_id | string | yes | Unique agent identifier |
task_description | string | yes | What the agent is doing |
metadata | object | no | Optional metadata (model, department, priority) |
Returns: { trace_id, started_at }
Create a span within a trace. Spans can be nested via parent_span_id.
| Param | Type | Required | Description |
|---|---|---|---|
trace_id | string | yes | Trace to attach to |
span_name | string | yes | Span name (e.g. "research", "validation") |
parent_span_id | string | no | Parent span for nesting |
metadata | object | no | Optional span metadata |
Returns: { span_id, trace_id }
Log a tool call within a trace. Auto-calculates cost estimate from token count.
| Param | Type | Required | Description |
|---|---|---|---|
trace_id | string | yes | Trace this belongs to |
span_id | string | no | Span this belongs to |
tool_name | string | yes | Tool that was called |
args | object | yes | Arguments passed |
result_preview | string | yes | Result preview (max 500 chars) |
tokens_used | number | no | Token count (enables cost estimation) |
duration_ms | number | yes | Call duration in milliseconds |
status | string | yes | "success", "error", or "timeout" |
Returns: { event_id, logged: true }
Log an agent decision point with reasoning and alternatives considered.
| Param | Type | Required | Description |
|---|---|---|---|
trace_id | string | yes | Trace this belongs to |
reasoning | string | yes | Why the agent made this decision |
alternatives_considered | string[] | yes | Other options evaluated |
chosen_action | string | yes | What was decided |
confidence | number | yes | Confidence 0.0 to 1.0 |
Returns: { event_id, logged: true }
Complete a trace. Auto-calculates total duration, event counts, and span counts.
| Param | Type | Required | Description |
|---|---|---|---|
trace_id | string | yes | Trace to complete |
outcome | string | yes | "success", "failure", "partial", or "timeout" |
summary | string | no | Optional summary |
Returns: { trace_id, duration_ms, events_count, spans_count, tool_calls_count }
Retrieve a complete trace tree with all spans, events, tool calls, and decisions.
| Param | Type | Required | Description |
|---|---|---|---|
trace_id | string | yes | Trace ID to retrieve |
Returns: Full trace object with nested span tree, all events, and computed totals.
Find traces by agent ID and/or status.
| Param | Type | Default | Description |
|---|---|---|---|
agent_id | string | - | Filter by agent |
status | string | - | Filter by status |
limit | number | 20 | Max results (1-100) |
Returns: Matching traces sorted by recency with summary stats.
| URI | Description |
|---|---|
traces://recent | Last 20 traces with summary |
traces://stats | Aggregate statistics (total, avg duration, success rate) |
Article 14 of the EU AI Act requires high-risk AI systems to maintain traceability of decisions and actions. trace-forge-mcp provides:
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