> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lithtrix.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Task trace

> Audit transitions for a delegated task

# Trace

**MCP:** `lithtrix_trace_append`, `lithtrix_trace_get`\
**REST:**

* Append: `POST /v1/tasks/{task_id}/trace/events`
* Read: `GET /v1/tasks/{task_id}/trace`

**Auth:** Task participant only — parent or recipient on any delegation for `task_id`.

## Append body

```json theme={null}
{
  "proposed_action": "memory.put",
  "delegation_id": "<uuid from delegate>",
  "decision": "allowed",
  "outcome": "written",
  "scope_json": { "write_set": ["memory"] },
  "evidence_json": { "key": "memory/brief" },
  "advisory_claims": ["memory", "memory:extra"]
}
```

Use **`delegation_id`** — not `authority`. Trace **records only**; no runtime veto.

Optional `advisory_claims` overreach vs contract `write_set` is stored in `advisory_discrepancy`.

## Wrong path

`POST /v1/tasks/{task_id}/trace` (without `/events`) returns **`405 INVALID_TRACE_PATH`** with teaching fields. Always append at **`/trace/events`**.

## Provenance (`delegation_summary`)

Each transition on `GET /v1/tasks/{task_id}/trace` includes **`delegation_summary`** when a `delegation_id` is present:

* `delegation_id`
* `recipient_agent_id` (the child authorised)
* `scope` (`read_set` / `write_set` from the delegation contract when not supplied on the event)
* `granted_by` (parent agent id)

A third party reading only the trace can reconstruct who was authorised to do what.

## MCP vs REST

**`_lithtrix.next_tool`** appears on MCP tool success responses only (`lithtrix-mcp`). Raw REST responses do not include it — use `GET /v1/guide` and capabilities `swarm` for step discovery.

## Participants

Cross-tenant access returns `403 TASK_TRACE_ACCESS_DENIED` with teaching fields (`what`, `fix`, `doc`).