Inspect the nested span hierarchy of an agent run to reveal execution shape and per-span durations. Provide a trace ID to see how steps nest and where time is spent.
Nested span tree of a run — the shape of what the agent did, with durations.
| Name | Required | Description | Default |
|---|---|---|---|
| trace_id | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.6.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are supplied, so the description carries the full behavioral burden, yet it discloses only that the result is nested and carries durations. It says nothing about read-only safety, whether trace_id must come from list_runs, output size for deep trees, or pagination/depth limits.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
One front-loaded sentence with no filler; the resource and the notable payload trait (durations) come first. It is efficient, though the brevity is partly under-specification rather than tight editing.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
An output schema exists, so return values need not be explained, but for a tool with no annotations the description leaves the agent without usage routing, the meaning/source of trace_id, or any scale caveat. It is thinner than a minimum-viable definition for a run-inspection tool with many siblings.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The single required parameter trace_id has 0% schema description coverage and is never mentioned in the description. With only one parameter the ambiguous origin of the value (which sibling produces a trace_id) is the key semantic gap, and it is left entirely unresolved.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description names a concrete resource and shape — a nested span tree of a run, including durations — which is more specific than a tautology and implicitly distinguishes it from flat siblings like search_spans and slowest_spans. It stops short of explicitly differentiating itself from run_summary or compare_runs.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
"The shape of what the agent did" gestures at a use case but gives no explicit when-to-use, when-not-to-use, or named alternative among the eleven siblings. An agent must infer whether this replaces or complements run_summary and search_spans.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.