perf_export_trace

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=true and openWorldHint=false, so the safety profile is covered; the description adds real value beyond that by naming the output path/filename pattern and disclosing a subtle caveat that a frame's GPU time can be shorter than its wall time when encoders run in parallel. It stops short of stating overwrite behavior for a pre-existing trace file, which would complete the picture.

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?

A single front-loaded sentence that opens with the action and artifact before descending into slice semantics. It is dense but nearly every clause carries information; the trailing phrase 'with the compute, fragment and vertex split as arguments' is the weakest and slightly ambiguous part.

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?

For a one-parameter tool with an output schema and full annotations, the description covers the output location, format compatibility, and the meaning of the trace contents. Only the runs-directory location and existing-file overwrite semantics are left unstated.

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?

There is only one parameter and schema description coverage is 100%, with the schema itself explaining that 'run' is 'a run name from perf_runs'. The description adds no further syntax or format detail, so the schema is doing all the work and baseline 3 applies.

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?

States a specific verb ('Writes') plus a precise resource ('a recording's GPU frames as a Chrome trace file') and names the exact artifact produced. An agent can immediately distinguish this file-producing export from sibling query tools like trace_query, trace_tables, and capture_summary.

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?

Usage is only implied: the mention that ui.perfetto.dev and chrome://tracing can open the output hints that this is for visual inspection, but the description never says when to prefer this over trace_query or capture_summary, nor when not to use it. No prerequisites (e.g. that a run must already be recorded) are stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.