trim_trace_archive

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

The description transparently says it deletes screenshots and returns sizes/path, but it does not explicitly state whether the original trace file is preserved. The divergence_only parameter's false behavior (leaving screenshots intact) is explained but raises ambiguity about what the tool actually produces in that mode. Without annotations, this leaves moderate behavioral uncertainty.

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?

The description is two sentences, front-loaded with the verb 'Shrinks', and contains no fluff. It efficiently communicates the deletion criterion and the return value, making every sentence earn its place.

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 tool that modifies a trace archive, the description is fairly complete but leaves notable gaps: it doesn't explicitly state that the original file is preserved, doesn't explain behavior when no failure exists, and doesn't resolve the divergence_only=false output behavior. With no annotations or output schema, these gaps are more significant than they would be otherwise.

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 input schema already provides thorough descriptions for both parameters (100% coverage). The tool description adds the specific failure window (t_fail - 5s to t_fail + 1s) and mentions the output format, providing some context. However, it does not fully clarify the behavior when divergence_only is false, leaving ambiguity about what is returned in that case.

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 uses a specific verb (Shrinks) with a clear resource (Playwright trace zip file) and specifies the exact deletion criterion (screenshots outside the critical failure window t_fail - 5s to t_fail + 1s). It also states the output (original vs trimmed size and path to the new archive). This differentiates it from the sibling tools, which are all read-only analysis tools.

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 description implies the tool is used to reduce trace size by keeping only the critical failure window, but it does not explicitly contrast with sibling tools or state when not to use it (e.g., if the complete trace is needed). While no sibling tool performs trimming, the lack of explicit alternative guidance leaves the usage context only implied.

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