qa_compare_runs

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false. The description adds detailed behavioral context: categorization logic with priority ordering, that error responses start with 'Error:', and the return formats. No contradiction with annotations.

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?

Description is well-structured with bullet points and sections, each sentence adds value. It is concise yet comprehensive, front-loading the purpose and then detailing categories.

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 with moderate complexity (multi-category comparison), the description covers the full logic, return formats (Markdown/JSON), error handling, and even mentions what is not covered (flakiness). No output schema provided but the description explains what is returned.

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?

Schema description coverage is 100%, so baseline is 3. The description adds context for run_a and run_b as baseline/newer, reinforcing schema statements, and explains how the parameters drive the categorization logic, which adds meaning beyond the schema.

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 clearly states it compares two test runs and categorizes differences, listing all categories. It distinguishes itself from sibling tools (qa_get_run, qa_list_runs) by focusing on comparison rather than retrieval or listing.

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?

Explicitly explains that run_a is baseline (older) and run_b is newer, provides guidance on flakiness detection requiring N>2 runs and directs to an alternative (weekly_regression_review prompt). This covers when to use and when not to use.

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