compare_periods

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

With no annotations the description carries the burden, and it does add real behavioral context: the result is side-by-side metrics with deltas, it also lists agents/maps per block, and it warns to check win_pct confidence ranges before treating a change as real. It omits failure/edge behavior (e.g. insufficient history), which keeps it from a 5.

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?

Four short sentences, front-loaded with the core comparison, then usage, then an output hint, then a statistical caveat. Nothing is redundant with the schema.

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 read-only analytical tool with a full output schema, the description is nearly complete: purpose, selection intent, extra returned content, and a caveat about confidence ranges. Only edge cases like too little history to fill both blocks are unaddressed.

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 parameters are already documented. The description reinforces the meaning of `recent` and `previous` as block sizes, but adds no syntax or constraint detail 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?

States a specific verb (compare) and the exact resources compared: the most recent `recent` matches against the `previous` block before them. It clearly distinguishes itself from sibling listing tools like get_match_history and get_performance_report by being a two-block delta comparison.

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?

Gives concrete usage framing — 'use it to answer "what changed?" or "am I improving?"' — which tells the agent the intent that selects this tool. It offers no explicit exclusions or named alternatives among the many siblings, so it falls short of a 5.

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