get_stats

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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds no additional behavioral context beyond the aggregation logic described in the output list (e.g., grouping by location/stakes/month), which is more about output structure than side effects. No contradiction, but no extra transparency beyond 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?

This is a single sentence that front-loads the verb 'Compute' and immediately specifies the resource and outputs. The list of breakdowns is concise and useful, with no wasted words.

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?

Given the tool has no output schema and only a readOnly annotation, the description adequately explains what the tool returns (total profit, win rate, etc.) and the grouping dimensions. However, it omits default behavior when optional parameters are omitted (e.g., whether stats cover all time or all sessions), leaving a minor gap.

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 provides 100% description coverage for all five parameters, including date range, type, staking, and currency. The description does not add any detail about parameter formats or defaults beyond what the schema already gives, so it adds no incremental value here (baseline 3).

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 opens with 'Compute aggregate statistics from poker sessions,' a specific verb+resource that clearly distinguishes this from the sibling get_sessions tool, which presumably returns raw session data. It enumerates specific outputs (total profit, win rate, etc.), making the purpose unambiguous.

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 that this tool is for aggregate/statistical queries, contrasting with get_sessions for raw data, but it does not explicitly state when to use one versus the other or provide exclusions. The context is clear, but there is no direct mention of alternatives.

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