Choose a statistical test

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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds that the result includes assumptions to check, but with no output schema it does not state the shape of the recommendation (a single tool name? ranked options? rationale text?), leaving the return value under-specified.

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?

Two sentences, both earning their place, with the purpose front-loaded and the routing rule second. No redundancy or filler.

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 7-parameter decision-aid with no output schema, the description omits how the recommendation is returned and under what conditions it declines to recommend. With read-only annotations already covering behavior and the schema covering params well, this is adequate but has clear gaps in explaining the response.

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 86% and the goal enum documents its tricky members (ab_test vs plan_ab_test), so the schema carries the semantic load. The description mentions none of the seven parameters and adds nothing beyond what the schema already explains. 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?

Names a specific verb and resource ('Recommends which test tool to run for a research question') and adds a second output ('with the assumptions to check'), which distinguishes it from sibling tools like run_test and check_assumptions. It stops short of naming those siblings explicitly, so the differentiation is inferable rather than stated.

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?

'Call this first when unsure' gives a concrete decision rule for invoking this routing tool before run_test or check_assumptions. It gives no guidance on when NOT to call it (e.g., when the test is already known), so an agent must infer that.

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