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

Annotations already establish readOnly, non-destructive, closed-world behavior, so the bar is lower. The description adds genuinely useful behavioral context beyond that: it only structures what the user supplied and reports missing elements rather than inventing them, which tells the agent how to interpret an incomplete result.

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 pipe-delimited layout front-loads the purpose and then sections USE WHEN, ALIASES and RETURNS, so an agent can scan it quickly. The bilingual title repetition and long alias list add some noise but each block carries routing value.

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?

With no output schema, the RETURNS line correctly states what comes back (the four-element structure plus a list of missing elements). Combined with the no-invention rule, an agent has enough to invoke and interpret the tool, though the relationship to pico_refine remains undeclared.

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% and the single nested object parameter is documented as containing population, intervention, comparison, outcome and topic. The description adds no additional meaning about those fields, so the 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?

The description states a specific verb and resource ('structures' a PICO), labels its role as 'design flow', and enumerates the surface forms it handles ('refine my PICO', 'turn this sentence into PICO', 'how to split PICO'). It does not differentiate itself from the close sibling pico_refine, and in fact lists 'pico refine' as an alias, which muddies the boundary.

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?

Explicit USE WHEN triggers give the agent concrete user phrasings that should route here, which is stronger than most definitions. There is no when-not guidance and no named alternative, so the agent must infer whether pico_refine is preferred in overlapping cases.

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