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

Annotations already declare this is a read-only, non-destructive, closed-world tool, so the safety profile is covered. The description adds a genuinely useful piece of behavior in the merge rule ('each group is a set of filters merged over the optional shared filters'), but it never says what an 'evidence profile' actually returns, and there is no output schema to fill that gap.

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 compact sentences, with the core operation front-loaded and the examples immediately after. There is no filler, but the second sentence is dense enough that it is easy to miss the merge rule on a skim.

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 nested 3-parameter comparison tool with no output schema, the description explains how input is composed but not what comes back per group: no mention of counts, pooled effect direction, or the top studies list. What it does say is accurate, but an agent still has to guess at the deliverable.

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?

With 67% schema coverage the schema already documents most filters, but the description adds semantics the schema does not: the 2–4 cardinality and the precedence relationship between per-group filters and the shared block. The optional top_studies parameter and its default are left entirely to the schema, which is a minor gap.

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 names a specific operation and resource: 'Side-by-side evidence profiles for 2–4 groups of studies'. Two concrete examples clarify what a comparison means here. It reads as distinct from the sibling aggregate_studies or get_condition_evidence, but it never explicitly says so.

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 examples ('inhalation vs drinking water for one condition, or two conditions') imply the comparison use case, but there is no explicit guidance on when to choose this over aggregate_studies or get_condition_evidence, and no stated preconditions.

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