Compare WWDC topic coverage across two years

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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is fully covered. The description adds only that sessions are returned per year so the agent can see what was added — modest value beyond what annotations provide, with no mention of result ordering, empty-year handling, or truncation via limit.

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, zero filler, with the purpose stated first and the illustrative use case immediately after. Nothing is redundant and the reader learns the scope in the first clause.

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 five-parameter tool with full schema coverage and no output schema, the description does the one thing it must: it says the response contains sessions for each year, so the agent knows the return shape. Only minor gaps remain, such as how year_a/year_b ordering is enforced and what happens when a year has no matching sessions.

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 all five parameters, including the enum format and the limit bounds, are already documented. The description's 'framework, feature, or API area' phrasing for topic repeats the schema's own wording rather than adding format or syntax detail beyond it, 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?

States a specific verb (compares) and a specific resource (WWDC session coverage of a topic) with an explicit two-year scope. The cross-year comparison framing is inherently distinguishable from siblings like wwdc_topics_by_year or wwdc_search, which operate on a single year or a query.

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 quoted example question ('What's new in SwiftUI between 2024 and 2025?') implies when the tool is appropriate, which is useful context. However, it never names an alternative (e.g. wwdc_topics_by_year for single-year coverage, or wwdc_search for topic lookup) or states when not to use it, leaving routing to inference.

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