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

With no annotations, the description carries the burden. It discloses the return structure (summary, readings, metadata) and recommends presenting the summary first. It does not explicitly state whether the operation is read-only or mention any side effects, though 'get' implies a read operation.

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 description is concise and well-structured: a one-sentence summary, a clear explanation of return value usage, and a compact Args list. Every sentence serves a purpose without redundancy.

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 no output schema, the description adequately explains return values and parameter semantics. It could be more complete by noting the default radius conflict and explicitly distinguishing from sibling tools, but it covers the essential operational aspects.

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 description adds substantial meaning beyond the bare schema by explaining location formats, giving examples for filters, and specifying radius behavior. However, there is a discrepancy: the description states radius_km default as 2.0, while the schema says 3.5, which could mislead an agent.

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 a specific verb and resource: 'Get the most recent air quality readings near a location, with health context.' This clearly distinguishes it from siblings like get_historical_aq and get_aqi_summary, emphasizing current conditions and health context.

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?

It clearly indicates use for immediate air quality readings by saying 'most recent', and explicitly instructs to 'Present the summary to users first', which guides output usage. However, it does not explicitly contrast with alternatives or state 'when not to use' this tool.

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