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

Annotations already declare readOnlyHint/openWorldHint/idempotentHint, so the safety profile is covered. The description adds meaningful behavior beyond that: returns up to 100 stations, includes latest measurement values, defaults radius to 5 km, and notes public-domain licensing/no attribution. This gives an agent realistic expectations without contradicting any annotation.

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 organized, front-loaded with the core search behavior, and uses labeled sections for each filter mode. It is slightly longer than strictly necessary due to background context about OpenSenseMap and licensing, but those details are still useful for setting agent expectations and are not redundant with the schema.

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 an output schema present and annotations covering safety/idempotency, the description covers everything needed to select and call the tool correctly: all search modes, defaults, accepted example values, result size, and downstream tool routing. No essential invocation information is missing.

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 coverage is 100%, so the baseline is 3; the description adds value by giving concrete phenomenon values, default radius semantics, filter examples, and clarifying name substring behavior. It does not fully re-explain grouptag beyond the schema, but the added examples and defaults meaningfully improve parameter understanding.

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: 'Search OpenSenseMap crowdsourced environmental sensor stations' and then enumerates the distinct filter dimensions. It also names downstream siblings (box_detail, sensors_latest), so an agent can distinguish this search tool from those detail/latest-value tools.

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 description gives clear, mode-by-mode usage guidance: location search needs lat/lng plus max_distance, name search is substring-based, and phenomenon/exposure filters are enumerated with concrete values. It routes results to box_detail or sensors_latest, but it does not explicitly state when to prefer this tool over those siblings before calling.

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