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

Annotations already declare readOnly=true, idempotent=true, openWorld=true and destructive=false, so the safety profile is covered. The description adds genuinely new operational context: free/no-key, a required valid User-Agent, and a 1 request/second rate cap. The User-Agent requirement is slightly awkward since no header parameter exists, but the rate limit is valuable disclosure.

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?

Compact and front-loaded: purpose first, then constraints, then return shape, then usage cue. Only mild redundancy in listing return fields when an output schema exists. Zero filler sentences.

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 the return values need not be enumerated, and the annotations carry the safety profile, so the remaining need is operational context - which the rate-limit/no-key note supplies. Only gap is that the User-Agent requirement offers no actionable path for the agent.

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% - both query and limit are documented with defaults and examples in the schema itself. The description restates that a place/address is geocoded but adds no syntax, format, or limit semantics beyond the schema, so the baseline of 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 (geocode) and resource (place name) and names the exact provider, OpenStreetMap Nominatim. Among a sibling set of mostly data-search tools, there is no overlapping geocoder, so the purpose is unambiguous.

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?

"Use for address/place coordinates" gives a clear positive trigger for when to reach for this tool. It does not name an alternative or an exclusion condition, but no sibling overlaps this capability, so guidance is effectively complete.

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