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

Goes well beyond the readOnly/openWorld/idempotent annotations: it discloses default and maximum result counts, that an empty result yields a 404 and is not billed, and the full payment model (x402 USDC on Base, $0.001 per successful call, unpaid calls return a PaymentRequired object). Payment and error semantics are exactly the kind of behavior annotations cannot express.

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?

Three sentences, front-loaded with the usage condition and backed by result shape, error behavior and pricing — no filler. The first sentence is clause-heavy (usage, count, default, max, output fields all in one), which slightly hurts scannability.

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 no output schema, the description still enumerates the returned fields, states the result cap, and covers the failure/billing paths an agent must handle. Nothing material is missing for calling this tool correctly in a paid-API context.

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%, with both q and limit already documented including the same 1-10 range and default of 5, so the description's mention of default/max only repeats the schema. The listed return fields (lat/lon, display name, type, country) describe output rather than adding parameter meaning; 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 and resource (geocode search over places/addresses) with an explicit multi-result scope ('returns up to limit matches'), which cleanly separates it from the single-result geocode, geocode_reverse and the fx/time/weather/holiday siblings. An agent can tell what this returns without opening the schema.

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?

Gives concrete trigger conditions: 'autocomplete-style place pickers' and 'when the query is ambiguous'. It does not name the alternative to pick when the query is unambiguous (i.e. the single-result geocode tool), so the routing rule is one-sided rather than complete.

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