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

With no annotations, the description carries the full burden and does useful work: it discloses that the call is PAID ($0.005 via x402/USDC on Base), which the schema and annotations never state, plus the upstream provider (Open-Meteo) and that city geocoding happens server-side. It omits error behavior for unresolved city names and whether results are cached, so not a 5.

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?

One sentence with the critical cost/mechanism front-loaded, followed by the resource, return fields, and provider. No filler and nothing an agent must read past the first clause to learn.

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 single-parameter, fully-documented tool with no output schema, the description supplies purpose, return fields, payment requirement, and provider. No output schema exists, so listing the returned fields is the right level of detail.

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% with a single documented 'city' parameter, so the baseline is 3. The description adds only marginal semantics ('any city worldwide', geocoding) beyond the schema's own example.

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+resource ('current weather for any city worldwide') and enumerates the returned fields (temperature, feels-like, humidity, wind, conditions). No sibling tool covers weather, so it is trivially distinguishable from the crypto/UUID/URL utilities in the list.

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?

Usage is implied by the resource described, but there is no explicit when-to-use statement, no exclusions, and no pointer to any alternative (there is no sibling weather tool, so alternatives are naturally absent). Adequate but leaves context to inference.

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