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

With no annotations, the description carries the load and does add real context: it declares the call is free (cost), that results are approximate in lat/lon (accuracy caveat), and that FSAs are accepted. It omits error behavior, rate limits, and response shape for misses, keeping it short of full 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?

One compact sentence with the cost qualifier and the key resource front-loaded. Every clause adds information; nothing is redundant.

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 one-parameter lookup with no output schema, the description adequately covers input flexibility and the returned fields plus an accuracy caveat. A format example or note on invalid-postal-code behavior would close the remaining gap.

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 0%, so the description must compensate, and it does by clarifying that the single postal_code accepts either a full postal code or an FSA. It stops short of giving format examples or normalization rules.

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 ('Resolve') and resource ('Canadian postal code (or FSA)') and names the outputs (city/province, approximate lat/lon). It doesn't explicitly contrast with the siblings batch_postal or distance, but the singular 'a postal code' implicitly separates it from the batch variant.

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 'FREE' flag and by the single-record phrasing, which suggests using this instead of a paid or batch call for one lookup. There is no explicit when-to-use/when-not statement or named alternative, so an agent must infer the routing.

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