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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses the commercial term ($0.002 USDC per successful call), the payment mechanism and rails (x402 on Base, Solana or Arc), and a failure policy ('failed calls are not charged') — exactly the auth/cost context annotations cannot express. It also repeats the definitive scope limit (metadata only) that guards against misinterpretation of results.

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 compact sentences: source and returned fields first, the scope exclusion second, the pricing/failure policy last. No filler, no repetition of schema detail, and the most decision-relevant content is front-loaded.

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?

An output schema exists, so return field documentation is a bonus rather than a necessity. Source, jurisdiction, scope limit, cost and charged-on-failure policy are all present; nothing an agent needs to decide to call this tool or interpret the charge 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% and both parameters carry descriptions (search text 2–80 chars, rows 1–10 default 5), so the schema does the work. The description only adds that the query is a 'search term', which is a marginal gain; baseline 3 applies when the schema is fully self-documenting.

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?

Names a specific resource (Canadian federal open datasets from open.canada.ca via the CKAN API) and enumerates the fields returned: title, publisher, licence, last modified date, resource count, dataset link. The scope clause 'Catalogue metadata only, not the data files' immediately separates it from the other national/regional open-data siblings such as gov_australia_data_gov_au or gov_data_gov_uk.

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?

'Catalogue metadata only, not the data files' tells the agent when this tool is the wrong choice (when actual dataset contents are wanted), and the 'for a search term' framing clarifies the query-driven usage. It stops short of naming a concrete alternative for retrieving the underlying files, so it is clear context without explicit routing.

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