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

Goes well past the readOnlyHint/openWorldHint annotations: it states the content boundary ('Catalogue metadata only, not the data files') so the agent knows records describe datasets rather than contain them. It also discloses the commercial model — $0.002 USDC per successful call via x402 on Base/Solana/Arc, with failed calls not charged — which is exactly the kind of behavioral cost/side-effect information annotations cannot carry.

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?

Front-loaded with the resource and its key scope caveat, then siblings, then pricing; every clause carries information. The related-tools clause is a slightly dense run-on and the returned-field enumeration partially duplicates the output schema, but nothing is filler.

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 two-parameter, read-only search tool with an output schema, annotations and full parameter documentation, the description covers everything an agent needs: what it returns, that it is metadata not files, which siblings to use instead, and the cost model including no charge on failure. Nothing material is left to inference.

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 already document their types, ranges and the rows default (5), so the schema does the heavy lifting. The description adds only that the search is 'for a search term' and lists output fields; it gives no extra semantics for q beyond the schema's 2–80 character note or for rows. 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?

The description names a specific verb and resource ('Canadian federal open datasets from open.canada.ca (CKAN API)') and enumerates the returned fields (title, publisher, licence, last modified, resource count, link). The clarifying clause 'Catalogue metadata only, not the data files' removes the most likely misreading, so an agent can distinguish this from data-file or non-Canadian sources 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?

Explicit routing is given for two siblings with conditions attached ('gov_dati_gov_it_italy_open_data when you need Italian open government datasets', 'gov_royallepage_canada when you need Royal LePage homes for sale'), which is strong. The gap is that the closest alternatives in the sibling list — gov_data_gov, gov_data_gov_uk, gov_govdata_germany, gov_australia_data_gov_au — are other national open-data portals and are not named, so the agent gets no explicit signal on jurisdiction choice among them beyond 'Canadian federal'.

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