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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint false, so the safety profile is clear. The description adds valuable behavioral context: it names the underlying API (CKAN Action API) and states that no authentication is required, which are not covered by annotations. It also mentions the return fields, but that is partly redundant with the output schema. Overall, it complements the annotations without contradicting them.

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?

The description is three sentences with no filler. The first sentence states the purpose and outputs, the second provides essential usage guidance for filter slugs, and the third gives the data source and authentication context. Every sentence contributes meaningful information, and the key purpose 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?

Given the tool has 4 optional parameters, a complete output schema, and comprehensive annotations covering safety, the description covers the remaining essential aspects: what it searches, how to construct filters (via reference tools), and that no auth is needed. The rows parameter and return format are documented in the schema, so nothing critical 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?

All parameters have schema descriptions with 100% coverage, so the baseline is 3. The description adds semantic value by explaining that subject and organization parameters require slugs from the reference list tools, which is not stated in the schema. It also maps the search dimensions (free text, subject, department) to the parameters, reinforcing the schema's intent. This extra guidance pushes it above the baseline.

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 clearly states the tool searches the Government of Canada open data catalog by free text, subject, or department, and lists the specific fields returned (id, title, notes, organization, subjects, dates). It distinguishes itself from sibling tools like open-canada.datasets.detail (which presumably fetches a single dataset) and the reference list tools, making its purpose unambiguous.

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?

The description explicitly directs users to open-canada.subject_list and open-canada.organization_list to obtain valid filter slugs, which is essential for using the subject and organization parameters correctly. It also states the search dimensions (free text, subject, department), implying when this tool is appropriate. However, it does not explicitly contrast with open-canada.datasets.detail for cases where a specific dataset ID is known, so the guidance is good but not fully exhaustive.

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