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

Goes well beyond annotations: discloses per-call cost, the free-on-no-match policy, the 10-result cap with explicit ranking order (exact, prefix, contains; active first), address truncation to city/province/three postal characters, exclusion of director names, and that results are not the official record. These are exactly the behavioral facts an agent cannot get from readOnly/idempotent hints.

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 cost warning is correctly front-loaded as the first two words, and every clause conveys new information (coverage, ordering, fields, truncation, caveats). It runs as one long paragraph rather than grouped lines, which slightly hurts scannability.

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?

There is no output schema, so the description carries the full return-value burden and does so thoroughly: every returned field is enumerated in order, along with totals, attribution, and the known limitations (no directors, truncated address). An agent can call this and interpret the response correctly without further information.

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%, including the 'give this or corporation_number, not both' constraint, so the description only restates the two lookup modes without adding format or matching semantics beyond the schema. Baseline 3 is appropriate when the schema already carries the parameter detail.

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 and resource ('look up a federally incorporated corporation') plus the exact dataset ('Corporations Canada's published Federal Corporations data') and the two lookup keys. No sibling tool covers corporation data, so no disambiguation is needed, and the scope is 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?

Makes clear this is a paid, per-call lookup and that unsuccessful lookups are free, which is the key decision input a caller needs. It also implicitly routes the agent to either a name or number query, though it does not name any alternative tool or state exclusions.

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