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

Annotations cover read-only/idempotent/open-world, but the description adds substantial context beyond them: one live read of Corporations Canada, six sections with a coverage block, an Ed25519-signed receipt verifiable offline at a published key, found/not_found/unknown verdicts with unknown explicitly free, and explicit non-goals (not advice, credit check or KYB).

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?

Purpose is front-loaded, but the body is two very long run-on sentences that bundle output fields, limitations, verdict semantics, pricing and signing into a dense block. Nearly every clause carries information, yet the wall-of-text form makes it harder to scan than it needs to be.

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?

With no output schema, the description carries return-value burden and does so: it enumerates the six sections, the found/not_found/unknown verdict space, the receipt/coverage artifacts, and the exclusions. An agent has everything needed to call it correctly and interpret results.

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% on the single query parameter, so baseline is 3, but the description adds real meaning: the value must be a nine-digit BN and why a company name cannot substitute for it. That clarifies the accepted input format and the constraint behind it beyond the schema's own wording.

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: Canadian company lookup / federal corporation register check, keyed by nine-digit Business Number. It also names what it is not (provincial/territorial registers, director/officer names), which lets an agent separate it from the generic check_entity_file siblings without opening a 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?

Gives clear selection conditions: BN only, name alone cannot reach the endpoint, and provincial/territorial corporations live in a different register this file does not read. It stops short of naming the specific sibling to use instead (e.g. check_entity_file_il or a provincial source), so it is context-rich but not fully routed.

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