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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds context about the tool's nature: it corrects US misconceptions and covers a specific set of topics. It goes beyond mere repetition of annotations by explaining the tool's effective behavior (providing Canada-specific facts) and its positioning as a prerequisite. Minor lack of detail on output format is offset by the output schema.

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 longer than ideal but densely informative. It front-loads the core purpose and lists specific correction areas, then gives a clear usage directive. Every sentence adds value, and the structure is logical: what the tool does, what it covers, and when to use it. The length is justified by the breadth of topics it addresses.

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's role as a knowledge base for Canadian credit mechanics and the presence of an output schema (which presumably covers return format), the description is complete. It identifies the key correction areas, states its prerequisite nature, and distinguishes from US fallback. With 15 siblings, it clearly carves out its niche. No essential information for an agent to decide whether to call it 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?

The schema provides full coverage of the only parameter, 'topic', with an enum and description explaining it can be omitted to get all topics. The description enumerates theme topics in prose but does not add additional semantic meaning beyond what the schema already conveys. Per the rubric, with high schema coverage the baseline is 3, and the description does not significantly enhance parameter understanding.

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's purpose: explaining Canada-specific credit reporting mechanics and correcting US-based assumptions. It specifies the resource (Canadian credit reporting) and the action (providing corrections), and distinguishes itself from general knowledge. The list of topics and the explicit instruction to call it before answering Canadian credit questions make its role 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 instructs when to use the tool: 'Call this before answering any question about Canadian credit scores, credit reports, bureaus, or reporting timing.' It also implicitly excludes US contexts by contrasting against US-based answers, and warns against using general knowledge. This is direct and actionable.

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