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 meaningful behavioral context: the parameter daysPastDue 'changes which part of the answer leads', and the actionable insight about the 30-day gap. This goes beyond annotations and 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 concise and well-structured. It opens with the core purpose, then the usage context, and ends with a key differentiating insight. Every sentence contributes value, and the structure makes it easy for an agent to parse.

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 an output schema and only one optional parameter, the description is complete. It covers what the guide includes, when to call, and the key Canadian-vs-American nuance. There is nothing an agent needs to know to invoke it correctly that 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 already fully documents the daysPastDue parameter with a clear description. The tool description adds an extra layer of meaning by explaining that the parameter changes which part of the answer leads, which is not in the schema. Since schema coverage is 100%, baseline is 3, and the additional behavioral nuance earns a 4.

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 explicitly states what the tool does: it explains the consequences of a missed payment in Canada, covering the 30-day reporting gap, the R1-R9 scale, and how long a late payment stays on file. It is clearly distinct from sibling tools like how_long_it_stays by covering a broader scope, and it specifies the exact resource (missed payment guide).

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 gives explicit conditions for use: 'Call this for a missed, late, or nearly-late payment, or for "how long will this hurt me".' This is clear and actionable. However, it does not name sibling alternatives or specify when NOT to use it, which would have been an extra point.

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