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

The description explicitly states that the tool 'does not fetch live data or change accounts,' aligning with the readOnlyHint and destructiveHint annotations. It also clarifies that it returns bundled reference material with source links, setting accurate expectations for behavior.

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 fairly concise and front-loads the primary use case, but it repeats the 'Returns...' phrase twice. This minor redundancy does not significantly harm clarity.

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?

The description provides enough context for a no-parameter informational tool: it names the topic, the categories covered, that durations vary by bureau and province, and that source links are included. It does not specify output format, but for a simple reference lookup this is adequate.

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 tool has zero parameters and the schema coverage is effectively 100% with an empty properties object. The description does not need to explain parameters, so the baseline score of 4 is appropriate.

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 the tool answers 'how long will this stay on my credit report' and lists the specific retention categories covered (closed accounts, late payments, collections, etc.). This clearly distinguishes it from sibling tools like explain_missed_payment or explain_when_issuers_report.

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?

It provides a clear use case ('use this for any how long will this stay question') but does not explicitly mention when to prefer alternative tools such as explain_missed_payment or simulate_paydown. Some implicit differentiation exists via the retention focus, but no direct exclusions are stated.

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