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

Annotations already establish readOnlyHint=true and destructiveHint=false, so the description carries a lower burden. The description adds valuable transparency by stating that the tool will not provide a specific day because no Canadian issuer publishes exact transmission dates. It also explains the scope of what will be covered (cadence, delays, bureau differences). This exceeds what annotations alone convey and sets accurate expectations for the user.

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 at three sentences, front-loads the core content (cadence, delay, bureau discrepancy), then states the limitation, and closes with explicit usage triggers. No word is wasted; it is well-structured and easy to parse. The information density is high without being verbose.

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?

For a zero-parameter informational tool with an output schema present, the description is complete. It covers what the tool will explain, what it will not (specific days), and when to call it. The output schema handles return-value details, so no further information is needed. The tool's complexity is low, and the description fully covers its usage and limitations.

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 0 parameters, and schema coverage is 100% (empty schema fully documented). Per the baseline rule for 0-parameter tools, this scores a 4. The description doesn't need to detail parameter semantics, but it does add context about how the tool is invoked (via conversational queries) that complements the empty schema.

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: it explains the monthly reporting cadence in Canada, how long changes take to appear on a credit file, and why Equifax and TransUnion files differ. It also explicitly mentions what is not knowable (specific transmission days). This is a specific, non-tautological description that distinguishes the tool's scope from typical credit tools. The title reinforces the purpose.

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 provides concrete usage triggers: 'Call this for "when will this show up on my credit report" or "what day does my bank report"'. This gives clear context for when to invoke the tool. However, it does not explicitly name alternatives or state when NOT to use this tool, so it falls short of full guidance. With many siblings like statement_calendar and find_statement_close_date, explicit exclusions would have improved it further.

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