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

Annotations cover the safety profile (readOnly, idempotent, non-destructive), and the description adds substantive disclosure about the response: plain-language meaning, who fixes it, billability derived from group code, and a conditional letter link. With no output schema, this return-shape detail carries real weight; only per-code edge cases (invalid/unknown codes) are unaddressed.

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 in one sentence, with the examples and return-content list following compactly. The three example queries are slightly redundant with one another but each demonstrates a different code format, so they mostly earn their place.

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 only 2 simple params, no output schema and annotations handling safety, the description is nearly sufficient: it covers input formats, output semantics, and downstream behavior. Only multi-code batching behavior and invalid-code handling are left implicit.

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 description coverage is 100%, so the baseline is 3, but the description adds genuine meaning: the CO/PR/OA/PI group-code explanation teaches the agent how the 'code' value is composed, and it notes plan_type is carried into the letter link. That is value beyond the schema text.

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?

Specific verb 'explain' plus the exact resource 'denial codes on an Explanation of Benefits', reinforced by real example inputs (CO-50, PR 204, N130). It is clearly distinguishable from siblings like draft_appeal_letter or get_appeal_deadlines, which is exactly what the letter-link framing implies.

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 three quoted user phrasings make the trigger condition concrete and unambiguous. It stops short of explicitly routing away from siblings (e.g. 'for deadlines use get_appeal_deadlines'), so it is clear context but not full when/when-not guidance.

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