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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and openWorldHint=false, so safety is covered. The description adds substantive domain behavior beyond that: the derivation rule (65 days = 60 from receipt + 5 presumed mailing days) and the fast-appeal cut-off (noon the day before care ends). It does not clarify what happens when both or neither date is supplied.

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?

Front-loaded with the tool's purpose, then the two input scenarios, with the precedence caveat last. Dense but every sentence carries information; the parenthetical rule explanation slightly increases cognitive load but earns its 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?

There is no output schema, so the description correctly carries the burden of explaining results, and it does so (65 days from notice_date; noon the day before care_end_date). For a two-parameter read-only calculator this is nearly complete, with only the both-params / neither-param behavior left ambiguous.

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 coverage is 100% and both params are optional, so the baseline is 3, but the description adds real meaning the schema lacks: it ties each parameter to a specific output (reconsideration deadline vs fast appeal) and identifies the source documents. The interaction rule when both are provided is still unstated.

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?

Opens with a specific verb+resource ('Calendar arithmetic for Medicare Advantage appeal deadlines'), which is unambiguous and clearly distinct from siblings claim_back_services, list_guides and read_guide. An agent can identify the tool's function from the first clause alone.

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 tells the agent exactly which input selects which scenario: notice_date for the plan reconsideration deadline, care_end_date for the fast appeal. It also states a precedence rule ('The notice's own instructions come first'). However it never names an alternative tool or states when not to use this one, so it stops short of 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.