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

Annotations already declare the safe read-only, idempotent, closed-world profile, and the description still adds real behavior: that weekend/holiday shifts are pre-applied and that each date is tagged as IRS-published vs. standing-rule with a source. It does not otherwise describe latency, caching, or boundary behavior, so it stops short of the highest mark.

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 trigger condition, then parameters, then return semantics, then scope limits. It is efficient overall, though the sentence enumerating returned date types partially repeats what the output schema already provides.

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 annotations, a full output schema, and complete parameter coverage, the description only needs to cover scope and intent, and it does: audience (US federal individual), inputs, what is returned, preprocessing already applied, and explicit out-of-scope cases.

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. The description restates that 'year' is the year income was earned and clarifies that as_of drives 'next', which is mostly duplicative of the schema text rather than adding new syntax or constraints.

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?

States a specific verb and resource ('list US federal individual tax dates') with concrete trigger phrasings, and it is clearly distinguishable from siblings like estimate_federal_tax or get_tax_parameters. An agent knows exactly what this returns without opening the schema.

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?

Explicit trigger conditions are given ('when the user asks when a US federal individual tax date falls') with several example queries, plus clear exclusions ('does not cover state deadlines or disaster-relief postponements'). This tells the agent both when to call it and when not to, which is exactly the routing decision needed.

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