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

Annotations already declare readOnlyHint=true, so 'Read-only' is largely redundant. The description does add genuinely new behavior: the weekend/IRS-holiday roll-forward adjustment and the inclusion of a deep link in the response, which an agent could not learn from annotations or schema.

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?

One dense sentence with the scope and the holiday-roll-forward rule front-loaded, plus a two-word safety tag. Efficient and well-ordered, though the trailing 'Read-only.' duplicates the annotation and costs a little space.

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 no output schema, the description usefully characterizes the return payload (four due dates plus a deep link) and explains the roll-forward rule. Only minor gaps remain, such as date formatting/timezone, which are unlikely to block correct invocation.

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 the single taxYear parameter is documented with an enum and its own description, so the schema carries the full burden. The description adds no syntax or format detail beyond what the schema already says, making baseline 3 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?

States a precise verb ('Return') and resource ('the 4 federal quarterly estimated tax payment due dates for a tax year'), and even enumerates the four dates. It is clearly distinguishable from the sibling estimateQuarterlyTax (calendar lookup vs. tax estimation), so an agent can route without opening either 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?

Usage is only implied: the agent can infer this is the tool for 'when are my estimated payments due', but the description never states when to prefer it over estimateQuarterlyTax or any conditional/prerequisite. With one obvious sibling and no exclusion language, this is minimum-viable context.

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