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

Annotations cover only readOnlyHint and openWorldHint; the description adds genuinely new behavior: deterministic/no-AI execution and a concrete cost model ($0.001 USDC per call via x402 on Base, first 5 calls/day per client free), including an implicit rate limit. It omits what happens under modified conventions when consecutive days are closed, but adds real value beyond the annotations.

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 and scope are front-loaded in the first clause, conventions follow, then use cases, then pricing. Every sentence earns its place with no filler or redundancy.

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 small, deterministic, read-only computation tool with no output schema, the description covers purpose, conventions, calendars via schema, use cases and cost. It could note the return value shape (the adjusted date), but nothing an agent needs to select or call the tool correctly is missing.

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% and each parameter, including calendar aliases and the convention default, is documented in the schema. The description merely repeats the four convention names already listed in the schema and adds no semantics (e.g. how modified_following differs from following), so baseline 3 applies.

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+resource: it states that it rolls dates landing on weekends/holidays using a named business-day convention, and lists the four conventions. It implies but never explicitly distinguishes itself from close siblings like is_business_day (check only) or add_business_days (shift by N), so it falls short of a 5.

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?

"Typical for payment, coupon and invoice due dates" gives domain context for when it is appropriate, which is more than nothing. It gives no when-not guidance and never routes the agent to a sibling tool such as settlement_date or is_business_day, so usage remains implied rather than explicit.

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