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

Annotations already establish readOnly/idempotent/non-destructive/closed-world, so the description correctly focuses on scope limits instead: it is illustrative, based on public rates, excludes freight and pass-through costs, and does not submit or approve anything. That is real added context beyond the structured fields, though return format and precision caveats are still unstated.

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?

Four sentences, front-loaded with the core action, then conditional requirements, then scope limits. No filler, no repetition of the tool name or obvious restatement.

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 does convey the shape of the result (an illustrative USD subtotal) and the conditional input requirements, plus what is excluded. It is nearly complete for this complexity level; only the response precision/format remains 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 0%, so the description carries the full burden, and it does the most important part: mapping each service enum value to the parameters it requires. It does not define units/months/orders semantics (e.g. billing period length) or note the numeric bounds, so it is not fully compensating.

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?

"Calculate an illustrative USD base-service subtotal from public rates" names a specific verb and a specific output artifact (illustrative cost estimate), which is clearly distinct from the sibling list_/plan_ tools. It stops short of explicitly contrasting itself with those siblings, so it lands just below the top mark.

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 gives per-service applicability rules (inspection needs sampleChecks; prep needs units; fulfillment needs orders; storage needs cubicMeters and months) and an explicit exclusion for one enum value ("Sourcing is quote-only"). What is missing is any pointer to an alternative tool when the user actually wants a real quote rather than an estimate.

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