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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false), so the description's job is to add context, which it does: it discloses the rule source (pricing.json with a verification date), that the admin counts as one of the people, the Teams 5-person minimum and absence of platform fee, and that no transaction occurs. It does not describe what the response contains beyond a price figure.

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?

Two dense sentences, front-loaded with the plan shapes and followed by the compliance-relevant 'quote, not a checkout' caveat. Every clause carries information, though the first sentence is long enough that the pricing details and the source-of-truth citation run together.

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 could say more about what comes back — currency is never stated, nor whether a breakdown per person/period is returned. Still, the pricing model, minimums, and the non-transactional nature are covered well enough for an agent to call it correctly with the given inputs.

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%, so the baseline is 3; the description earns above that by adding pricing semantics not in the schema — per-person vs single-person pricing, the 5-person Teams minimum, no platform fee, and that the admin consumes a seat. It leaves the billing period distinction (yearly vs monthly discounting) to the schema enum alone.

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?

The description names a concrete verb and resource ('List price for Pro ... or Teams ... for a number of people, billed yearly or monthly') and immediately enumerates the plan shapes. No sibling tool (create_signature, list_layouts, get_facts) offers pricing, so the scope is unambiguous against the toolset.

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 explicitly sets the boundary 'This is a quote, not a checkout: the human pays in the app after signing up', which tells the agent when this tool applies and when it must not be treated as a purchase. It does not name a sibling alternative, but no sibling overlaps this function, so the practical guidance is sufficient.

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