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

Annotations already declare readOnlyHint=true and openWorldHint=false, yet the description still adds real behavioral context: the 3.5% processing fee is baked into the number, nothing is reserved, and unavailable placements are refused rather than silently adjusted. These are behavior facts an agent cannot get from the structured fields.

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 short, front-loaded sentences with no filler: pricing behavior first, then when to use it, then the non-reservation caveat and the failure mode. Nothing is padded, though the sentences are terse fragments rather than maximally economical.

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 read-only, single-parameter quoting tool with no output schema, the description covers purpose, cost semantics, side-effect absence, and error behavior. It could still say what the response contains (a total, per-placement breakdown, currency), which is the only meaningful gap.

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 there is a single nested 'items' parameter whose id/quantity semantics are fully documented in the schema. The description adds no parameter-level detail (e.g., that quantity accepts multiples or how negative quantities behave), so it sits at the baseline.

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 ('Price a set of placements') and adds the scope detail that checkout fees are included. It implicitly distinguishes itself from create_order by saying it is used to quote 'before creating an order', though it never names an actual sibling tool.

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?

Gives clear usage context ('give a client a total before creating an order') and an important exclusion ('Quoting does not reserve anything'). It does not address when to prefer compare_placements, plan_placements, or get_availability instead, so the alternative-routing is incomplete.

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