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

With no annotations, the description carries the full burden. It does disclose meaningful behavior: quotes are immutable single runs, billing is 'API consumption plus 100%', and prepayment is required. It does not say whether the quote expires, is re-quotable, or how it links to the checkout step.

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 tight sentences with the core action front-loaded and the input modes and cost terms following. Efficient overall, though 'immutable run' is compressed jargon that assumes prior context.

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 an 8-parameter, no-annotation, no-output-schema tool, the description covers the main input modes and pricing model but omits several parameters and the quote's lifecycle (expiry, link to checkout). Adequate but with clear gaps.

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 0% across 8 parameters, so the description must compensate. It maps idempotency_key, engine, service_id, brief and components to their input modes, but leaves files, model_tier and api_budget_usd (with its 0.01–50 bounds) unexplained.

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 (quote) and an object (a single immutable run), so the agent knows it generates a price/quote rather than executing a checkout. It naturally contrasts with siblings like create_rental_checkout and get_rental, though it never names them explicitly.

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?

The description explains how to supply inputs (idempotency_key plus engine/service_id/brief, or components for combined engines), which is real input-selection guidance. It stops short of stating when to prefer this over create_rental_checkout or when a quote must precede a purchase.

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