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

Annotations already cover safety (readOnlyHint=true, idempotentHint=true, destructiveHint=false), yet the description adds real behavioral context beyond them: duplicate/already-included gear is rejected, multi-listing fees equal the sum of separate estimates, and shared inventory/combined checkout need confirmation. It stops short of describing failure modes or what the estimate payload contains.

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?

Three short sentences, front-loaded with the core action, then constraints, then fee semantics. Every sentence carries information, though terms like 'shared inventory' and 'combined checkout' are introduced without definition.

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 estimation tool with no output schema, the description covers the key agent-facing concerns: multi-item scope, duplicate rejection, fee aggregation, and the confirmation requirement for checkout. The main gap is that it does not clarify whether this is a pure read-only preview that never reserves inventory.

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 75% and the schema itself documents slugs, locale, and date formats, so the structured fields do most of the work. The description adds no parameter-level detail (e.g., that slugs must come from list_equipment or that the max is 10), so a baseline 3 is appropriate.

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+resource: 'Estimate selected listings together', which signals multi-listing estimation. It is distinguishable from the sibling get_rental_quote (single) and recommend_kit (suggestion), though it never names those siblings explicitly, so differentiation is implied rather than stated.

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?

Usage is implied by 'selected listings together' and 'shared inventory and combined checkout require confirmation', which hints at the multi-item scope and a downstream confirmation step. However, there is no explicit when-to-use guidance versus get_rental_quote or recommend_kit, and no stated prerequisites.

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