firestarter_shipping_estimate

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

Annotation Contradiction: The description states 'read-only: no execution is created, no approval, nothing is bought', but annotations include readOnlyHint: false. This directly contradicts the declared read-only behavior. The description does provide additional useful context about no side effects, but the contradiction with structured metadata is a serious issue.

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?

The description is longer than average but well-structured, with the core purpose and read-only guarantee front-loaded. Every sentence adds value, though it could be slightly tightened without losing essential caveats.

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?

No output schema exists, so the description must explain return values; it mentions 'rated delivery options (price, ETA, carrier when known)'. It also covers typical use cases and clarifies the informational nature of results. While thorough, it could have included more detail on how estimates degrade without street addresses, but it is adequate for the tool's complexity.

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 baseline is 3. The description adds meaningful guidance beyond the schema: explains that a full street address is NOT needed, that address_id is preferred when available, and that country+zip/city is sufficient. It also notes that street-less destinations may get estimate tiers, adding context not present in the parameter descriptions.

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 clearly states the tool estimates shipping for a listing before purchase, with a specific verb ('Estimate') and resource ('shipping for a listing'). It distinguishes from siblings by explicitly noting it is not for execution or approval, and contrasts with firestarter_execute and firestarter_shipping_options.

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?

Provides explicit context for use ('while the buyer is still browsing'), examples (firestarter_preview, catalog_search, share links), and explicitly says when not to use it ('NOT a menu to approve from'). Names alternatives for the actual purchase path (firestarter_execute, firestarter_shipping_options).

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