Get label prices (seller)

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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses the important current behavior: it returns 501 labels_coming_soon until booking goes live, and this is expected. It also states the API key requirement and points to the self-ship alternative, which is exactly the extra context an agent needs.

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 compact and front-loads the seller/state context plus the important 501 caveat. However, the opening fragments ('Seller, state escrow_held, shipped items') are slightly awkward and reduce immediate readability.

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?

It covers the most urgent operational context: current unavailability, expected 501 response, auth requirement, and fallback. It still omits the sole parameter's meaning and does not describe the success response shape, which matters because there is no output schema.

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?

There is one required parameter, transaction_id, and schema description coverage is 0%, but the description never mentions it or explains what transaction it should identify. The schema supplies only type and pattern, so the description does not compensate for the missing semantic guidance.

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 identifies the seller-specific action: retrieving carrier options for a prepaid label in escrow_held/shipped contexts. It distinguishes the tool from actual label booking by saying booking is coming soon, though the phrasing is telegraphic and does not explicitly restate that it returns prices/rates.

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 gives clear usage conditions ('Seller, state escrow_held, shipped items') and a fallback when unavailable ('self-ship with mark_dispatched instead'). The guidance is practical, but the fragmented wording makes the when-to-use rule less immediately readable than an explicit sentence.

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