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

Annotations already declare read-only, idempotent, closed-world semantics, but the description adds important non-annotation behavior: one failing shipment does not stop others, and each failure states a reason plus whether resubmission can help. It also scopes explain to the first 25 shipments. It does not mention the API-key-dependent call limits, though those are covered in the schema.

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 purpose, then failure behavior, then the explain option. Every sentence contributes information and nothing is repeated or padded.

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?

Covers batch execution, failure isolation, retry guidance, and the explain limit, while the schema supplies full nested parameter documentation and call limits and annotations cover safety. The only gap is that the success/response shape is not described at all, though no output schema exists to rely on either.

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%, so the schema already carries all parameter semantics and the baseline is 3. The description's only additional parameter-adjacent detail is that explain adds calculation sheets for the first 25 shipments, which largely restates the schema's 'up to 25' note. It adds no extra syntax or constraints for the shipments array.

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 ('Calculates several shipments at once'), and explicitly anchors the per-shipment behavior to the sibling calculate_shipment, so the batch-vs-single distinction is clear without opening either schema. The mention of explain further grounds the tool's scope.

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 phrase 'several shipments at once' and the reference to calculate_shipment make the batch use case clear relative to the single-shipment sibling. It also explains when to set explain. However, it never states a when-not condition or explicitly says to use calculate_shipment for a single shipment.

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