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

Annotations already indicate destructiveHint=true, so the description's statement 'WILL mutate state on the user's Shippo account' aligns and reinforces this. Additionally, the description notes case-insensitive name lookup, which provides extra behavioral context beyond the annotations.

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 extremely concise: three sentences that front-load the core purpose, then provide usage guidance and prerequisites. Every sentence is necessary and contributes value without redundancy.

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?

Given the presence of an output schema and annotations, the description is complete. It covers purpose, usage constraints, behavioral impact, and prerequisites. No critical information is missing.

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?

Input schema has 100% description coverage for its two parameters. The description does not add new semantics beyond what is already in the schema for 'name' and 'arguments'. Baseline of 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?

The description clearly states the tool's purpose: executing write Shippo API operations. It provides specific examples (Create*, Update*, Delete*, *Refund) and distinguishes it from the sibling shippo_read_execute_tool by explicitly noting that reads are rejected.

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 gives explicit instructions on when to use this tool (only for 'write' operations as per shippo_describe_tool) and when not to (read operations, directing to shippo_read_execute_tool). It also outlines prerequisites: get operation name from shippo_list_tools and argument shape from shippo_describe_tool.

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