set_default_customer_address

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

With no annotations, the description must disclose behavior on its own. It states the effect (marks address as default) and the return value (the address now marked default), which is useful. However, it does not mention side effects (e.g., previous default being unset), permission requirements, or error behavior, leaving some gaps for a mutation tool.

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 two short sentences with no filler. It front-loads the core action and then gives the endpoint and return value. Every word earns its place, making it highly efficient and well-structured.

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 simple two-parameter mutation tool, the description is complete: it explains what happens (sets default), shows the endpoint, and tells the caller what to expect in the response. With no output schema, the explicit return statement fully covers the success response. The tool's simplicity means no additional context is necessary.

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?

The input schema already provides full coverage (100%) with descriptions for both customer_id and address_id. The description adds a minor bit of context by showing how they appear in the endpoint URL, but it does not enrich the semantic meaning beyond what the schema already offers. 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 specific action: 'Set a customer's default address' via a dedicated endpoint. It identifies the resource (customer address) and the precise operation (mark as default), distinguishing it from sibling tools like update_customer_address or add_customer_address.

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 implies this is the right tool for setting a default address (calling it 'Sapo's dedicated endpoint'), but it does not explicitly compare to alternatives or state when not to use it. No explicit 'use this instead of X' guidance is given, leaving the agent to infer from the tool name and sibling list.

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