Get courier phone

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

Annotations already declare readOnlyHint=true and idempotentHint=true. The description adds valuable context: the number is temporary, has a TTL, and includes specific error codes (400, 404, 409). This goes beyond the annotations without contradicting them.

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 a single, well-structured sentence listing output fields and error codes. It is front-loaded and every word adds value, with no fluff or repetition.

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 no output schema, the description explains the return values and errors sufficiently. It could mention what constitutes an 'active claim' more explicitly, but the error information compensates. The context is otherwise complete for a simple read tool.

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% (both claim_id and point_id have descriptions). The tool description adds no extra parameter-level detail, relying entirely on the schema. 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 function: providing a temporary forwarded phone number to call the courier of an active claim. It specifies the returned fields (phone, ext, ttl_seconds), distinguishing it from siblings like get_confirmation_code or get_tracking_links.

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 notes the tool is for active claims and lists a 409 inappropriate_status error for completed orders, implying when not to use it. It doesn't explicitly name alternatives, but the context is clear and the sibling list provides alternatives.

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