Search recipients

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

Annotations already establish read-only, idempotent, non-destructive behavior, and the description adds useful scope details: it searches people this account shipped to before and matches by prefix rather than arbitrary substring. It still does not specify result limits or the shape of returned addresses.

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 short and front-loads the core purpose. There is slight redundancy between 'matching a name, email or phone' and 'matched by the start of their name (or email or phone)', but the UI context and usage hint earn their place.

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 lookup tool with no output schema, the description provides enough context to call it correctly: historical recipient scope, prefix matching, and intended downstream use. Return cardinality and exact address fields remain unspecified but are minor gaps.

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 0%, so the description must carry the parameter burden. It does explain that matching applies to name, email, or phone and is prefix-based, but it does not clearly document the `field` selector's default or the `query` length constraints.

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 states a specific resource and matching behavior: past recipients' addresses matched by name, email, or phone. It also distinguishes the tool from broader address tools by tying it to the Ship To autocomplete and to create_shipment's `to` field.

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 a clear positive use case: select one of these suggestions as create_shipment's `to`. However, it does not explicitly say when not to use it or name alternatives such as list_ship_from_addresses or parse_address.

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