Get saved addresses

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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description still adds real context beyond that: the hard cap of 5, deduplication, newest-first ordering, the empty-list meaning, and the explicit warning that it selects nothing. It does not cover auth/permission nuances, but nothing suggests those are in play.

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 sentences, front-loaded with what is returned and in what order, followed by usage and the failure case. Every sentence carries information; nothing is redundant with the schema.

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?

An output schema exists, so return-shape details are unnecessary, yet the description still supplies the ordering and cap that shape agent expectations. For a zero-param read tool with strong annotations, nothing an agent needs before calling 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?

There are zero parameters, so there is nothing to mis-specify, and the baseline is 4. The description adds useful semantics by explaining that matching happens implicitly via the account email, which tells the agent no identifier argument is needed.

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 plus precise scope: up to 5 distinct shipping addresses from past orders, matched by account email, newest first. This clearly separates it from get_shipping_options (available methods) and set_shipping_address (the write counterpart).

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?

Gives an explicit when: for a returning buyer, call before asking for an address. It also names the downstream step (pass the pick to set_shipping_address) and the when-not/alternative path for an empty list (ask the human).

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