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

readOnlyHint=true already tells the agent this is a safe read, lowering the bar. The description adds one piece of real context beyond that ('including verification details') and names the underlying endpoint, but says nothing about error behavior for unknown ids or whether the lookup costs an API call.

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?

Two short sentences, front-loaded with the action and resource, with the endpoint reference as trailing detail. Nothing is padded or redundant.

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?

No output schema exists, and the description partially compensates by noting that verification details are included in the response. For a one-parameter read tool the definition is nearly complete; only the failure mode for an invalid id is unaddressed.

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 coverage is 100% and the single 'id' parameter is documented with an example prefix ('adr_...'), so the schema already carries the semantics. The description only restates 'by id' and adds nothing about format or validity, making 3 the correct baseline.

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?

Specific verb ('Retrieve') plus resource and scope ('a single address by id'), which cleanly distinguishes it from sibling easypost_list_addresses. The parenthetical 'including verification details' further narrows what this returns.

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?

Usage is implied by 'by id' — use it when you already hold an address id — but the description never states when to prefer this over easypost_list_addresses or easypost_verify_address, both of which are plausible alternatives. No exclusions or prerequisites are given.

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