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

Annotations already establish that this is a non-destructive write in a closed world. The description adds one useful behavioral fact beyond that: a follow-up email is sent when the area becomes serviceable. It still doesn't say what gets stored, how duplicate signups are handled, or what a success response contains.

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?

A single compact sentence with no filler, and the purpose comes first. The phrasing 'address we don't pick up at yet' is slightly awkward and forces a second read, which costs it a point.

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?

This is a five-required-parameter mutation with no output schema. The description covers intent and the deferred-notification behavior, but it never says what the agent gets back or how failures are surfaced. That leaves an agent unable to predict the outcome of a call.

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 only 60%. The email and city properties have no descriptions at all, yet the description addresses only 'email' and gestures vaguely at 'address'. It adds no format, normalization, or validation guidance to compensate for the two undocumented fields.

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 gives a concrete verb-and-resource pair: it captures an email tied to an address that is not yet serviced, and promises a notification when service arrives. That is clearly distinct from siblings like add_address or start_subscription. It stops short of naming any sibling, so the agent has to infer the boundary itself.

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 precondition is implied: you use this only for an address we don't pick up at yet. The description never says so explicitly, though, and it doesn't tell the agent whether to check_address first or whether an already-served address is rejected here. The guidance is present but only by inference.

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