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

The annotations already mark this as a read-only operation, and the description adds useful behavioral context by stating the authentication requirement and account prerequisite. It does not describe return values, but an output schema exists, so that omission is acceptable.

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 core purpose is front-loaded, and the access instructions are separated into a second block. The sentence about `start_login` opening the session is slightly awkward, but overall there is little wasted text.

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 one-parameter read-status tool with an output schema and read-only annotation, the description covers the key missing context: authentication and account requirements. It could be more explicit about where the session ID comes from, but it is otherwise sufficient.

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% for the single `session_id` parameter, so the schema already carries the parameter semantics. The description mentions checking by session ID, but adds no syntax, format, or origin details beyond what the schema provides.

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 a specific verb and resource: checking the status of an in-progress email addition by session ID. It is easy to distinguish from general email listing, but it does not explicitly mention the starting sibling `start_add_email` or contrast itself with `get_add_phone_status`.

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 provides clear access context: a Proof account is needed, and the agent must authenticate or use `start_login`. However, it does not explicitly say this tool should be called after `start_add_email`, nor does it explain polling behavior or alternatives, leaving usage partly implied.

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