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

Annotations already declare it read-only, idempotent, non-destructive and closed-world. Beyond that, the description adds genuinely useful process behavior: the sendAs PATCH applies only to new mail, Outlook is copy-paste-only with no directory sync, and the Chrome extension auto-updates and covers replies but requires human signup.

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?

It is a single dense sentence with stacked parentheticals and an odd 'honestly:' opener; every clause carries content but the structure is rambling rather than cleanly front-loaded.

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 low-complexity, single-enum, read-only info tool with no output schema, the description conveys enough about what each client's result will cover. Safety is covered by annotations, so no major gap remains.

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%, so the enum is already documented, but the description adds meaning by distinguishing 'Gmail web' from 'Gmail mobile' and characterizing each client's install path, helping the agent pick the right enum value.

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 — install steps for getting a signature into a mail client — and ties it to the sibling create_signature as the source of the signature. It is not a tautology, though the front-loaded intent is somewhat buried under per-client detail rather than stated as a crisp verb+resource.

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 only implied: you call this after create_signature to learn how to install the signature into a given client. There is no explicit when-to-use/when-not statement or named alternative, though the client enumeration and the Chrome-extension signup note gesture at context.

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