gmail_set_signature

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

With no annotations, the description carries the burden and does disclose the key traits: this is a mutation, it only affects mobile-originated mail, and an empty string removes the signature. It says nothing about persistence, which account/profile is modified, or whether the change propagates to existing drafts.

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?

One short sentence, front-loaded with the action and scoped resource, with the removal case in a compact parenthetical. Nothing extraneous.

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 single-parameter mutation with no output schema, the description covers scope (mobile only) and the clearing case, which is what an agent needs to call it correctly. Only the target account and persistence behavior are left unstated, both minor here.

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 schema already states 'any Unicode, newlines allowed; empty string = no mobile signature'. The description's '("" removes it)' restates that fact rather than adding new syntax or format detail, so baseline 3 applies.

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?

Names a specific verb+resource ('Set the mobile signature') and narrows the scope to signatures on mail sent from the phone, which separates it operationally from the desktop/web signature. It doesn't explicitly name the read-side sibling gmail_signature, so differentiation is implicit rather than stated.

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: the parenthetical shows how to clear the signature, which hints at when the tool applies, but there is no statement of prerequisites (e.g., which account), no when-not guidance, and no reference to gmail_signature for reading the current value.

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