set_signature

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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=true; the description adds genuinely useful behaviour beyond that: only the signature is mutated, no mail is dispatched as a side effect, and an empty string is the documented deletion path. It stops short of stating persistence scope (account-level vs alias-level) or permission requirements.

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?

Three short sentences, each carrying distinct information (action, side-effect boundary, clearing semantics), with the core action front-loaded. No filler or restatement of the tool name.

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 three-parameter mutation tool with annotations present and no output schema, this covers the essentials an agent needs: what changes, what does not happen, and how to clear the value. The only real gap is prerequisite/authorization context for the target account.

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 baseline is 3, but the description earns extra credit by explaining two non-obvious parameter semantics: HTML is accepted for 'signature', and an empty value means removal rather than a no-op. It says nothing about the optional 'send_as' alias parameter, which is left entirely to the schema.

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?

States a specific verb and resource ('Sets the email signature of an account') plus a format hint (HTML allowed). No sibling tool touches signatures, so an agent can identify it unambiguously from the name-plus-description pair alone.

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 rather than stated: the agent infers this is the write path for signature configuration, and 'it sends nothing' implicitly contrasts it with send-oriented workflows. There is no explicit when-to-use/when-not guidance and no prerequisite such as the account needing to be connected first (connect_account/check_accounts exist as siblings).

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