set_identity

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It usefully reveals that changes apply automatically to every outgoing message, but it does not explain permission requirements, whether fields can be cleared with null, or how the two signature formats interact.

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 description is a single, tightly worded sentence that front-loads the core action and its key effect. There is no filler or redundant information.

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 relatively simple tool, the description captures the main purpose and outcome, but it omits guidance on optional parameter semantics and usage boundaries. Since there is no output schema and no annotations, a bit more contextual detail would be needed for fully confident invocation.

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 40%, and the description only loosely maps to the parameters by mentioning 'display name and signature'. It does not clarify signatureHtml versus signatureText, the meaning of null, or constraints on the optional fields, leaving significant semantic gaps.

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 uses a specific verb ('Set') with a clear resource ('a mailbox's display name and signature') and states the resulting behavior ('applied automatically to every outgoing message'). This clearly distinguishes it from sibling tools like get_identity and set_vacation.

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 description implies when to use the tool—when you need to configure a mailbox's display name or signature—but it does not explicitly state when to prefer it over alternatives or mention any exclusions. The sibling get_identity makes the read/write distinction inferable, but not explicit.

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