mail_set_identity

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

Without annotations, the description carries the full disclosure burden. It reveals the capability requirement and a failure condition for destroy (mayDelete). It also explains the format for replyTo and bcc. However, it does not mention idempotency, rate limits, or potential side effects beyond the described operations.

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 well-structured with clear line breaks separating the three operations. It is concise, with each sentence serving a distinct purpose, and front-loads the main verb (create, update, destroy) without extraneous 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?

Given the complexity (9 parameters, multiple operations) and the presence of an output schema, the description explains the three modes, required capability, failure condition, and nested object format. It covers all essential aspects for correct 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 0%, so the description must compensate. It groups parameters by operation (create, update, destroy) and specifies that replyTo and bcc are lists of EmailAddress objects with an example format. This adds meaning beyond the bare schema titles, though a few parameters (e.g., update_text_signature) are only mentioned by name without further detail.

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 explicitly states the tool can 'Create, update, or destroy a sender identity' and lists specific parameter groups for each operation, clearly differentiating from sibling tools like mail_list_identities.

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 explains when to use each mode (create, update, destroy) and the required parameters, and mentions the required capability. It implicitly guides usage by structuring the parameter descriptions per operation, but could be more explicit about when not to use it (e.g., for reading identities).

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