Update Mailbox Identity

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

The description is minimal, stating only that it changes sender identity details. While annotations provide idempotentHint=true and readOnlyHint=false, the description doesn't disclose side effects, permissions, or update behavior (e.g., partial vs full replacement). It does not contradict annotations.

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 concise and front-loaded with two sentences that earn their place, containing no redundant or unnecessary 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?

Given the tool's simplicity (4 optional params, output schema exists, annotations present), the description covers the core purpose. Minor gap: no guidance on relationship to mailbox_get_identity or identity management workflow, but sufficient for basic use.

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?

The input schema has 100% description coverage with clear parameter documentation (e.g., 'Send null or an empty string to clear it.'). The description adds no additional semantic value beyond the schema, meeting the baseline expectation.

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 clearly states the tool is for changing sender identity details and explicitly distinguishes it from one-off message composition, providing a specific verb-resource pairing that differentiates it from siblings like sending_send_email.

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 gives explicit guidance on when to use ('only when the user explicitly asks') and what not to use for ('one-off message composition'), but does not mention alternative tools or when not to use beyond the given exclusion.

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