list_email_senders

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

With no annotations, the description discloses the list operation and mentions that senders belong to verified domains. It is clear and consistent, though it omits potential details like pagination or ordering.

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?

Two sentences, each adding value: first states the main action, second clarifies the purpose. No wasted words.

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 no parameters and an output schema, the description adequately covers what the tool does and its context (verified domains, use in send_email). No gaps.

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?

There are no parameters, so baseline is 4. The description adds no parameter information as none exist.

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 states the action 'list' and resource 'registered sender addresses' clearly, and explains their use in the 'from_email' field of send_email. This distinguishes it from sibling tool list_email_domains which lists domains.

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 usage context (for obtaining valid from addresses for send_email) but does not explicitly say when not to use this tool or compare with alternatives like list_email_domains.

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