send_email

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

No annotations are provided, so the description carries full burden. It states 'send immediately' but does not disclose behavioral traits like error handling, rate limits, delivery guarantees, or irreversibility. While it lists parameters, it omits important behavioral context for a mutation tool.

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 mostly concise with a short opening sentence and a structured parameter list. However, the parameter list is slightly verbose with default values shown, and the format could be more compact. Still, it is efficient and front-loaded.

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 9 parameters (2 required), no annotations, and an output schema present, the description covers parameter semantics well but lacks usage context, errors, or return value details. It is complete enough for basic use but could benefit from mentioning threading behavior and error conditions.

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?

With 0% schema coverage, the description adds full meaning: it explains each parameter's purpose and format (e.g., 'comma-separated' for to/cc/bcc, 'use list_identities to see options' for identity_id). This goes far beyond the schema's minimal type information.

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?

Description clearly states the tool 'Compose and send an email immediately.' The verb 'send' and resource 'email' are specific, and it distinguishes from sibling tools like create_draft (which only creates a draft) and reply_email (which is a specific reply action).

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 immediate sending but lacks explicit guidance on when to use this versus alternatives such as create_draft or reply_email. No prerequisites or exclusions are provided, so usage context is only implied.

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