send_email

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

No annotations are provided, so the description must carry the full burden of behavioral disclosure. It only mentions threading support, but fails to disclose potential side effects, error behavior, authentication needs, or output structure. For a mutation tool like send_email, this is a significant gap.

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 extremely concise, consisting of two short sentences with no extraneous information. It is front-loaded with the core purpose and efficiently conveys the key additional feature (threading support).

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 complexity (11 parameters, 4 required), the description is minimal. While the existence of an output schema reduces the burden for explaining return values, the description omits important contextual cues about account setup, attachment handling, or when to use this tool in conjunction with others like 'list_available_accounts'. It is adequate but not comprehensive.

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 100%, so the baseline is 3. The description adds meaning to the 'in_reply_to' parameter by explaining its role in threading, but does not enhance understanding of other parameters beyond what the schema already provides.

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's purpose: 'Send an email using the specified account.' This is a specific verb+resource pairing that distinguishes it from sibling tools like delete_emails or list_emails_metadata. The mention of threading support adds clarity.

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 provides a usage hint for replying to emails via 'in_reply_to' but does not explicitly state when to use this tool versus alternatives, nor does it mention prerequisites or exclusions. The context is implied but not detailed.

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