send_email_reply

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

The description labels the action as [mutation] and notes the confirmation requirement, but does not elaborate on side effects like immediate sending, rate limits, or required permissions. With no annotations, more detail would be beneficial.

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 very concise, front-loading the purpose and including the mutation flag and confirmation requirement in a single efficient sentence.

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?

The description covers the core behavior and confirmation requirement, but lacks details on return values, error conditions, and integration with other email tools. Given no output schema, more context on outcomes would improve completeness.

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 coverage is 100% with descriptions. The description adds meaning by clarifying that thread_id=0 indicates a new email and that to/subject are obligatory for new emails, which is not enforced in the schema. It also highlights the confirm parameter's role.

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 sends a reply to an existing email thread or composes a new email, using specific verbs and resources. It distinguishes from siblings like generate_email_draft, which is for drafting only.

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 requires passing confirm=true to execute, which is a key usage condition. However, it does not provide guidance on when to use this tool vs alternatives (e.g., generate_email_draft) or prerequisites like having an email account.

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