draft_reply

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

No annotations are provided, so the description carries the full burden. It states the tool returns a draft template and does not send, which discloses its non-destructive nature. However, it does not mention if the draft is saved or just returned, nor any required permissions or rate limits. The behavioral traits are adequately but not richly disclosed.

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 sentences that immediately convey purpose and critical usage constraint. Every word earns its place, and it is front-loaded with the essential action.

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 has 5 parameters and no output schema, the description is fairly complete. It explains the return value (template with headers and quoted message) and the non-sending behavior. However, it could be improved by specifying the template format (e.g., plain text or HTML) or noting that it does not modify the original email.

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 value by noting that the body is 'prepended to quoted original'—a detail not in the schema. However, it does not elaborate on each parameter beyond the schema's own descriptions. This is acceptable but not exceptional.

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 'Generate a reply draft for an email' and specifies it returns a template with headers and quoted original message. It distinctly separates this from sending by explicitly saying 'Does NOT send — use send_email to send after user reviews.' This is a specific verb+resource and distinguishes from a sibling tool.

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 clear guidance: use this tool to create a draft and then use send_email for sending. It implies a workflow. However, it does not contrast with compose_email (another sibling for creating new emails), which could help the agent choose more precisely. Still, the explicit 'use send_email' is strong.

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