reply_email

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

With no annotations, the description fully discloses behavior: it fetches headers, constructs threading, determines recipients (Reply-To or From, including others for reply_all), and saves to Sent by default. This satisfies the transparency burden, though it doesn't cover error cases or auth requirements.

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 well-structured with purposeful line breaks, front-loaded purpose, and concise bullet points for arguments. Every sentence contributes meaning without redundancy.

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 tool's operation thoroughly given 7 parameters and no output schema. It lacks mention of return value or error handling, but overall provides sufficient context for an agent to use the tool effectively.

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 0%, so the description compensates by explaining each parameter: body, html, reply_all, attachments, save_to_sent are described with clear semantics. Folder and email_id are minimally explained but adequate. This adds significant value over the bare schema.

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 'Reply to an email with correct threading headers', specifying the verb (reply) and resource (email). It distinguishes from sibling tools like forward_email and send_email by detailing threading behavior (RFC 5322).

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 for replying rather than forwarding or sending new emails through its threading details, but lacks explicit when-to-use or alternatives. It does not state explicit exclusions, yet the context is clear enough for an agent to differentiate.

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