draft_reply

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

With no annotations provided, the description carries the full burden. It discloses key behaviors: automatic derivation of recipient, subject, and threading headers; the effect of 'reply_all' on CC recipients; and the return format. However, it lacks details on permissions, error handling, or rate limits, which are important 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 front-loaded with the core purpose, followed by key behaviors and return values in two efficient sentences. Every sentence adds value without redundancy, making it easy to parse and understand quickly.

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 moderate complexity (mutation with 4 parameters) and no annotations or output schema, the description does a good job covering purpose, usage, and return format. However, it could improve by addressing potential errors or side effects, which would enhance completeness for an unannotated mutation tool.

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 schema already documents all parameters thoroughly. The description adds minimal value beyond the schema, mentioning 'reply_all' and 'mailbox' briefly but not providing additional context or examples. This meets the baseline for high schema coverage.

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 specific action ('Create a reply draft to an existing email') and distinguishes it from sibling tools like 'create_draft' by specifying it's for replying to an existing email with automatic derivation of metadata. It uses precise verbs and identifies the resource (reply draft).

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 context for when to use this tool (replying to an existing email) and implicitly differentiates it from 'create_draft' (which likely creates drafts from scratch). However, it does not explicitly state when not to use it or mention alternatives like 'update_draft' for modifying existing drafts, which could be helpful.

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