Send fmsg draft

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

Goes well beyond the destructiveHint/non-idempotent annotations by stating the message becomes immutable once sent (cannot be edited or recalled) and describing refusal handling: the host's reason is returned verbatim and the message stays a draft. These are exactly the behavioral traits an agent needs before committing an irreversible action.

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?

Four tight sentences, front-loaded with the action and its precondition, then the irreversible consequence, then authorization scope, then failure behavior. No filler, no repetition of the schema.

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?

An output schema exists, so return values need no explanation; the description still covers the prerequisite, the irreversibility, the authorization boundary and error semantics. Nothing an agent needs before calling this one-param write tool is missing.

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% and the single 'id' parameter is fully documented ('the draft to send', numeric pattern). The description adds no syntax or constraint detail beyond that, so the baseline 3 applies.

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?

States a specific verb (send) and resource (a draft made with create_draft), and clarifies that attachments go along and it happens immediately. It is clearly distinguishable from create_draft (which makes the draft) and send_message (which composes/sends new mail).

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?

It names the prerequisite tool (create_draft) and sets a scope condition: send only within the user's requested task or authorized automation. It does not explicitly contrast with send_message or reply, so the agent must infer the alternative routing, but the when-to-use context is clear.

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