send_message

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

Annotations cover the safety profile (write, non-destructive, non-idempotent), and the description adds genuine behavioral context beyond them: the output is a draft held for review and it always gates on approve_draft regardless of mode. It stops short of explaining the non-idempotency implication or what state the draft lands in.

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?

Two tight sentences, front-loaded with the core action and constraint. The second sentence earns its place by disclosing the approval gate, though the 'draft_mode' clause adds confusion rather than value.

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, and the approval-gate behavior is covered. But with three undocumented required parameters and a misleading 'draft_mode' mention, the definition is only minimally complete for an agent to invoke it correctly.

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% and none of the three parameters are documented. The description adds only one hint ('one handle or conversation', suggesting recipient accepts either), and does not explain account or text. Worse, it cites 'draft_mode', a parameter that does not exist, which can mislead the agent.

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 states a specific verb+resource ('prepare a reviewed DM draft') and, importantly, disambiguates from the tool's own name 'send_message' by clarifying it drafts rather than sends. It is distinguishable from siblings like approve_draft, prepare_reply, and queue_post, though it does not explicitly name them.

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 establishes a workflow prerequisite ('Always requires approve_draft'), which routes the agent to a specific sibling, but gives no when-to-use/when-not guidance or contrast with prepare_reply/queue_post. The reference to 'draft_mode' is confusing because no such parameter exists in the schema, weakening the guidance.

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