send_dm

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

No annotations are provided, so the description carries the transparency burden. It discloses the numeric id requirement and auto-resolution behavior, but does not mention what happens on failure, rate limits, or whether the message is sent immediately. This is adequate but not fully transparent.

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 sentences, front-loaded with the action. Every sentence adds useful information: what the tool does, the recipient format, and an important prerequisite. No unnecessary detail.

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?

For a simple tool with two required parameters, the description is nearly complete. It explains how to specify the recipient and what to send. Without an output schema, it does not detail the response, but this is a minor gap for a straightforward send action.

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?

The input schema already documents both parameters at 100% coverage. The description adds semantic value by explaining that recipient_id must be a numeric id and instructing the agent to resolve @handles with get_user first. This goes beyond the 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 the tool sends a direct message to a user, with a specific verb and resource. It distinguishes from siblings like post_tweet and get_dm_inbox by focusing on DMs and includes a key detail about resolving handles.

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?

Provides clear context: requires a numeric id and explicitly instructs to use get_user to resolve a @handle. Also notes that the user's own id is auto-resolved. Does not explicitly exclude alternatives, but the guidance is sufficient for the primary use case.

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