dm_message_send

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

Adds key behavior beyond annotations: 'The message is queued and delivered asynchronously (returns status: pending).' Also clarifies platform-specific behaviors (tag for Facebook/Instagram, reply fields for Telegram). No contradiction with annotations.

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?

Three sentences, front-loaded with the main action, each sentence serves a purpose: stating the action, giving key constraint, explaining async and platform details. No wasted words.

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?

Covers all major aspects: parameter constraints, async behavior, platform differences, and required tag. Without an output schema, it mentions the pending status. Could be enhanced with error handling details, but is adequate for a messaging 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 coverage is 100%, so baseline is 3. The description adds value by making the exclusivity of body and media explicit ('not both') and reinforcing platform restrictions, which improves clarity beyond the schema's individual descriptions.

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 starts with 'Send an outbound direct message,' providing a specific verb and resource. It distinguishes this tool from siblings like dm_message_edit by emphasizing outbound sending and async delivery.

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?

Clearly states when to use body vs media, tag requirement for 24h window, and platform-specific parameters. While it doesn't explicitly name sibling tools, the constraints are clear enough for an agent to decide when to use this tool.

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