send_dm

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

No annotations are provided, and the description only states the basic action. It does not disclose potential side effects (like opening a DM channel), required permissions, rate limits, or error behavior, which is a significant gap for a mutating 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 a single, front-loaded sentence with no unnecessary words. It precisely conveys the core action in an efficient format.

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?

The tool is simple and the schema covers parameters, but the lack of behavioral context (e.g., success/failure behavior, permission requirements) and the absence of an output schema leave some gaps. It is adequate but not fully complete for an agent selecting and invoking the 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?

The input schema already provides descriptions for both user_id and content with 100% coverage. The description adds minimal extra meaning beyond reinforcing that the message goes to a user by ID, so it meets the baseline but does not exceed it.

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 uses the specific verb 'Send' and resource 'direct message to a user by their ID', clearly identifying the tool's function. It distinguishes from sibling tools like send_message and send_embed by focusing on the DM use case.

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 phrase 'direct message to a user' provides clear context for when to use this tool. However, it does not explicitly name alternatives or state when not to use it, so it does not fully meet the level of explicit when/when-not guidance.

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