Send direct message

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

Annotations already indicate non-read-only and non-destructive, and the description adds valuable context: it fails gracefully when the recipient has DMs closed, and the message always comes from the bot, never a user account. This goes beyond the structured annotations and clarifies important operational behavior.

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 two sentences, front-loaded with the core purpose, followed by two concise behavioral notes. Every sentence adds value, with no redundancy or fluff.

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 DM tool with annotations and partial schema documentation, the description covers purpose, recipient constraint, failure mode, and message source. No output schema exists, so return values need not be explained. The description is complete and sufficient for an agent to select and use the tool 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 67% (user and guild documented, content not). The description adds meaning by specifying the user must share a server with the bot, which reinforces the user parameter. Content is self-explanatory despite lacking schema documentation. Moderate value added, not fully compensating for the coverage gap.

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 action ('Send a direct message') and specifies the recipient ('a member who shares a server with it') and source ('from the bot'), which distinguishes it from channel-sending tools like send_message. The verb+resource structure is explicit and unambiguous.

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 description provides clear context on when to use the tool: for direct messages to a member sharing a server, and notes a prerequisite (shared server) and failure behavior (graceful when DMs closed). However, it does not explicitly mention alternatives or when not to use it, though the differentiation from send_message is implied.

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