Send direct message

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

Annotations only provide readOnly=false, destructive=false. Description adds that the message comes from the bot (not user) and explains graceful failure, which are useful beyond 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?

Two sentences with no redundancy. First sentence states purpose, second adds key behavioral detail. Efficient and front-loaded.

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 send operation with no output schema, description covers purpose, failure condition, and sender identity. Could mention content length but schema covers that.

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 67%, so description adds value for 'user' and 'guild' parameters (e.g., 'Member name or user ID'). 'content' lacks description but schema has min/max length. Adequate.

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?

Clearly states the verb 'send', resource 'direct message', and scope 'from bot to member in same server'. Distinguishes from siblings like send_message and send_webhook_message.

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?

Explicitly mentions graceful failure when recipient has DMs closed, giving a condition. Does not directly compare to alternatives but context is clear.

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