create_direct_message

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

Annotations indicate this is a non-read-only, non-destructive operation (readOnlyHint: false, destructiveHint: false), which the description aligns with by implying a creation action ('Send'). The description adds some behavioral context by specifying the requirement for attachments, but does not elaborate on permissions, rate limits, or other side effects beyond what annotations provide.

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 brief and front-loaded, consisting of two sentences that directly state the tool's purpose and a key requirement. There is no unnecessary elaboration, making it efficient, though it could be slightly more structured to better highlight critical information.

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?

Given the tool's complexity (6 parameters, nested objects) and lack of an output schema, the description is somewhat incomplete. It covers the basic action and attachment requirement but does not address error conditions, response format, or interactions with sibling tools, leaving gaps for the agent to navigate.

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?

With a high schema description coverage of 83%, the input schema already documents most parameters well. The description adds minimal value by hinting at the need for 'transcript or link attachments,' which loosely relates to the 'transcript' and 'links' parameters but does not provide additional semantics or clarify usage 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 action ('Send a Direct Message') and target ('to a User or a Group of Users'), which is specific and actionable. However, it does not explicitly differentiate from sibling tools like 'create_conversation_message' or 'create_voicememo_message', leaving some ambiguity about when to choose this tool over alternatives.

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 minimal guidance by stating 'you must provide transcript or link attachments,' but this is a requirement rather than contextual advice. It offers no explicit when-to-use or when-not-to-use instructions, nor does it mention alternatives among sibling tools, leaving the agent to infer usage scenarios.

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