send_dm

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively communicates critical operational constraints: the required permission scope and the 24-hour reply window, which are essential for correct usage. However, it lacks details on rate limits, error conditions, or response format.

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 extremely concise and front-loaded with the core purpose, followed by essential constraints. Every sentence earns its place by providing critical information without any 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?

Given the tool's complexity (a mutation operation with no annotations and no output schema), the description is reasonably complete. It covers the action, prerequisites, and a key behavioral constraint. However, it could be more complete by mentioning potential error cases or the expected response format.

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 schema description coverage is 100%, with clear parameter descriptions in the schema. The tool description does not add any additional semantic context about the parameters beyond what is already documented in the schema, such as explaining the format of 'recipient_id' or providing examples for 'message'.

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 specific action ('Send Instagram direct message') and resource ('direct message'), distinguishing it from siblings like 'post_comment' or 'reply_to_comment' which involve public interactions rather than private messaging.

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 about prerequisites ('Requires instagram_manage_messages with Advanced Access') and a temporal constraint ('Can only reply within 24 hours'), but does not explicitly state when to use this tool versus alternatives like 'get_conversation_messages' or 'get_conversations' for reading messages.

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