send_message

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

No annotations are provided, leaving the description to bear the full burden of behavioral disclosure. The description only states the action without mentioning side effects, return values, errors, or requirements such as permissions or conversation state. This significant gap limits an agent's ability to anticipate the tool's 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 a single, concise sentence that directly communicates the tool's purpose without unnecessary words or repetition. It is front-loaded and efficient.

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 simplicity of the tool (2 parameters, no output schema) and complete schema coverage, the description is minimally adequate. However, it lacks information about return values, error handling, or preconditions beyond 'existing conversation', and no annotations supplement this, leaving moderate gaps.

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 fully describes both parameters (message and conversation_id) with clear descriptions, achieving 100% schema coverage. The tool description adds no additional parameter information, so the baseline score of 3 is appropriate.

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 tool's action: sending a message within an existing conversation. It uses a specific verb ('send') and resource ('message in conversation'), and distinctively differentiates from sibling tools like start_conversation or get_conversation.

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 by specifying 'in an existing conversation', which implies when the tool should be used (only after a conversation exists). However, it does not explicitly mention alternatives for new conversations or any exclusions, so it falls short of a 5.

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