send_message

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

Beyond the annotations (read-only=false, idempotent=false, destructive=false), the description reveals real side effects: the message is emailed to every recipient, replies inherit the subject thread, and a confirm flag is required. This gives an agent an accurate model of send behavior without contradicting the 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?

Three dense sentences front-load the core action and recipients, then explain email behavior, reply mechanics, and the confirmation requirement. No filler or redundant restating of the tool name.

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 6-parameter tool with full schema coverage and safety annotations, the description plus schema provides everything an agent needs to invoke it correctly: recipient scope, sending mechanics, reply behavior, and confirmation. The absence of an output schema is acceptable because the description does not need to document return values for a blocking send action.

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 already documents all six parameters at 100% coverage, so the baseline is 3. The description adds useful semantics by explaining that reply_to_message_id creates an in-thread reply with inherited subject and reinforces that confirm must be true; it does not need to re-document body or origin.

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 names a specific action and resource: sending a message to the vendor and workspace members through the HoneyBook portal. The composer comparison and email behavior make it easy to distinguish from read-oriented siblings like list_messages, get_message, and mark_messages_seen.

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?

It clearly states the tool's context (sending through HoneyBook as the Activity tab does) and when to use the reply parameter: 'Pass reply_to_message_id to reply in-thread'. It does not explicitly name alternatives or exclusions, but none of the sibling tools perform the same send operation, so the guidance is sufficient.

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