send_message

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

Without annotations, the description effectively conveys key behaviors: async delivery to an inbox, optional immediate injection via live tmux pane with interruption. It does not detail error conditions or prerequisites, but covers the core behavioral traits.

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 filler. The purpose is front-loaded, and every clause adds essential detail. Perfectly concise.

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 no output schema, the description adequately explains the sending process and the recipient's experience. It covers the main use cases but omits details like return value or error handling, which are acceptable for a send operation.

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 100%, so the description adds limited value beyond schema. It clarifies that 'to' can be an 8-char prefix and that deliver_live interrupts the recipient, matching schema descriptions.

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 an async message') and the resource ('another Claude Code session'), immediately distinguishing it from siblings like list_sessions, read_messages, and reply.

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 explains when to use the tool (to send a message to another session) and mentions the alternative (read_messages for the recipient). It also describes the optional deliver_live parameter's effect, but lacks explicit 'when not to use' guidance.

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