message_send

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

Without annotations, the description carries the burden. It explains the async nature ('recipient will see it when they call message_inbox') and the effect (message delivered to inbox). No contradictions; sufficient for this simple write operation.

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?

Concise at ~100 words, with a clear structure: one-sentence summary, then usage guidance, then parameter breakdown. No redundant or missing 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?

For a simple tool with 100% schema coverage and an output schema, the description is complete. It covers purpose, usage, parameters, and effects, leaving no gaps for the agent to guess.

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 baseline is 3. The description adds no new meaning beyond what the schema already provides for 'to', 'body', and 'subject'. The description of 'to' values (broadcast, project:<name>) also appears in 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 tool sends a message to another agent's inbox, providing a specific verb and resource. It distinguishes from siblings like message_inbox by explaining the recipient sees it when they call that tool.

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?

Explicitly lists use cases (delegating work, sharing findings, etc.) and contrasts with how the recipient retrieves the message via message_inbox. Lacks explicit 'when not to use' but context is clear.

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