send_message

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

With no annotations provided, the description fully carries the burden of behavioral disclosure. It reveals that messages are persisted to disk, survive restarts, and use JSONL format for concurrent-write safety, adding critical context beyond the schema.

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 concise (three short paragraphs) and well-structured, with each sentence serving a purpose: stating the action, usage context, channel conventions, and persistence details. No 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?

The description covers channel usage, persistence, and concurrency safety. However, since there is no output schema, it does not mention what the tool returns (e.g., success confirmation), which is a minor gap for completeness.

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 value by explaining channel conventions (broadcast vs targeted) and noting payload can be any JSON-serializable value, enhancing parameter understanding beyond what the schema provides.

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 a channel for inter-agent communication, specifying the verb 'send' and resource 'channel'. It also distinguishes from siblings like get_messages (receiving) and signal_step_complete (different purpose) by focusing on sending structured data between pipeline steps or agents.

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 explicit guidance on when to use this tool ('between pipeline steps or between any agents') and details channel conventions for broadcast vs targeted messaging. While it doesn't explicitly mention when not to use it or compare to alternatives, the context is clear enough for an agent to decide.

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