send_message

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

The description discloses that the message content is sealed until published (via publish_channel), while metadata (who, how many, recency) is visible. It also mentions that the tool is 'Free'. It doesn't mention error handling or rate limits, but given no annotations, it provides significant behavioral context.

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, well-organized, and front-loaded with purpose. It uses clear language and a logical flow, without unnecessary 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 the main functionality and behavioral aspects, but it does not mention the return value or response format. Since there is no output schema, it would be helpful to state what the tool returns (e.g., message ID or success). It also doesn't mention any prerequisites beyond the parameters, though the required api_key is in the schema. Given the moderate complexity, it's slightly incomplete.

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 description adds meaning beyond the schema by explaining the relationship between to_kingdom_ids and channel_id (OR), and the semantics of multi-party vs 1:1. It also explains reply_to. Even though the schema has parameter descriptions, the description clarifies usage with concrete examples.

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 function: sending private messages. It distinguishes between two modes: direct to kingdoms (to_kingdom_ids) and to an existing channel (channel_id). It also mentions reply_to for threading. It is specific and unambiguous.

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 usage instructions by explaining when to use to_kingdom_ids vs channel_id, and what reply_to does. It doesn't explicitly compare with sibling tools, but the function is clearly distinct, offering enough guidance for an agent to know how to call it.

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