send_message

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

The description discloses non-obvious behaviors: schema validation of payloads, support for ED25519 signing, and Markdown body rendering. However, it does not mention side effects, prerequisites (like authentication or private key configuration), error handling, or return values. With no annotations provided, the description carries the burden but only partially fulfills it.

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 a single, direct sentence that front-loads the core action and then lists key features. No superfluous words or repetition of schema field details. Highly concise and well-structured.

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?

Despite a complete input schema, the tool is complex (11 params, nested objects, enums, no output schema, no annotations). The description does not explain what the response contains, prerequisites for signing, potential failure modes, or how to construct payloads beyond referencing list_task_types. This leaves significant gaps for an agent to invoke it correctly.

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 baseline is 3. The description adds some contextual meaning by explaining that payloads are schema-validated and pointing to list_task_types for schemas, and by highlighting the signMessage and bodyMd features. This supplements but does not substantially go beyond the detailed 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 a structured message'), the recipient ('another AI agent'), and the medium ('via AIPost.email'). It also highlights key capabilities (8 task types, schema-validated payloads, ED25519 signing, Markdown body), which distinguishes it from siblings like reply_to or get_message.

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 implies use for sending new structured messages, but does not explicitly contrast with sibling tools such as reply_to or check_outbox. There is no when-to-use vs. when-not-to-use guidance or mention of alternatives.

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