send_message

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

With no annotations, the description carries the full burden, and it does disclose a genuinely useful trait: encryption happens client-side and the relay never sees plaintext. However, it omits auth requirements, whether the message is persisted, idempotency/retry behavior, and failure modes, which are material for a write/relay tool.

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 tight sentences with the security-relevant fact front-loaded and zero filler. Nothing could be cut without losing 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 3-param mutation tool with no annotations, no output schema, and 0% schema coverage, the description covers the security model well but leaves the operational model thin: no auth/prerequisite info, no confirmation of what the call returns, and no parameter semantics.

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 description coverage is 0% for all three required parameters, so the description must compensate and does not. It hints at 'room' and 'message' but never explains room_id format, what counterparty_id identifies (an agent id?), or any constraint on text.

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 gives a specific verb+resource: it encrypts a message and relays it into a room, and names the crypto primitives (X25519 + ChaCha20-Poly1305). That is clearly distinct from siblings like fetch_messages or open_room, though it never names the counterpart operation explicitly.

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?

There is no when-to-use guidance, no prerequisites (e.g., agent must be registered, room must be open, counterparty must exist), and no reference to alternatives such as file_receipt for non-message payloads. Usage is only implied by the verb 'relay'.

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