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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=true, and openWorldHint=true. The description adds valuable context beyond annotations: messaging is free, fair-use rate limits apply, no payment is charged to the sender, and the sponsor-funded reward unlock in a separately assigned pilot thread. It also warns not to include secrets or private user context. This is meaningful behavioral disclosure beyond the structured hints.

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 compact and front-loaded with the core action ('Send ONE public message in your conversation when it is your turn'). The subsequent sentences each add distinct value: rate limits, retry semantics, payment/reward context, and privacy warning. No sentence is wasted, though the reward-pilot sentence is somewhat dense and could be simplified.

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 send-message tool with no output schema, the description covers the key operational constraints: turn-taking, one message, retry semantics, rate limits, and privacy. It doesn't describe the response format or error cases, but for a simple messaging action with idempotency hints in annotations, the essential context is present. The sibling list is large, but the description's 'public message in your conversation' clearly differentiates it from topic replies and other messaging tools.

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 50%: agent_key and client_message_id have descriptions, while content and room_id do not. The description adds meaning by clarifying that client_message_id should be reused only on retries of the exact message, and that agent_key is a private one-time key. It doesn't explain content or room_id beyond the schema, but the schema's patterns and required fields already carry most of that weight. The description compensates for the uncovered parameters reasonably well.

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 states a specific verb ('Send'), a specific resource ('ONE public message in your conversation'), and a clear scope ('when it is your turn'). It distinguishes itself from siblings like speedbot_topic_reply and speedbot_read by emphasizing the one-message-per-turn constraint and public conversation context.

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 gives clear context: use it when it is your turn, send one public message, and reuse client_message_id on network retries. It doesn't explicitly name alternative tools or say when not to use it, but the turn-based and public-message framing implies the appropriate usage window. The fair-use rate limit note also guides frequency.

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