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

There are no annotations to indicate side effects, and the description only mentions returning status and reply. It does not explicitly state that the tool is read-only or non-destructive, nor does it disclose potential error conditions or limitations. Since it is a status check, it is likely safe, but transparency is lacking.

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, concise sentence that efficiently communicates the tool's purpose and key behaviors. It avoids unnecessary detail and is well-structured, making it easy for an agent to parse quickly.

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?

Given the simplicity of the tool (one string parameter, no output schema, no annotations), the description provides sufficient context to understand its function and expected input. It covers the main behaviors (status and reply) without needing extensive detail, though it omits output format specifics.

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 parameter message_id is described indirectly as the ID of the message you sent, providing basic context. However, the schema has no description for this parameter, and the tool description does not clarify whether it expects a specific format, length, or any additional constraints. The semantics are inferable but not fully explicit.

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 checks the status of a sent message, listing possible states (queued/delivered/replied/expired) and mentioning that the reply is included once available. It distinguishes from sibling tools like bus_send and bus_reply by focusing on status retrieval, though it could be more explicit about the action (e.g., 'retrieve status').

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 usage for checking the status of a message after sending, which is inferable from the context and sibling tool names. However, it does not explicitly state when to use this tool versus alternatives or provide any usage conditions, leaving some ambiguity for an agent.

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