Ban MQTT Client

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

Annotations already include destructiveHint=true, and the description reinforces it with '[DESTRUCTIVE]'. It adds context beyond annotations: persistence, expiration, and how to lift the ban. However, it does not clarify whether existing connections are terminated, which is a minor transparency gap.

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 destructive warning and core action. Every sentence adds value: the persistence note and the contrast with emqx_kick_client are both necessary for correct tool selection.

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 mutation tool with full annotation coverage and an output schema, the description covers the essential behavior: blocking, persistence, and reversal. It does not explicitly mention the effect on existing connections, but the provided information is largely sufficient for an agent to invoke the tool 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?

The input schema provides 100% parameter coverage with detailed descriptions (e.g., who, until, reason, subject_type). The description adds no additional parameter-specific meaning beyond what the schema already states, so the baseline score of 3 is appropriate.

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 action: 'Block a client id, username or IP from connecting,' which is specific and resource-oriented. It also distinguishes from the sibling tool emqx_kick_client by explaining the persistence, making the purpose unmistakable.

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?

Explicitly contrasts with emqx_kick_client: 'Unlike emqx_kick_client this persists' and references emqx_unban as the way to lift the ban. This gives the agent clear guidance on when to use this tool versus alternatives.

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