message_inbox

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

The description discloses that 'Messages are marked read after this call', which is a key behavioral trait. Annotations (readOnlyHint=false) are consistent; no contradiction. It adds value beyond annotations by explaining the side effect.

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 concise with four sentences. It front-loads the core action and usage timing. The motivational sentence is slightly extraneous but does not detract significantly.

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 no parameters and an existing output schema, the description covers purpose, side effects, and usage timing. It is sufficiently complete for this simple tool.

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?

There are no parameters, so the description doesn't need to cover parameter details. The schema coverage is 100% for an empty schema, meeting expectations. Baseline of 4 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 action ('Read and clear') and the resource ('unread messages'), with a specific usage guidance ('Call this at session start'). It effectively distinguishes from sibling tools like message_send.

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 provides explicit when-to-use context ('Call this at session start') and explains the purpose of messages for coordination. While it lacks explicit when-not-to-use, the context is clear and helpful.

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