set_message_read

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

No annotations are provided, so the description carries the burden. It discloses that the tool works by viewing the message, which is a mechanism detail. Critically, it states that unread is not supported — a significant behavioral limitation. It doesn't mention potential side effects (e.g., idempotency, permissions), but for a simple mutation this is adequate.

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 extremely concise: two sentences plus a note. Every sentence has purpose — the first states the action, the second explains the mechanism, and the note addresses a key limitation. The structure front-loads the purpose immediately.

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 tool with a single parameter, an output schema, and a clear description, this is complete. It covers the action, the mechanism, and the unread limitation. No additional context is needed for an AI agent to select and invoke this 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?

Schema description coverage is 100%, so the baseline is 3. The description adds no extra parameter details beyond what the schema already provides (message_id). It doesn't explain IDs, formats, or how they relate to the viewing action, but that's unnecessary given the schema.

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?

Description uses a specific verb+resource construction: "Mark a message as read." It clearly distinguishes itself from sibling tools like get_message and get_messages by emphasizing that it explicitly triggers the read state rather than simply retrieving content. The distinction is meaningful because Wilma auto-marks messages as read when viewed.

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 clarifies when to use the tool: to explicitly trigger a read state without needing to read the message content. It also notes that Wilma does not support unread, which is an exclusion. However, it doesn't explicitly name alternatives (e.g., get_message) or explain why you'd choose this over them, so guidance is implied rather than fully explicit.

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