mark_channel_viewed

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

Discloses behavioral effects: 'Clears unread counters and advances last_viewed_at'. Warns about clearing UI badges for shared accounts. No annotations contradicted; destructiveHint=false is consistent.

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 paragraph with dense but clear sentences. It is well-structured and front-loaded with the primary purpose, but slightly longer than necessary due to detailed usage examples.

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 simple tool with one parameter and no output schema, the description covers purpose, usage guidance, behavioral effects, and an anti-pattern. It is fully sufficient for correct agent invocation.

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 coverage is 100% with a clear description of the channel_id format. The tool description adds no additional parameter semantics beyond what the schema already provides, so 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 action 'Mark a channel as read' and the resource 'channel for authenticated user'. It distinguishes this tool from siblings like leave_channel or create_channel by focusing on read state management.

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 provides three specific use cases (user asks to clear unreads, bot processing unread messages, bootstrap with last_viewed_at==0) and an explicit anti-pattern ('Do NOT call on accounts shared with humans').

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