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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states an authentication requirement, but does not mention side effects, idempotency, reversibility, or return behavior. For a mutation action, this is insufficient.

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, efficient sentence that immediately states the core action and the key constraint. All words earn their place, with no redundancy. Front-loaded purpose makes it easy to scan.

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 three parameters and no output schema, the description is minimal. It does not explain how to obtain the message ID or when to use room_name versus talent_slug, though the schema references the source tools. The description is adequate but leaves the param interplay to the schema, which is acceptable but not rich.

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 schema has 100% description coverage for all three parameters, so the baseline is 3. The description's mention of 'by its ID' aligns with message_id but adds no extra meaning beyond the schema. It does not clarify the relationship or usage trade-offs between room_name and talent_slug.

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 verb 'mark' and the resource 'a message as read,' with the required identifier. It does not explicitly differentiate from sibling tools like send_message or get_conversation, but the purpose is unambiguous. Lacks explicit sibling differentiation, so not a 5.

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 no guidance on when to use this tool versus alternatives such as send_message or start_conversation. It mentions a prerequisite (employer authentication) but no context for selection. No usage scenarios or exclusions are given.

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