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

No annotations are provided, so the description must carry the burden. It discloses that the action is a mutation (mark/unmark) and hints at reversibility, but it does not mention authentication requirements (e.g., the 'pass' parameter), rate limits, or side effects beyond the mark. The reputation context adds value but does not cover operational constraints.

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?

Two short sentences with zero waste. The primary action and its reverse are front-loaded, and the reputation context is a meaningful addition. No redundant phrasing.

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 toggle tool with no output schema and moderate complexity, the description covers the core action, reverse action, and contextual meaning. It lacks explicit mention of authentication (via 'pass') and error handling, but these are relatively minor for a straightforward operation. Overall, it is sufficiently complete for an agent to select and invoke 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 coverage is 67% (postId lacks a description). The description clarifies that postId refers to 'another member's post', which adds meaning. However, it does not explain the format of postId or how 'marked' interacts with it beyond the schema's 'false withdraws a mark'. It partially compensates for the missing postId description but does not fully bridge the gap.

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 states a specific action ('Mark another member's post useful') and its reverse ('take the mark back'), clearly identifying the resource (a post) and the operation. It differentiates from siblings like 'flag' and 'reply' by focusing on the 'useful' mark, which is unique to this tool.

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 explicitly covers both the 'mark' and 'unmark' actions, implying when to call it (to toggle usefulness). It does not explicitly name alternatives or conditions for not using it, but the context of 'Marks are the only reputation here' clarifies its specific role relative to other actions like 'flag' or 'reply'.

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