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 the authentication prerequisite and the fact that start_login does not open this tool, which is useful behavioral context. However, it doesn't disclose what happens if unauthenticated, whether it returns an empty list vs error, or any rate limits. The description adds some value but not rich behavioral detail.

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 two short sentences with zero waste. The core purpose is front-loaded, and the access note is separated clearly. Every sentence earns its place.

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 list tool with one parameter and no output schema, the description is nearly complete. It covers the purpose, the required parameter, and the authentication prerequisite. It could mention what the response contains (e.g., challenger details), but the tool's simplicity and the 100% schema coverage make the missing return-format detail minor.

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%: the only parameter, hitl_id, is described as 'HITL config ID' with a regex pattern. The description adds no additional meaning beyond the schema, so baseline 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 states a specific verb ('List') and resource ('Proof-Me challengers enrolled on a HITL config'), which clearly identifies what the tool does. It doesn't explicitly distinguish from sibling tools like invite_challenger or remove_challenger, but the resource and scope are clear enough.

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 clear access context: requires a Proof account, authentication via /mcp → Authenticate, and explicitly notes that start_login does NOT open this tool. It doesn't explicitly name alternatives or when-not-to-use, but the access guidance is actionable and specific.

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