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 indicates the tool returns payment instructions, with no mention of side effects, authentication needs, rate limits, or return format. This is minimal and leaves significant gaps for an agent.

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, compact sentence that uses 'PAID (x402)' as a contextual prefix and immediately states the action and scope. Every word contributes meaning, with no redundant phrasing or fluff.

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?

The tool has no output schema and no annotations, so the description must explain the return value and behavior fully. It only says 'returns x402 payment instructions,' leaving the structure, pagination, and exact contents of the snapshot undefined. This is insufficient for an agent to predict the tool's output.

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 tool has zero parameters, so the input schema is fully complete. Per the rubric, the baseline for zero parameters is 4, and the description adds context by specifying the full liveness-probed feed, which helps clarify the scope of the data returned.

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 tool returns x402 payment instructions for the full liveness-probed services feed, using a specific verb and resource. It distinguishes itself from sibling tool list_x402_services by emphasizing payment instructions and the full feed scope.

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?

No explicit guidance on when to use this tool versus alternatives like list_x402_services or get_mcp_registry_snapshot. The 'PAID (x402)' prefix hints at a paid-service context, but it does not state when to choose this over other tools or any exclusions.

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