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

The annotations already mark the tool as read-only and closed-world, and the description adds important context: it returns a paid URL and wallet steps, and no funds move until the wallet or user authorizes the x402 request. That clarifies the safety gate beyond the annotations, though it does not describe edge cases or error behavior.

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 compact sentences with the core output and the payment-authorization constraint front-loaded. There is no wasted text.

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 zero-parameter preparation tool with no output schema, the description adequately explains what is returned (paid URL and wallet steps) and the crucial safety condition (no funds move without authorization). It could be slightly more complete if it clarified how this differs from the generic purchase-preparation sibling.

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 input parameters, so there is nothing for the description to disambiguate. The baseline for zero-parameter tools applies.

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 gives a specific verb and resource: returning the exact paid URL and wallet steps for the TZ SELECT 4H setup. It clearly identifies the asset-specific scope, though it does not explicitly say how it differs from the generic prepare_4h_setup_purchase sibling.

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 implies this is the preparation step for a TZ SELECT 4H purchase and notes that funds only move after authorization. However, it gives no explicit guidance on when to use this tool versus discover_4h_setups or prepare_4h_setup_purchase.

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