check_paywallCheck whether an address has paid for a specific x402 paywall. Returns pricing info if not paid, or content access status if paid.
| Name | Required | Description | Default |
|---|---|---|---|
| address | No | Wallet address to check (optional) | |
| paywallId | Yes | Paywall ID |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, which cover safety and side-effect expectations. The description adds valuable context by explaining the conditional return behavior: pricing info if not paid, content access status if paid. This goes beyond what annotations provide and gives a clear picture of what the tool will do.
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 sentence that front-loads the main purpose and includes the key outcome detail. It is concise, clear, and free of unnecessary words. Every word contributes to understanding the tool's behavior.
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?
Given the tool's low complexity (two parameters, no nested objects, no output schema), the description is largely complete. It explains the return scenarios and the core function. However, it does not explicitly mention that the address is optional or describe possible errors/edge cases, so it is not fully comprehensive, but it is adequate for a simple read-only tool.
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 describes both parameters (address and paywallId) with 100% coverage. The description does not add much detail beyond the schema; it mentions the address and specific paywall but does not explain formats or any parameter interactions. Since schema coverage is high, the baseline is 3, and the description neither improves nor degrades it.
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's function: checking if an address has paid for an x402 paywall. It specifies the resource (paywall access) and the action (check), and it differentiates the outcome between pricing info and content access status. However, it does not explicitly distinguish itself from sibling tools like verify_receipt or get_checkout_status, so it loses one point for lacking that differentiation.
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 the tool is used to check paywall payment status, which gives some context. However, it does not explicitly state when to use this tool over alternatives, nor does it mention any prerequisites or exclusions. The usage context is clear enough to infer, but there is no direct guidance on selection among sibling tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Several tools overlap in the product discovery and payment status domains. discover_merchants, search_products, and get_merchant_profile all relate to finding products/merchants, though descriptions clarify intended use. Similarly, check_paywall, get_checkout_status, and verify_receipt all deal with payment status/verification, creating potential agent confusion.
Most tools follow a consistent lowercase verb_noun pattern (check_paywall, create_checkout, download_product, get_0g_health, etc.). The one outlier is agent_wallet_status, which is a noun phrase instead of verb-first, but it still uses underscores and fits thematically.
13 tools is within the ideal range and the server covers payments, product discovery, and verification. A few tools like get_0g_health and setup_instructions feel tangential to the core payment flow, making the set slightly heavier than necessary but still reasonable.
The payment lifecycle is well covered: discover/search products, pay via checkout or direct merchant payment, download digital goods, and verify receipts. Minor gaps exist such as no explicit refund or transaction history tool, but agents can work around these by using existing verification and wallet status tools.