Return the x402 payment challenge for purchasing a public product. This wraps the existing public /p/:id-or-slug flow and does not require owner credentials.
| Name | Required | Description | Default |
|---|---|---|---|
| metadata | No | Optional metadata object forwarded to the purchase flow | |
| productIdOrSlug | Yes | Product slug or product ID used in the public /p/:id-or-slug purchase route | |
| clientReferenceId | No | Optional client reference ID forwarded to the purchase flow |
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 does disclose key traits: it returns a challenge (not a completed purchase), wraps a public route, and requires no owner credentials. Yet it does not mention what the challenge contains, whether there are side effects, idempotency, or rate limits. This is adequate but not rich.
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 sentences, concise, and front-loaded. The first sentence states the core action and resource, while the second provides context and a key differentiator. Every word earns its place with no 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 3 parameters (one required) and no output schema. The description explains the purpose and the wrapped route but doesn't describe the shape or structure of the returned challenge. Since this is part of a payment flow, the absence of output details and the relationship to purchase_product_with_payment leave some gaps for an agent deciding how to use the result.
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 input schema has 100% parameter coverage, with clear descriptions for productIdOrSlug, metadata, and clientReferenceId. The description adds context by referencing the 'public /p/:id-or-slug' route, reinforcing the meaning of productIdOrSlug. It does not need to add more because the schema already documents each parameter.
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: 'Return the x402 payment challenge for purchasing a public product.' It identifies a specific verb (return), a resource (payment challenge), and the context (public product). It also distinguishes itself from sibling tools like purchase_product_with_payment by emphasizing it returns a challenge rather than executing a purchase.
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 usage context: it wraps the public /p/:id-or-slug flow and notes that it 'does not require owner credentials.' This implies use for public products and when the caller lacks owner credentials. However, it does not explicitly name alternative tools or state when to prefer other payment request tools, so it falls short of full exclusion guidance.
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.
Most tools pair a clear verb with a distinct resource noun, so endpoints, agents, datasets, campaigns, products, and vault operations are generally easy to separate. The main risk is the repeated request_*_payment / *_with_payment pairs and the two create_*_with_payment tools, which are only distinguishable by reading descriptions carefully.
The dominant pattern is verb_noun snake_case, such as list_my_endpoints, update_campaign, and finalize_agent_registration, and the payment/request pairs are consistently named. The vault_* tools use a namespace prefix rather than verb-first names, and vault_how_to_backup breaks the action-oriented convention, so it is not perfectly uniform.
48 tools is a very large MCP surface, well beyond the 25-tool threshold where selection becomes a serious burden. Even though the server spans multiple domains, the count feels excessive for a single agent-facing tool set and should likely be split by domain.
The core endpoint, agent, marketplace, and payment flows are well covered, including creation, updates, stats, and two-phase x402 purchases. However, there is no create_product or delete_product, campaigns lack delete, and there is no way to list previously purchased datasets, leaving notable lifecycle gaps.