Purchase APIHub credits via x402 (USDC on Base). Returns payment instructions including a web URL for browser-based payment, a CLI command, and raw x402 requirements for agents with wallet support. Credits are added to your account instantly once payment confirms on-chain.
| Name | Required | Description | Default |
|---|---|---|---|
| amount_dollars | Yes | Amount to top up in USD. Minimum $5.00, maximum $10,000 per call. Example: 10 for $10. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden. It discloses that the tool returns payment instructions in three formats (web URL, CLI command, raw x402 requirements) and that credits are added after on-chain payment confirmation. This is strong transparency, though it does not cover error handling or prerequisites like wallet configuration.
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 concise and front-loaded, with the main purpose first, followed by return details and confirmation behavior. Each sentence earns its place with no redundancy.
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 one-parameter tool with no output schema, the description covers the purpose, return format, and post-payment behavior. It is adequately complete, though it does not elaborate on edge cases or prerequisites beyond what is in the schema.
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 schema already details the parameter with minimums, maximums, and an example. The description itself adds no extra semantics beyond the schema, so the baseline score of 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 clearly states the tool's purpose: 'Purchase APIHub credits via x402'. It uses a specific verb ('Purchase') and identifies the resource ('APIHub credits'), and also specifies the payment method (USDC on Base). It distinguishes itself from sibling tools by describing unique output (payment instructions).
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 usage for topping up credits but does not explicitly mention when to use this tool versus alternatives like checking balance or making calls. There is no mention of alternative tools or exclusions, so the guidance is only implied by the purpose.
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.
Each tool has a clearly distinct role: balance check, service discovery (list/search), service details, paid calls (onboarded vs external vs content), and credit top-up. The similar pairs (search vs search_external, call vs call_external) are separated by onboarded vs external scope, and descriptions explicitly guide selection.
All names share the 'apihub_' prefix and use snake_case, with verbs like get, list, search, call, read. However, 'balance' and 'topup' deviate from the verb_noun pattern, making the convention slightly inconsistent but still predictable and readable.
With 9 tools, the set is well-scoped for a credit-based API marketplace. Each tool serves a distinct step in the workflow (discover, inspect, call, manage funds), with no redundant tools and nothing missing at the broad level.
The surface covers the full lifecycle: searching and listing services, retrieving details, making calls to both onboarded and external APIs, reading content, checking balance, and topping up credits. Minor gaps like transaction history or service ratings exist but do not hinder the core purpose.