credit_depositBuy Vortex credit with USDC on Base over x402. One on-chain settlement, then every call is debited off-chain.
When to use: Call when your balance is low. Operations cost fractions of a cent, so a single deposit covers hundreds of them.
Price: Free.
| Name | Required | Description | Default |
|---|---|---|---|
| amount_usd | No | One of 1, 5 or 20. Defaults to 1. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description goes beyond the readOnlyHint=false annotation by explaining the settlement model: 'One on-chain settlement, then every call is debited off-chain.' It also clarifies that the tool is free despite being a purchase. It stops short of mentioning potential requirements or outcomes like wallet approval or the returned transaction status.
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 compact and front-loaded: action, usage trigger, and price are each given in a distinct sentence or short section. Every sentence earns its place, and there is no repetition of schema or title information.
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 one-parameter top-up tool, the description covers the purpose, when to use it, the on-chain settlement model, and the cost implications. It does not describe the response format (e.g., confirmation or new balance), but given the simple, low-complexity action and lack of an output schema, this is a minor gap.
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 fully documents amount_usd with description 'One of 1, 5 or 20. Defaults to 1.', and coverage is 100%. The description adds no parameter-level detail, but with this high schema coverage the baseline 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 opens with 'Buy Vortex credit with USDC on Base over x402' — a specific verb, resource, and payment rail. The title 'Top up balance' is consistent, and no sibling tool appears to be a credit/payment tool, so there is no ambiguity about what this tool does.
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 explicitly says 'When to use: Call when your balance is low.' It also adds economic context by noting that operations cost fractions of a cent, so a single deposit covers many calls. This gives the agent a clear condition for selecting this tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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Each tool has a clearly distinct role: search (find), reach verification (feasibility), cost breakdown (landed), price history (history), alerts (watch), and account management (identity_create, credit_deposit, whoami). Even the overlapping cross-border tools are differentiated by their focus and explicit when-to-use guidance.
Names are all lowercase and readable, but they follow no strong pattern: some are bare verbs (find, report, watch), some are nouns (capabilities, history, feasibility), and two use underscores with different structures (credit_deposit, identity_create). It is not chaotic, but the convention is mixed.
Ten tools is a well-scoped set for a cross-border commerce intelligence service. Each tool covers a distinct operation, from discovery and feasibility to landed cost, monitoring, and account management, without unnecessary redundancy.
The core workflow is well covered: find products, check reach, estimate landed cost, review history, watch for changes, and report outcomes. Minor gaps exist, such as no way to list or cancel watches, but the essential lifecycle for the service's purpose is present.