credit_depositPay USDC once and receive spendable Aura credit. Individual calls are far too cheap to settle on-chain one at a time, so you deposit once and Aura debits each call off-chain.
When to use: Call when your balance is low, or when a paid call returns 402. A US$1 deposit covers hundreds of operations.
Price: Free.
| Name | Required | Description | Default |
|---|---|---|---|
| amount_usd | No | How much credit to buy. | 1 |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds meaningful behavioral context beyond the annotations: it explains that Aura debits each call off-chain after a one-time deposit, and that the tool is free. It does not contradict the readOnlyHint=false or openWorldHint=false flags, and it provides enough behavioral detail for a payment/deposit tool.
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 well-structured with clear sections: core behavior, when to use, and price. It is slightly repetitive between 'Pay USDC once' and 'you deposit once,' but every section earns its place and the most important guidance is front-loaded.
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 is adequately complete: it covers purpose, trigger conditions, mechanics, and cost implications. Some details like refunds or deposit confirmation are absent, but they are not essential for selecting and invoking this tool correctly.
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 already fully documents the single parameter with an enum, default, and description, so the baseline is 3. The description adds practical context with 'A US$1 deposit covers hundreds of operations,' but does not describe the amount_usd parameter itself beyond that.
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 a specific verb and resource: 'Pay USDC once and receive spendable Aura credit.' It clearly distinguishes the deposit action from related operations like memory or inbox tools, and the title 'Top up balance' reinforces the purpose without ambiguity.
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 states when to call the tool: 'Call when your balance is low, or when a paid call returns 402.' It also provides rationale for the deposit model, explaining that individual calls are 'far too cheap to settle on-chain one at a time,' which guides the agent away from overusing it.
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 addresses a distinct resource or action: memory operations are clearly separated from inbox operations, await/park/resume are differentiated by whether the process stays alive or hands off state, and administrative calls like capabilities, whoami, and credit_deposit have non-overlapping purposes. No two tools appear interchangeable.
Most resource operations follow an object_verb pattern (memory_get, hook_create, inbox_list), but core primitives like await, park, resume, and signal are bare verbs, while capabilities and whoami are bare nouns. The style is consistently lowercase snake_case and readable, but the naming convention is mixed rather than uniform.
At 16 tools the set is just past the typical well-scoped range, but each tool maps to a distinct platform capability: identity, inbox, memory, hooks/signals, parking, and billing. It feels slightly heavy rather than bloated.
The core agent workflow is covered end to end: identity creation, credit deposit, hook creation, awaiting triggers, inbox reading, durable memory, and the park/resume round-trip. Minor gaps remain—there is no hook list/delete and no way to cancel a parked state—but they can be worked around rather than blocking.