Check an agent's pre-funded USDC vault balance, total consumed, query count, and remaining query capacity across tiers.
Retrieves pre-funded USDC vault balance, total consumed, query count, and remaining query capacity across tiers for an agent.
| Name | Required | Description | Default |
|---|---|---|---|
| session_key | No | Agent session key (vault_key_...) | |
| agent_address | No | Agent Polygon address (0x...) |
Changes observed during successful MCP inspections.
v1.0.6Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It does disclose the shape of the returned data (balance, consumed, query count, tier capacity), which is useful since there is no output schema, but it omits the read-only nature, permission/auth requirements, and whether the call is billable or consumes quota.
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?
A single front-loaded sentence that packs in the resource and the enumerated return fields with no wasted words or 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 read tool with no annotations and no output schema, listing the return fields partially compensates. However, it leaves gaps on when to use it, the required-vs-optional nature of the two identifiers, and any permission constraints — enough to make it only minimally complete.
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%, so both parameters (session_key, agent_address) are already documented in the schema. The description adds nothing about their semantics — notably it never clarifies whether either is required or how the two identify the same agent. Baseline 3 applies when the schema does the heavy lifting.
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?
States a specific verb ('Retrieves') and resource ('pre-funded USDC vault balance') and enumerates the returned data points (consumed, query count, remaining capacity across tiers). It is distinguishable from every sibling, none of which touch agent vault balances, though it doesn't explicitly name a sibling it is not.
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?
No guidance on when to call this versus alternatives, and no prerequisites stated. The description never explains that a session or registered agent must exist first, nor how it relates to open_agent_session/get_agent_session_info. The agent must infer context entirely.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.