get_vault_balance

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the behavioral disclosure burden. 'Checks' implies a non-mutating read, and naming balance and session status gives useful context. Still, it does not mention auth requirements, side effects, or what happens with invalid or expired addresses, so some transparency gaps remain.

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, concise sentence with the action verb front-loaded and no unnecessary detail. Every word contributes meaning and the structure is immediately scannable.

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?

Given the tool has only one parameter, no annotations, and an output schema present, the description covers the essential context. It could additionally state when to prefer this tool or clarify session status behavior, but for a simple balance/status check the description is nearly 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?

The schema has 0% description coverage for the single required parameter, so the description must compensate. It clarifies that 'agent_address_or_key' can be either an agent wallet address or a session key, adding meaning beyond the parameter name. It does not provide format examples, but for one straightforward parameter this is sufficient.

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 a specific verb ('Checks'), a specific resource ('remaining pre-funded USDC balance and session status'), and a target ('agent wallet address or session key'). It distinguishes the tool from sibling 'get_payment_info' by focusing on vault balance and session status rather than payment information.

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 intended use is implied: it is for checking an agent's vault balance and session status. However, there is no explicit guidance about when to use this tool versus siblings, prerequisites, or conditions that would make it the right choice. For a simple read operation, this is adequate but not fully explicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.