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

The annotations only provide generic non-read-only and non-idempotent flags. The description adds materially useful behavioral detail: it is an internal transfer, the trading key alone is allowed to make it, the $0.95 gas reserve is preserved, and the default behavior matches the web app. This is exactly the kind of context an agent needs before calling.

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 appropriately sized and well structured: a clear first sentence naming the operation, two sentences explaining the amount semantics, and a final sentence giving the invocation condition. Every sentence earns its place with no filler or restated annotations.

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-optional-parameter tool with no output schema, the description is complete enough: it covers purpose, amount behavior, gas-reserve constraint, auth context, and when to use it. An agent can confidently select and invoke the tool without consulting additional context.

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 documents amountUsd at 100% coverage, so the baseline is a 3. The description adds value by explaining the optional behavior precisely: omitting the parameter moves everything above the $0.95 reserve, while providing a value moves exactly that much only if the reserve remains intact. This justifies slightly above baseline.

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 states a specific verb and resource: deposit USDC from the wallet into the trading subaccount so it becomes collateral. It also explicitly clarifies that funds never leave the account, immediately distinguishing this from external transfer or withdrawal tools.

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 gives an explicit use case: use it when the user has sent money and the subaccount collateral is 0 or too low to trade. It also explains the two modes (with and without amountUsd). It does not explicitly name a sibling alternative or a when-not-to-use condition, so it stops just short of a 5.

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