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

Goes well beyond the annotations (readOnly=false, idempotent=false, openWorld=true) by disclosing cost ('free'), account restriction, the exact return shape (operation_id + signatures_needed[]), per-signer signing recipes ('owner' P-256 over payload_b64 with verify-line checking, 'trading_key' EIP-712 typed_data), and a hard 5-minute submission deadline. This is exactly the multi-step, security-sensitive behavior an agent cannot infer from structured fields.

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?

Front-loads the action and scope in the first clause, then the return/signing workflow. The dense dash-chained sentence is information-rich but slightly hard to parse, costing it a perfect score.

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?

With no output schema, the description takes on the burden of describing returns (operation_id, signatures_needed[]) and the mandatory next call (submit_operation) with its deadline. For a two-parameter, non-idempotent preparation tool, nothing an agent needs to invoke it correctly is missing.

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% and both parameters are documented in-schema, so baseline 3 applies. The description reinforces directionality ('between spot and perps') but adds no new detail about amount_usd units, precision, or limits beyond what the schema already says.

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 concrete verb+resource+scope: 'Move USDC between spot and perps inside your trading wallet', plus qualifying constraints ('classic accounts only; free'). This clearly separates it from siblings like move_funds, send_trading_funds_home, or earn_usdc_deposit without the agent needing to open schemas.

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?

Gives a clear operating context and a full follow-up path: sign each step, then call submit_operation within 5 minutes. It also implies eligibility ('classic accounts only'). It does not explicitly name alternative sibling tools (e.g. move_funds) or state when *not* to use this, so it falls 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.