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

Annotations only supply safety hints; the description adds substantial behavior: it returns UNSIGNED tx bytes simulated against mainnet, validates tick/lot/min size, charges fees in the input coin (no DEEP), and is non-custodial. These disclosures go well beyond what readOnlyHint/destructiveHint provide, and they reinforce rather than contradict the read-only annotation.

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 core action is front-loaded, but the text is padded with redundancy: 'No leverage' and 'Spot only, no leverage' repeat, and 'Returns UNSIGNED tx bytes' is restated as 'returns quotes and UNSIGNED transactions only.' The 'Education only, not financial advice' disclaimer is boilerplate rather than tool guidance.

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?

No output schema exists, so the description correctly states the return (unsigned tx bytes). For a 10-parameter tx-building tool it covers the essential behavioral facts (constraints, fees, custody model), though it omits per-parameter detail on several fields.

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 coverage is 60% (10 params, several undocumented). The description clarifies deposit_first ('funds it in the same tx') and the fee-coin semantics, but pool/side/price/quantity/post_only/expire_hours/client_order_id are left entirely to the schema. It adds partial value but does not compensate for the coverage gap.

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 and resource ('Place a spot limit order on a DeepBook v3 pool from your BalanceManager') with clear scope (spot only, v3). An agent can distinguish it from build_swap_tx, build_cancel_order_tx, and the deposit/withdraw siblings without opening any schema.

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 scope constraints (spot only, no leverage, from BalanceManager) and mentions the deposit_first option, which implies when it applies. However, it never names an alternative tool or an explicit when-not condition, so routing versus build_swap_tx is left to inference.

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