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

No annotations, so the description carries the burden. It discloses the notable behaviors: full-depth calls are paid (0.005 USDC via x402_payment) and 'prints' are settled-only, implying no unsettled prints are returned. It omits whether payment is required up front, what happens if x402_payment is missing for depth=full, or any rate/auth constraints.

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?

Two dense sentences with no filler; both carry information. However, the most important element — what the tool actually returns — is buried behind domain jargon rather than front-loaded.

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 annotations and no output schema, the description should cover more. It gives the field vocabulary and the cost model but not the response shape, symbol format, or the payment failure path — gaps an agent would hit on first call.

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 0%, so the description must compensate. It meaningfully explains the depth enum values ('top' is free, 'full' costs 0.005 USDC) and the role of x402_payment, which is the non-obvious parameter — but 'symbol' is never explained (format, case, valid instrument identifiers) and payment mechanics remain undefined.

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 never states the verb or resource directly — it opens with a glossary of return fields ('Bids = open demands, asks = standing offers, prints = settled prices'). An agent can infer this returns order-book data, but nothing distinguishes it from siblings like quote_instrument, get_market, or get_feed.

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?

'Top of book free; full depth 0.005 USDC' gives real guidance for choosing between the two depth values based on cost. However, there is no guidance on when to use this tool versus quote_instrument or get_market, nor any stated prerequisite for the payment flow.

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