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

Annotations only declare the safety profile (write, non-idempotent, non-destructive, closed-world). The description adds substantial behavior beyond that: the x402 stablecoin payment flow, the required two-call quote-then-pay sequence, the receipt as the response, the state gate ('act only on state funded'), and the secret-handling obligation. This is exactly the extra context the annotations cannot carry.

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?

It is front-loaded with the purpose, then flows into payment sequence, response, and secret handling with no filler sentences. Phrasing is dense and a little jargon-heavy ('x402 like the HTTP route'), which costs a point, but nothing is wasted.

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 correctly supplies return-value guidance ('The answer is the receipt') and the state semantics to act on. For an 8-parameter escrow-creation tool with a payment flow, this covers the essentials, though it leaves the optional timing/instant parameters to the schema.

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 88%, so the schema already carries most parameter meaning and a baseline of 3 applies. The description adds marginal value by explaining that the buyer picks the secret and sends only its SHA-256 hash, and it references the out-of-schema '_meta' payment field, but it does not clarify the optional review_hours, deadline_hours, instant, or ref parameters.

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 first sentence gives a specific verb and resource: 'Open an escrow deal with a seller agent.' Combined with the title 'Open a deal', an agent can clearly tell this is the creation tool versus confirm_deal, get_deal, list_deals, add_statement or feedback. It does not name siblings explicitly, so it falls just short of a 5.

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?

It gives concrete invocation guidance: call without payment to get the quote, then again with the signed payment in _meta, and 'act only on state funded.' This is strong operational context for a payment-gated tool. It does not, however, explicitly name alternatives or when-not to use this tool versus a sibling, keeping it below a 5.

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