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

With no annotations provided, the description carries the full burden and delivers rich behavioral context. It reveals the 0.05 USDC cost, the JSON-RPC error for unpaid calls, the auto-construction of EIP-3009 signatures by wallet-capable clients, and explicit limitations (no payment, no settlement, no fund movement). This goes beyond a simple 'checks terms' statement.

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 moderately long but densely informative, front-loading the purpose and then methodically covering behavior, cost, errors, and limitations. Every sentence contributes value, though it could be slightly tightened by removing redundant phrasing such as 'LION does NOT perform payment inside MCP' and 'no fund movement' which overlap.

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?

Despite having an output schema, the description lists all major return fields (blockers, policy fit, recipe, funnel stage, readiness score, risk flags), explains the error condition, states the cost, and clarifies the tool's scope limitations. For a tool with one parameter and no annotations, this is a comprehensively complete description.

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 sole parameter `url` is fully described in the schema (pattern, format, description). The description only mentions it as a 'target x402/MCP service URL' without adding new semantic details beyond the schema. With 100% schema coverage, the baseline of 3 is appropriate.

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 opens with a specific verb+resource: "Pre-spend payment-term trust check for x402 endpoints." It clearly states the tool audits payment terms before signing a Payment-Signature, distinguishing it from sibling data-query tools. The purpose is further clarified by enumerating the exact outputs (blockers, policy fit, recipe, funnel stage, readiness score, risk flags).

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?

Explicit when-to-use guidance is provided: "Before your agent signs a Payment-Signature, call this." It also gives when-not-to-use caveats: LION does not perform payment, is not a smart-contract security audit, and provides no settlement guarantee. While no alternative tool is named, the exclusions and context are clear.

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