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

Annotations already cover safety (readOnly, idempotent, non-destructive, open-world), and the description adds genuinely non-obvious operational context: this is a paid call at $0.09 USDC per invocation, payment must travel in MCP headers (X-Payment / X-Payment-Tx / Bearer fg_…) and explicitly not in parameters. That payment/auth detail is exactly the kind of behavior an agent would otherwise get wrong. It does not mention rate limits or latency, keeping it from a 5.

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 purpose is front-loaded and the payment warning is well placed, but the content is triplicated: a Chinese/English purpose block, then a zh paragraph, then an en paragraph restating the same args and price. Roughly half the text is duplication across languages, which adds length without adding information.

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 compensates by enumerating the returned fields (implementation address, proxy mode, owner/renouncement, pause state, risk explanations with boundaries), and it fully covers the payment prerequisite. The only real gap is chain-parameter semantics, which is left entirely to an undocumented 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 0% for two parameters, so the description must carry the meaning — but it only restates the names ('入参：address、chain'). It never explains the accepted chain format, whether chain is optional, or what happens when chain is omitted (the schema merely shows a null default), which leaves the one optional parameter ambiguous.

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 states a specific verb+resource ('full verification' of a contract) and enumerates concrete outputs: implementation address, proxy mode, owner and renouncement status, pause state, and per-signal risk explanations with decision boundaries. That is far beyond the tool name alone. It stops short of 5 because it never contrasts itself with the sibling 'contract-fingerprint.peek', so the agent cannot tell from the text which of the two to pick.

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 framing 'Ask "what does this contract actually do" — full: ...' implies this is the comprehensive variant used when a deep check is wanted, and the word 'full' hints at a lighter alternative. However, no alternative is named and no when-not-to-use condition (e.g., cost-sensitive quick lookups) is given, so guidance remains implied rather than explicit.

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