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

With no annotations, the description carries the full burden and does well: it declares the return shape {allowed, level, upgrade_to}, states the tool is free (no cost/rate concern), and characterizes the operation as a deterministic check. It does not state error behavior for unrecognized 'use' values or whether the check is logged/audited, which keeps 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?

Three short sentences: what it decides, what it returns, and why it exists. Nothing is redundant and the key purpose is 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?

For a two-parameter predicate with no output schema and no annotations, the description supplies the decision semantics, the return contract, and the cost profile – enough to call it correctly. The remaining hole is the undocumented 'cvin' input and behavior on unknown use values.

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 50% – 'use' is well documented in the schema with the same examples the description repeats, while 'cvin' has no schema description at all. The description only indirectly compensates by framing cvin as an '身份级别', so the format/encoding of that identifier remains unexplained.

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?

It names a specific verb (judge/check) and resource (whether an identity level permits a given use), with concrete use examples ('抵押登记'/'保险核保'/'资产池入池') that make the intent unmistakable. It does not explicitly distinguish itself from near neighbors such as cvin_identity or cvin_verify, so sibling differentiation is only implicit.

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?

Usage is implied: call it as a gate before an action that requires a level ('由机器把关'), and the returned upgrade_to hints at a remediation path. There is no explicit when-not guidance and no named alternative for related lookups (e.g. fetching a raw level via cvin_identity), so the agent must infer routing.

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