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

No annotations exist, so the description carries the full burden. It does disclose one genuinely useful behavioral trait — below 200 events only counts are returned, no ratios — plus that the tool is free. However, it says nothing about read-only nature, latency, caching, or the shape of what comes back, which leaves meaningful gaps for a no-annotation tool.

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?

Very compact and front-loaded: the metric list comes first, then the threshold rule, then the cost note. The parenthetical '（先计数后比率）' restates the preceding clause and is mild redundancy, keeping it from a 5.

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?

There is no output schema and no annotations, so the description must convey what comes back — it does so by enumerating the output categories (distributions and counts) and defining the threshold gating rule. An agent can call it correctly with no inputs. What is missing is any hint of the response structure or scoping (e.g. global vs per-entity), which a rich-output tool would benefit from.

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 tool takes zero parameters and the schema is an empty object, so there is no parameter meaning to add. Baseline 4 applies; the description correctly implies the tool is parameterless by describing a fixed aggregation scope.

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 (聚合/aggregate) and resource (风险信号/risk signals) and enumerates the constituent metrics: identity-level distribution, activity distribution, in-custody and duplicate-collateral counts, event counts. This lets an agent tell it apart from raw-list siblings like cvin_events or cvin_identity. It stops short of naming an alternative tool explicitly.

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 only implied: an agent can infer this is the aggregate/overview entry point rather than a per-record lookup, but there is no explicit 'use this when…' statement, no prerequisites, and no named alternative among the 13 siblings. The 200-event threshold note is a behavioral rule, not selection guidance.

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