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

Annotations already declare the mutation profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false), and the description adds useful context beyond them: mode=record writes one record, mode=query aggregates and returns total_units plus by_metric grouping. It stops short of saying what happens to duplicate records or whether the write is reversible.

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?

Purpose is front-loaded, followed by a compact mode-by-mode breakdown and the usage condition. The trailing Example mostly repeats the schema's examples block, which is the one redundant sentence.

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 four-parameter, fully schema-documented tool with no output schema, the description covers the write payload and the query return shape. Only the aggregation semantics (per-actor totals, by_metric units) and record duplication behavior could be more explicit.

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 100%, so all four parameters are already documented in the schema, which sets the baseline at 3. The description restates actor/metric/units meanings and maps them to record mode, but adds little syntax or validation detail beyond the schema.

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 (记录/查询 用量计量) and clearly splits behavior into the two modes of the single tool. It does not, however, distinguish itself from the closely related settlement.ledger / settlement.account / audit.record siblings named in the tool set.

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 an explicit usage context: 当多 Agent 协作需要计量各方资源消耗、或做任务结算/分账时使用. That is a usable when-to-use signal, but it names no alternative tool and no exclusion (e.g., when to prefer settlement.ledger for the ledger entry itself).

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