读取已落盘市场快照

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

No annotations are provided, so the description carries the full burden. It discloses the data source (market_snapshot.db) and that it returns the most recently persisted snapshot rather than live data, which is useful. However, it does not address what happens when no snapshot has been persisted yet or how stale the data may be.

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?

A single sentence that front-loads the action, names the source database, specifies the data scope, and states the intended use case. Every clause earns its place with zero filler.

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?

The tool is simple: one optional parameter, an output schema (so return values need no description), and a clear use case. The description covers source, recency semantics, and intent. The only notable gap is the empty-cache edge case, but for a straightforward cache-read tool the description is otherwise complete.

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 100% — the single 'table' parameter is fully documented with its allowed values (broad_market / capital_flows / all), so the schema does the heavy lifting. The description's mention of '大盘指数/资金面' loosely maps to those values but adds no new syntax or format details, matching the baseline of 3.

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 (读取/read), a concrete resource (market_snapshot.db), and the data content (大盘指数/资金面快照). The qualifier '已落盘/最近一次落盘' distinguishes this from live-fetch siblings like market_broad_snapshot or capital_flows_snapshot, though it does not name them 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?

The phrase '前端待机页秒开用' gives a clear usage context: use this when the standby page needs an instantly-available cached snapshot. However, it does not explicitly state when NOT to use it or name alternatives such as market_broad_snapshot or capital_flows_snapshot for live data needs.

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