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

With no annotations, the description carries the full burden and does so well: it discloses the output contract (values quoted verbatim with units, missing fields set to null and reported in warnings, no estimation or fabrication), an explicit no-buy/sell-advice constraint, and a three-tier data-source fallback (腾讯 → 新浪 → 东财 push2) surfaced via warnings. It stops short of stating rate limits, latency, or authentication needs.

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?

Front-loaded with the one-line purpose, then clearly labeled sections for output fields, output contract, and data source. Every line earns its place; there is no filler or repetition.

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?

An output schema exists, so return values need not be re-explained, and the description still adds the value-level contract (units, null policy, warnings) that the schema cannot. Input format, output contract, and failure/degradation behavior are all covered, leaving only minor gaps around concurrency or freshness guarantees.

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 0% – the schema only declares code as a bare string – so the description must supply the meaning, and it does: the value is a 6-digit stock code with a concrete example (600519). That is the single most important detail for invoking the tool correctly, though no further format/validation constraints are given.

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?

States a specific resource and action (个股行情快照 = individual stock quote snapshot) and enumerates the return fields, so an agent knows exactly what it produces. It names the associated skill but never contrasts itself with the close sibling market_snapshot, so differentiation from alternatives relies on inference.

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 description tells the agent the required input form (6-digit code, e.g. 600519), which implies when the tool applies. However, it gives no explicit when-to-use/when-not guidance and never points to an alternative such as market_snapshot, so selection between the two is left to the agent.

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