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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description contributes the 'cost: free' signal, which is genuinely useful cost context, but says nothing about what factors are returned, freshness, or rate behavior beyond that.

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 compact sentence, front-loaded with the resource and followed by the key parameter and cost note; nothing is wasted. The bracketed 【行情】 tag is minor clutter but does aid categorization.

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 simple two-parameter read tool with full schema coverage and annotations, the basics are covered. However, with no output schema, the description gives no indication of the shape or granularity of returned factor data, leaving an agent unable to predict results.

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%, with both symbol and limit documented in the schema including an example value (BTCUSDT). The description only restates that symbol is the trading instrument, adding no new meaning such as supported symbol formats or what limit defaults to, so the baseline 3 applies.

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 verb+resource (查询…市场因子数据) and clarifies the factor domain with 技术/宏观因子, so an agent knows this is factor data rather than price quotes. It does not explicitly contrast itself with near siblings like platform_market_quote or platform_market_ticker, so it falls short of a 5.

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?

There is no statement of when to use this tool versus alternatives, no prerequisites, and no exclusions. The 【行情】 tag only hints at the market-data category; an agent must infer the choice between this and the quote/ticker/overview siblings.

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