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

The annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful context that the call is free (cost: free), that output is a K-line array, and that limit caps at 299, but says nothing about pagination, timezone, or whether the returned candles are ascending or descending.

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?

It is a single compact sentence chain that puts the resource and the required symbol parameter first, then the optional timeframe and limit, then the return type and cost. It is slightly dense with bracketed tags (【行情】, （cost: free）), but no sentence is wasted.

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 three-parameter read-only market-data tool with no output schema, the definition covers the essentials: what is queried, the valid symbol format, the valid timeframe set, the limit ceiling, what comes back, and that it costs nothing. The remaining gap, such as candle ordering or timezone, is minor for this complexity level.

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%, so the baseline is 3, but the description goes beyond the schema by enumerating the accepted timeframe values (1m/5m/15m/30m/1H/4H/1D). The schema has no enum constraint on timeframe, so this enumeration is genuinely new information that prevents invalid calls.

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 uses a specific verb and resource pair (查询平台行情 K 线 / query platform market candles) and states exactly what is returned (a K-line array for the symbol). It is clearly distinguishable from read-only info siblings like platform_market_ticker and platform_market_overview, but it never names those alternatives, so the differentiation is only implied.

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 by the resource type: an agent can infer this is the tool for OHLC candle series rather than last price or market summary. There is no explicit statement about when to choose this over platform_market_ticker or platform_market_overview, and no exclusions or prerequisites are given.

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