Candlestick Chart

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, which cover the major behavioral traits (non-destructive, idempotent, safe). The description adds no further behavioral context (e.g., authentication, rate limits, output format), but also does not contradict the annotations. The baseline score is appropriate given the annotations carry the transparency burden.

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?

The description is two sentences, front-loaded with the primary action and type, followed by supported data and themes. No unnecessary words; concise and efficient. Every sentence adds value.

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?

Given the rich input schema (86% coverage) and clear annotations, the description adequately covers the tool's purpose and data requirements. However, it omits the return type (e.g., rendered chart as HTML/image), which could aid the agent in understanding the output. Still, the description is largely complete for a chart rendering tool.

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?

With 86% schema description coverage, the input schema already provides detailed descriptions for most parameters, including the data array, theme presets, and options. The description only adds general context ('Provide date/OHLC data... Supports themes') without enriching specific parameter meanings. It meets the baseline for high-coverage schemas.

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 clearly specifies the tool renders an interactive candlestick or OHLC financial chart, distinguishing it from other chart types. It explicitly mentions the data format (date/OHLC) and use cases (stock prices, crypto, forex), which is specific and differentiating from sibling tools like render_line_chart or render_bar_chart.

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 implies the tool is for financial time-series data (stock, crypto, forex) but does not explicitly state when to use it versus alternatives or when not to use it. No exclusions or comparisons are provided, leaving the agent to infer appropriate usage from the name and description alone.

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