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

With no annotations provided, the description carries the full burden of disclosing behavior. It details the output format (base64 PNG, OHLCV summary), supported intervals, default bar count, and optional indicators. This gives a clear picture of the call's outcome, though error handling or data limitations are not mentioned.

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 core function and output, followed by usage context. Every clause contributes essential information without redundancy.

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 absence of an output schema and annotations, the description covers the key aspects: when to use, what is returned, the interval options, and the default bar count. It omits details about the 'standard image envelope' structure and potential error cases, but for a chart tool this is sufficiently complete to guide correct invocation.

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?

The schema only documents the ticker, so the description adds value by enumerating intervals, specifying the default bar count, and mentioning the RSI/MACD/Bollinger overlays for the indicators parameter. However, it does not explain the exact syntax for the indicators list or the meaning of the bars parameter beyond the default, leaving partial gaps.

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 states the tool produces a candlestick chart with optional technical overlays and returns a base64 PNG plus an OHLCV summary. It explicitly positions itself as the go-to chart tool with 'Call this when the user asks to see a chart,' distinguishing it from the many data-lookup siblings.

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?

It provides an explicit when-to-use directive ('Call this when the user asks to see a chart') and notes that it powers chart-emitting skills. It does not explicitly mention when not to use it or name alternative tools, but the context is unambiguous given the large tool landscape.

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