generate_funnel_chart

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

Annotations provide readOnlyHint=true, indicating this is a safe read operation. The description adds value by explaining the chart's purpose (visualizing progressive data reduction) and giving a real-world example, which helps the agent understand the tool's behavioral context beyond just being read-only. However, it does not disclose additional traits like rate limits, authentication needs, or output format details, which would be useful given the lack of an output schema.

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 a single, well-structured sentence that efficiently conveys the tool's purpose and includes a practical example. It is front-loaded with the core functionality and avoids unnecessary details, making it easy for an agent to parse quickly. Every part of the sentence earns its place by clarifying the tool's use case.

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 tool's complexity (6 parameters, nested objects) and rich schema coverage (100%), the description adequately explains what the tool does with a clear example. However, there is no output schema, and the description does not specify the return type (e.g., image URL, chart object), leaving a gap in understanding the tool's output. With annotations covering safety but no output details, the description is moderately complete but could be improved by addressing the output.

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%, so the schema already documents all parameters thoroughly (e.g., data structure, style options, dimensions). The description adds minimal parameter semantics by implying the 'data' parameter should represent sequential stages with reducing values, as in the conversion rate example. This provides some contextual meaning beyond the schema but does not significantly enhance parameter understanding, aligning with the baseline score for high schema coverage.

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's purpose: 'Generate a funnel chart to visualize the progressive reduction of data as it passes through stages.' It specifies the verb ('generate'), resource ('funnel chart'), and provides a concrete example ('conversion rates of users from visiting a website to completing a purchase'), which distinguishes it from sibling tools like generate_bar_chart or generate_pie_chart that serve different visualization purposes.

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 usage context by mentioning 'progressive reduction of data as it passes through stages' and giving an example of conversion rates, suggesting this tool is for visualizing sequential data reduction. However, it does not explicitly state when to use this tool versus alternatives (e.g., when to choose a funnel chart over a waterfall chart or other siblings), nor does it provide exclusions or prerequisites, leaving some ambiguity for the agent.

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