Funnel Chart

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

Annotations already indicate readOnlyHint and idempotentHint true, so the description adds value by explaining the visual behavior (width-proportional bars, conversion percentages). It does not contradict annotations. However, it could mention output format (e.g., image URL) to further aid agent understanding.

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 sentence that conveys the tool's purpose and key visual characteristic without any superfluous information. It efficiently front-loads the purpose.

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 7 parameters and no output schema, the description is somewhat minimal. It covers the type of chart but lacks context on output behavior (e.g., returns chart element or image). The sibling tools are all chart renderers, so the family is clear, but additional details on expected input format or output would improve completeness.

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% with descriptions for all 7 parameters. The description adds minimal extra meaning beyond the schema, such as explaining that data is 'top to bottom' stages. Baseline score of 3 is appropriate as the schema already does the heavy lifting.

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 'Render a funnel chart' with the question 'Where do we lose people?' indicating a specific chart type for conversion analysis. It distinguishes from sibling chart tools by describing width-proportional bars and optional conversion percentages.

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 use for conversion stage analysis but does not explicitly state when to use this tool vs other chart types (e.g., bar or line chart). No exclusions or alternatives are mentioned, leaving the agent without clear context on selection criteria.

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