add_chart_highlight_zone

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

No annotations, but description accurately states it adds a shaded zone to a chart figure and returns an enhanced dict. Does not mention potential side effects, but for chart enhancement this is sufficient.

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?

Three sentences, front-loaded with action, purpose, and return value. No unnecessary words.

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?

Adequately describes the tool's purpose and return. Lacks details on error conditions or figure modification behavior, but acceptable for a chart enhancement tool with output schema.

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 has 100% coverage, so description adds no new parameter details beyond what's in the schema. Baseline score of 3 is appropriate.

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?

Description clearly states it adds a shaded vertical highlight zone to a chart, with specific examples (COVID years, crisis periods). Distinguishes from sibling tools like add_chart_annotation and add_chart_threshold_line.

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?

Provides ideal use cases (crisis periods, policy changes) but does not explicitly say when not to use or mention alternative tools.

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