Waterfall Chart

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

Annotations already declare read-only and idempotent behavior. Description adds valuable behavioral detail about auto-inferring bar types (add/sub/total) when omitted, which is beyond what annotations provide.

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?

Two concise sentences front-load the essential purpose and key behavior (auto-inference). No wasted words; every sentence earns its place.

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 moderate complexity (7 parameters, no output schema), the description covers the core functionality well. Lacks guidance on when to use this vs. other chart types, which is a gap for an agent selecting from 30+ siblings.

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 good descriptions for each parameter. The description adds minimal extra meaning (e.g., 'What drove the change?' concept) but doesn't significantly enhance understanding beyond the schema.

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 the tool renders a waterfall chart, explains its visual purpose ('cascading bars showing how individual items add up or subtract'), and mentions auto-inference of bar types. This effectively distinguishes it from other chart tools.

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?

Description implies usage for showing additive/subtractive contributions but does not explicitly state when to choose waterfall over other chart types like bar chart or funnel chart. Missing context cues from the extensive sibling list.

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