render_chart_url

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

No annotations are provided, so the description carries the full burden. It discloses that the tool returns a 'stable URL' from a CDN, which is useful behavioral context. However, it lacks details on permissions, rate limits, URL expiration, or error handling, which are important for a tool generating external resources.

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 front-loaded with the core purpose in the first sentence, followed by usage guidelines and a note on inputs. Every sentence earns its place with no wasted words, making it highly efficient and well-structured.

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 complexity (7 parameters, no annotations, no output schema), the description is reasonably complete for guiding usage. It clarifies the tool's purpose and when to use it, but lacks details on output format (e.g., URL structure, expiration) and error scenarios, which could be important for integration.

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 0%, so the description must compensate. It adds value by noting 'Same inputs as render_chart,' implying parameters are consistent with a known sibling tool. However, it doesn't explain specific parameters like 'type' enums or 'datasets' structure, leaving significant gaps in parameter understanding.

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: 'Render a chart and return a CDN URL instead of image bytes.' It specifies the action (render), resource (chart), and output format (CDN URL), and distinguishes it from sibling tools by noting it returns a URL rather than image bytes and referencing 'render_chart' as having the same inputs.

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 explicitly states when to use this tool: 'Use this when you need a stable URL to embed in HTML, email, or pass to another tool.' It provides clear context for usage (embedding, email, passing to other tools) and distinguishes it from alternatives by implying 'render_chart' returns image bytes instead.

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