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

Beyond the readOnlyHint annotation, the description discloses key behavioral traits: all referenced definitions are included, generated value lists are summarized rather than enumerated, and validate_chart is authoritative for validation. It also warns that omitting chart_type returns a much larger result. No contradiction with annotations.

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?

Four sentences, each earning its place: use-case guidance, return scope, parameter behavior, and a caveat about validation authority. The most important instruction is front-loaded. No filler.

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 output schema exists and the tool has only one optional parameter, the description covers everything an agent needs: when to call it, what it returns, how to narrow the result, and its limitation relative to validate_chart. Nothing important is missing.

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?

The single chart_type parameter is fully documented in the schema, and the description adds practical consequence: passing it restricts output to that family's config variants, while omitting it returns every family and is much larger. This goes beyond the schema's description without being verbose.

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 names a specific verb ('Returns') and resource ('JSON Schema for the whole Szum document'), then enumerates the covered sections: config, data, presentation, size, and output. It also distinguishes itself from validate_chart by framing it as the schema-authoring aid, not the validation authority.

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 tells the agent when to use this tool ('before authoring an unfamiliar field') and which sibling not to use ('instead of probing validate_chart for errors'). It also states that validate_chart remains the authority, giving a clear routing rule.

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