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

Annotations already declare read-only, idempotent, non-destructive behavior, and the description adds a meaningful behavioral detail: characters without styled equivalents are passed through unchanged. It also clarifies what each style produces, which goes beyond the structured 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?

Three sentences plus a source attribution, with the primary action front-loaded and every sentence contributing information. There is no redundancy with the schema.

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?

For a two-parameter, read-only text transformation with full schema coverage, an output schema, and safety annotations, the description covers the only implicit ambiguity (fallback behavior) and the style semantics. Nothing needed for correct invocation 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?

Schema coverage is 100% for both parameters, so the baseline is 3; the description adds extra value by explaining the visual meaning of each enum value and the fallback behavior for unsupported characters. It does not restate schema descriptions, so it earns above baseline.

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 states a specific verb ('convert'), a resource ('text'), and the exact output domain ('decorative Unicode styles'), with the three style variants enumerated. This makes the tool's function unambiguous and readily distinguishes it from text utilities like case_converter or upside_down_text.

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 communicates clear use context: any time text needs to be restyled in superscript, smallcaps, or fullwidth Unicode forms. It does not name alternative tools or exclusions, so it stops short of explicit routing, but for a simple transformation the intended use is evident.

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