Fancy text (Unicode styles)

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

Annotations already cover the safety profile (readOnly, idempotent, not open-world), and the description adds substantive behavior the agent cannot get elsewhere: Latin-only substitution, pass-through of other scripts and emoji, partial coverage for some styles (capitals/symbols only), and a 20,000-character cap. That is exactly the extra context this dimension rewards.

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 useful constraints are front-loaded in a single dense block, but roughly half the text is a verbatim restatement of the 28-value enum, which the schema already provides. Trimming that list would make the definition tighter without losing anything an agent needs.

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?

Covers behavior, limits, script scope, and per-style quirks thoroughly for a simple two-parameter transform. The only minor gap is that it doesn't say what the response looks like (presumably an object of style→text when no style is given), and there is no output schema to fall back on.

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 100% and the style enum already lists all 28 values with descriptions, so the schema carries the parameter semantics. The description's re-enumeration of the same styles adds no information beyond the enum; the only real addition, omit-for-all, is also already in the schema's style description.

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?

States a concrete verb and resource ("Restyle text with Unicode look-alike characters") plus the intended output domain (bios and posts) and the style count. An agent can immediately distinguish this from siblings like text_case or text_clean, which transform case/whitespace rather than substituting Unicode glyphs.

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?

"for bios and posts" gives a clear context, and the description explicitly explains the omit-style branch ("Give one style, or none to get every style"). It does not explicitly contrast with text_case/text_clean, which an agent might confuse it with, so no exclusion guidance.

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