create_text_style

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

With no annotations, the description carries the full behavioral burden. It usefully discloses upsert semantics and the variable-font interaction between variationSettings and fontStyle, but omits whether an existing style is overwritten or merged, permission/bridge requirements, and any side effects of updating a shared style.

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 tight sentences: the core action is front-loaded, followed by a targeted caveat. No filler, though the variable-font sentence is somewhat dense and could have been split.

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 12-parameter mutation tool with no annotations, no output schema, and 8% schema coverage, the description is too thin. It covers purpose and one parameter nuance but leaves most inputs and all return/side-effect behavior undocumented.

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 only 8%, so the description must compensate for roughly 10 undocumented parameters (fills, fillsHex, fontSize, textCase, lineHeight, letterSpacing, textDecoration, paragraphSpacing, name, fontFamily). It explains variationSettings and its relationship to fontStyle, but leaves the majority of parameters with no added meaning.

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 specific verb+resource ("Create or update a local text style") with a scoping qualifier ("local"). It is clear what the tool does, though it does not explicitly distinguish itself from close siblings like set_text_style, apply_text_style, or create_typography_scale.

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 "create or update" phrasing implies upsert behavior, so the agent can infer it is used to author a style rather than apply one. However, there is no explicit when-to-use guidance, no mention of alternatives such as apply_text_style, and no prerequisites stated.

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