Create grid style

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

Annotations already cover the safety profile (readOnly=false, idempotent=true, destructive=false), so the bar is lower. The description adds a real constraint not present in annotations: 'Editors: Design only', plus the 'local' scope of the style. It does not cover naming collisions or what the call returns, keeping it short of a 5.

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 dense sentences, each earning its place: definition, consumption path, alternative, then the editor restriction. Information is front-loaded. The jargon-heavy, clause-packed style costs it a point on readability but not on economy.

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 creation tool with no output schema, the description covers what is made, how it is consumed, what differentiates it from the raw-grid sibling, and the permission requirement. Combined with annotations that carry the idempotent/non-destructive profile, an agent has everything needed to invoke it correctly.

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 60%, but the description compensates by giving a worked example for the complex 'grids' entries ('12 columns, 24 gutter, 64 margin') and cross-referencing figma_set_layout_grids for the entry format. The top-level name/grids carry no schema description, so this added context is genuinely valuable, though session/description/idempotencyKey rely on the schema alone.

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 and resource: creating a 'local GRID style — a named layout grid'. It reinforces this with a concrete example ('12 columns, 24 gutter, 64 margin') and explicitly distinguishes itself from the sibling figma_set_layout_grids, which 'sets raw grids on frames instead'. An agent can tell it apart from the other style-creation siblings without opening a schema.

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?

Explains the downstream consumption path ('frames follow via figma_apply_style_to_node { type: "grid" }') and names the alternative tool (figma_set_layout_grids) with the condition that separates them (reusable style vs raw grids). It lacks an explicit 'use this when / not when' framing, but the context is clearly stated.

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