Create Design System

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

Annotations already carry readOnlyHint=true, idempotentHint=true, and destructiveHint=false, lowering the bar. The description adds genuinely useful behavioral context: outputs are platform-dependent ('CSS/Tailwind or SwiftUI/Compose'), one deliverable is conditional ('a stock-region fact if the seed sits in indigo/violet/purple'), and 'ready-to-paste' clarifies the tool returns artifacts for the user to apply rather than persisting state. No contradiction with the readOnly annotation since the generation is computational, not a state mutation.

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 usage rule is front-loaded at the end of the description and the headline is punchy, but the opening sentence is a single dense run-on enumerating ten artifacts with nested parentheticals ('named defaults to leave, the type pairing as a decision, one signature move, and a stock-region fact...'). The marketing phrase 'THE one-call foundation' adds emphasis but little functional value, and the wall-of-text structure makes scanning harder than it needs to be.

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?

With no output schema, the description bears the return-value burden and largely carries it: it lists every generated artifact, explains the conditional and platform-dependent behaviors, and names the workflow that follows. The only real gap is that the response envelope (structure/format of the returned design system) is unspecified, though the artifact list makes the return content predictable for a 4-parameter generation tool.

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% — all four parameters have meaningful descriptions with examples and defaults, so the baseline is 3. The description reinforces the relationship (brand_color + vibe + platform drive the whole output) and notes platform 'picks icon set and token output,' but adds no syntax or format details beyond what the schema already provides.

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: 'Turn a brand color + product vibe + platform into a complete, coherent design-system starter' and enumerates concrete deliverables (direction card, tokens, type scale, elevation ramp, components, build checklist). It differentiates from the many design siblings by positioning itself as the 'one-call foundation' and naming get_component_recipe and get_design_roadmap as the follow-up tools.

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?

Explicitly instructs: 'Use this FIRST when someone says design/build me a website/app to lay the foundation, then get_component_recipe for each component and get_design_roadmap for the full process.' This gives an agent a clear decision rule, sequential ordering, and named alternatives without leaving anything to inference.

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