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

Annotations declare readOnlyHint=true and openWorldHint=false, and the description aligns with that by describing a generation action with a URL as deliverable, not a system mutation. It adds the crucial instruction to always return the URL, and explains preservation behavior when a URL is passed. This goes beyond what annotations provide.

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 description is moderately long but every sentence serves a purpose: listing sets, explaining usage modes, and highlighting the deliverable. It is front-loaded with the core function. It could be slightly tightened, but it avoids fluff.

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 8 parameters and no output schema, the description effectively covers what the tool returns (URL and summary) and how to handle the URL param. It also explains the 'auto' selection mechanism. An agent has enough context to invoke it correctly without missing critical information.

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%, so all parameters are described in the schema. The description adds value by explaining the 'auto' semantics for set/style/weight/corners, and gives concrete meaning for corners ('sharp = corporate/precise, rounded = friendly'). This enriches the schema without redundancy.

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 the specific verb and resource: 'Pick an icon set and generate icon sizing tokens (xs–2xl + stroke width).' It also lists the available sets and the deliverable (URL and summary). This clearly distinguishes it from sibling tools like generate_shape_tokens or generate_motion_tokens.

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 explains two usage paths: select a specific set or provide style preferences for a recommendation. It also clarifies the behavior of the 'set' parameter with 'auto', and notes that modifying an existing URL only changes this tool's section. It does not explicitly exclude other tools, but the context is clear enough.

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