List Card Builder CSS custom properties

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered by structured data. The description adds the 'unfiltered' nature of the result and the underlying backend call path, which is mildly useful context, but the field-level return detail largely duplicates the existing output schema.

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?

Front-loads the action and scope, then the call path, then the usage condition, then the return contract — a sensible ordering. The field enumeration in the middle is somewhat verbose given an output schema exists, but nothing is padding.

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 parameters and a dedicated output schema, an agent has everything needed to invoke this correctly, and the description supplies the routing context. The only gap is mild redundancy in restating return fields the output schema already defines.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The absence of parameters is implicitly conveyed by the description's list-only framing.

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 ('List') and resource ('registered CSS custom properties') and names the sibling it complements ('card_builder_create_css_custom_property'). An agent can distinguish it from card_builder_list_cards and card_builder_list_style_presets without opening any 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?

Contains an explicit 'Use when:' clause tying the tool to the precondition of registering a new property, and names the alternative sibling tool to call next. This is exactly the when/when-not/alternative structure the dimension rewards.

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