css_set_property

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

The phrase 'live modification' conveys that changes apply to the current page state, which is a useful behavioral detail given the lack of annotations. However, it does not disclose side effects, persistence, handling of multiple matching selectors, or preconditions, leaving significant gaps for a mutation tool.

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 a single, clear sentence that front-loads the action and resource. It is appropriately sized without unnecessary verbosity, achieving high efficiency even though it could benefit from more contextual detail elsewhere.

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 simple tool with three well-documented parameters and no output schema, the description covers the core action and the live-modification aspect. However, it lacks important edge-case information such as behavior with non-existent selectors or multiple matches, making it minimally adequate but incomplete.

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 input schema already provides complete descriptions for all three parameters (selector, property, value), so the description adds no semantic value beyond the schema. The baseline score of 3 applies because schema coverage is 100% and the description does not introduce ambiguity.

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 clearly identifies the action (Set) and the resource (a CSS property on an element), with 'live modification' specifying the runtime nature. This distinguishes it from read-only siblings like css_computed_style and css_matched_rules.

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?

No guidance is provided on when to use this tool versus alternatives such as css_computed_style or css_force_pseudo. The description only states what it does, leaving the agent to infer appropriate usage from context, with no exclusions or alternative tool mentions.

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