chrome-devtools-mcp-mux

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

Annotations indicate readOnlyHint=false, implying a mutation, which aligns with 'closes'. The description adds useful behavioral context about the constraint with the last page, but doesn't detail effects like whether the page is destroyed or if changes are saved. With annotations covering the mutation hint, this earns a baseline score for adding some context.

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 two concise sentences with zero waste: the first states the action, and the second provides a critical constraint. Every word earns its place, making it highly efficient and front-loaded.

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?

Given the tool's moderate complexity (closing a page with a constraint), no output schema, and annotations covering mutation status, the description is mostly complete. It could benefit from mentioning what happens post-closure (e.g., focus shifts), but the constraint and purpose are clear, making it adequate for use.

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 has 0 parameters with 100% coverage, so no parameter documentation is needed. The description implies an 'index' parameter indirectly, but since the schema explicitly defines no parameters, this doesn't detract significantly. A baseline of 4 is appropriate for zero parameters.

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 states the action ('closes') and resource ('the page by its index'), making the purpose understandable. However, it doesn't explicitly differentiate from sibling tools like 'select_page' or 'navigate_page' that also interact with pages, which prevents a perfect score.

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 provides clear context on when NOT to use the tool ('The last open page cannot be closed'), which helps avoid errors. It doesn't specify alternatives or when to prefer this over other page-management tools, but the constraint guidance is valuable.

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