chrome-devtools-mcp-mux

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

The annotations indicate readOnlyHint=false, which aligns with the description's 'Start' action implying a write operation. The description adds valuable behavioral context beyond annotations by specifying the tool's purpose (finding performance issues, Core Web Vitals) and expected outcomes (improving page load speed), though it doesn't detail side effects like resource consumption or trace duration limits.

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 front-loaded with the core purpose in the first sentence and uses a second sentence to clarify usage context. Both sentences are essential, with zero wasted words, making it highly efficient and well-structured.

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 (performance tracing with three parameters) and lack of output schema, the description provides sufficient context on what the tool does and when to use it. However, it doesn't explain what the trace output contains or how to interpret it, leaving some gaps for an agent without output schema.

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?

With 100% schema description coverage, the input schema fully documents all three parameters. The description adds no parameter-specific information beyond what the schema provides, so it meets the baseline of 3 for adequate but not enhanced parameter semantics.

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 specific action ('Start a performance trace') on a specific resource ('selected webpage') and distinguishes its purpose from sibling tools like 'performance_analyze_insight' and 'performance_stop_trace' by focusing on initiating trace collection rather than analysis or stopping.

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 explicitly states when to use this tool ('Use to find frontend performance issues, Core Web Vitals... and improve page load speed') and the input schema provides critical guidance on when to use alternatives ('Navigate the page to the right URL using the navigate_page tool BEFORE starting the trace if reload or autoStop is set to true'), clearly differentiating from 'navigate_page'.

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