chrome-devtools-mcp-mux

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

The annotations only indicate readOnlyHint=false, which suggests this is a write/mutation operation. The description adds some behavioral context by specifying what metrics are included/excluded, but doesn't disclose important behavioral traits like whether this tool triggers page reloads, how long audits take, what happens with output files, or authentication requirements. With minimal annotations, the description carries more burden but provides only moderate additional behavioral insight.

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 extremely concise with just two sentences that efficiently communicate the tool's purpose, scope limitations, and alternative tool. Every word earns its place, and the information is front-loaded with the core functionality stated first.

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 (3 parameters, no output schema, readOnlyHint=false annotation), the description provides good context about what the tool does and what it doesn't do. However, it lacks information about return values (since there's no output schema) and doesn't fully address behavioral implications of a non-readOnly operation. The description is mostly complete but has some gaps in behavioral transparency.

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 schema already documents all three parameters thoroughly. The description doesn't add any parameter-specific information beyond what's in the schema. According to scoring rules, when schema coverage is high (>80%), the baseline is 3 even with no param info in the description.

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 tool's purpose with specific verbs ('Get Lighthouse score and reports') and resources ('accessibility, SEO and best practices'), and explicitly distinguishes it from sibling tools by excluding performance audits and naming the alternative tool 'performance_start_trace'.

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 explicit guidance on when to use this tool ('for accessibility, SEO and best practices') and when not to use it ('This excludes performance'), and names the specific alternative tool for performance audits ('performance_start_trace'), offering complete usage context.

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