Playwright MCP

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

The description adds minimal behavioral context beyond annotations. Annotations already declare destructiveHint=true and readOnlyHint=false, indicating mutation capability. The description confirms this with 'close' action but doesn't add meaningful context about what gets destroyed (tab state, unsaved data), authentication needs, or rate limits. No contradiction with annotations exists.

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 perfectly concise with a single, front-loaded sentence that lists all four actions. Every word earns its place with zero redundancy or unnecessary elaboration. The structure immediately communicates the tool's scope without preamble.

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 (four distinct actions, destructive operations) and rich annotations but no output schema, the description is minimally adequate. It covers the basic purpose but lacks guidance on usage context, behavioral details, or return values. The annotations help but don't fully compensate for the description's gaps in a multi-action tool.

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 fully documents both parameters. The description adds no parameter-specific semantics beyond implying the four action values. It doesn't explain index usage nuances or default behaviors beyond what's in the schema. Baseline 3 is appropriate when schema carries the full parameter documentation burden.

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 (list, create, close, select) and resource (browser tab). It distinguishes from siblings by focusing on tab management rather than navigation, interaction, or monitoring. However, it doesn't explicitly differentiate from close-related siblings like browser_close.

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 no guidance on when to use this tool versus alternatives. It doesn't mention when to prefer browser_close for closing browsers versus this tool for closing tabs, or when to use browser_navigate versus creating a new tab. No explicit when/when-not statements or alternative tool references are included.

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