Playwright MCP Server

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

Annotations provide readOnlyHint=false, destructiveHint=true, and openWorldHint=true. The description adds behavioral context by specifying the four possible actions, including destructive ones (close). It doesn't contradict annotations and provides useful operational details beyond what annotations alone convey, though it could mention rate limits or side effects.

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 (one sentence) and front-loaded with all key information. Every word earns its place by listing the four core actions. No redundant or verbose language is present.

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 (multiple actions, destructive operations) and lack of output schema, the description is minimally adequate. It covers the core functionality but doesn't explain return values, error conditions, or how actions differ behaviorally. Annotations help with safety profile, but more context would be beneficial for 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?

Schema description coverage is 100%, with clear parameter documentation. The description doesn't add meaning beyond the schema's enum values for 'action' or details for 'index'. It implies the tool's multi-action nature but doesn't explain parameter interactions or edge cases. Baseline 3 is appropriate given high schema coverage.

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 the resource (browser tab). It distinguishes from siblings like browser_close (which closes the browser, not tabs) and browser_navigate (which navigates within a tab), but doesn't explicitly contrast with all sibling tools. The description is more specific than the title 'Manage tabs'.

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 use browser_tabs versus browser_close (which closes the entire browser) or browser_navigate (for tab navigation). No context about prerequisites, timing, or exclusions is provided.

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