Playwright MCP

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

Annotations already provide readOnlyHint=true, destructiveHint=false, and openWorldHint=true, indicating this is a safe, read-only operation. The description adds minimal behavioral context beyond this, as it doesn't specify what information is listed (e.g., tab titles, URLs) or any constraints like performance implications. It doesn't contradict annotations, but adds little value.

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 'List browser tabs' is extremely concise and front-loaded, consisting of just three words that directly convey the core action. There's no wasted language or unnecessary elaboration, making it efficient for an AI agent to parse.

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 simplicity (0 parameters, no output schema) and rich annotations, the description is minimally adequate. However, it lacks details on what the output includes (e.g., tab IDs, titles) or usage context, which could be helpful for an agent. The annotations cover safety, but the description doesn't fully compensate for the missing 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?

The input schema has 0 parameters with 100% coverage, so no parameter documentation is needed. The description doesn't add parameter information, which is appropriate here. A baseline of 4 is applied since no parameters exist, and the description doesn't introduce confusion.

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 'List browser tabs' clearly states the verb ('List') and resource ('browser tabs'), making the purpose immediately understandable. However, it doesn't differentiate from sibling tools like 'browser_tab_select' or 'browser_tab_close', which also involve tabs but perform different actions, so it lacks sibling differentiation.

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. For example, it doesn't mention if this is for getting current tab information or all tabs, or how it relates to siblings like 'browser_tab_select'. There's no explicit context or exclusions provided.

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