MCP Accessibility Scanner

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, indicating a safe, read-only operation that may return variable data. The description adds no behavioral context beyond what annotations provide, such as whether it returns tab titles, URLs, or order, or if there are rate limits. It doesn't contradict annotations, so a baseline score is appropriate.

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—just three words—and front-loaded with the core action. Every word earns its place by directly conveying the tool's function without any fluff or redundancy, making it highly efficient for quick understanding.

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 low complexity (0 parameters, no output schema) and rich annotations (readOnlyHint, openWorldHint), the description is minimally complete. It states what the tool does but lacks details on output format or usage context. For a simple list operation, this is adequate but leaves gaps that could be filled with a bit more information.

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 details, which is acceptable here. A score of 4 reflects that the description is adequate given the lack of parameters, though it could briefly note the absence of inputs for clarity.

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 action (list) and resource (browser tabs), making the purpose immediately understandable. It distinguishes from siblings like browser_tab_close or browser_tab_new by focusing on listing rather than modifying tabs. However, it doesn't specify if it lists all tabs or just active ones, keeping it from a perfect score.

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 prerequisites (e.g., needing an open browser), exclusions, or comparisons to siblings like browser_tab_select for navigation. This lack of context leaves the agent to infer usage based on the name alone.

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