MCP-Midscene

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

No annotations are provided, so the description carries the full burden. It describes the core behavior (switching focus to a tab) but lacks details about potential side effects (e.g., whether this triggers page reloads, visibility changes, or requires specific browser states), error conditions, or response format. It adds basic context but misses deeper behavioral traits.

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 two sentences with zero waste: the first states the purpose, and the second provides essential usage guidance. It's appropriately sized and front-loaded with the core functionality.

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 (single parameter, no output schema, no annotations), the description is reasonably complete: it explains what the tool does, how to use it with a sibling tool, and the parameter purpose indirectly. However, it lacks details on behavioral aspects like error handling or effects, leaving some gaps for a mutation 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%, so the schema already fully documents the single parameter (tabId). The description doesn't add any additional meaning about the parameter beyond what the schema provides (e.g., format examples, validation rules, or source context beyond the sibling tool reference). Baseline 3 is appropriate when schema does the heavy lifting.

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 specific action ('Switches the browser's focus') and resource ('to the tab specified by its ID'), distinguishing it from sibling tools like midscene_get_tabs (which finds tabs) and midscene_navigate (which navigates pages). It provides a precise verb+resource combination.

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 explicitly states when to use this tool ('Use midscene_get_tabs first to find the correct tab ID'), providing a clear prerequisite and alternative tool reference. This gives the agent direct guidance on the workflow sequence.

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