visual_check

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

With no annotations, the description fully carries the burden. It discloses default behavior (saves to disk, returns path), the effect of return_image=true (image content block), the required ROBOTMCP_SCREENSHOT_MODE, and graceful degradation on failure. This is rich and actionable.

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 long but every sentence earns its place. It is front-loaded with the core action and then covers options, environment, and compatibility. The structure is logical and not repetitive, though slightly dense.

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 no output schema and no annotations, this description is near-complete: it covers purpose, usage scenarios, return types, environmental requirements, supported libraries, and failure behavior. An agent would have enough context to invoke it correctly.

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 coverage is 0%, so the description must compensate. It thoroughly explains return_image (default false, mode requirements) and implies filename through 'saves the screenshot to disk'. session_id is left inferred, but overall it adds significant meaning to otherwise bare parameters.

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 states a specific verb and resource: 'Capture a screenshot of the current UI for VISUAL validation'. It explicitly distinguishes the tool's use case (checks DOM/ARIA can't do) from other tools. This makes it easy to differentiate from siblings.

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?

Provides explicit when-to-use guidance by listing scenarios like 'canvas/image text, layout/overlap, obscured elements, color, charts' and directs to 'Call get_locator_guidance(library="visual")' for more. It also implies not to use when DOM/ARIA checks suffice.

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