OmniSnap MCP

Focus and photograph

focus_element

Idempotent

Focuses a selected page element and returns a screenshot so you can verify focus rings and catch missing keyboard-accessibility indicators.

Instructions

Focuses an element and returns a screenshot. Use it to check focus rings, which are the most commonly missing accessibility feature and are invisible in an ordinary capture.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "focus_element"
  }
}

Input Schema

Name	Required	Description	Default
`element`	No	A number from the most recent annotate_interactive on this tab. Easier and safer than retyping a selector.
`selector`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.2.3Nov 11, 2026

TDQS

B3.4/5.0

Behavior4/5

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

Annotations declare the operation non-read-only but idempotent and non-destructive; the description adds the genuinely useful trait that focus rings are invisible in an ordinary capture, explaining why this tool exists. It does not say whether focus persists after the call or how the screenshot is returned, but the essential behavior is disclosed.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences with the outcome front-loaded and the rationale second. The mild advocacy phrasing about the most commonly missing accessibility feature still earns its place by justifying the tool's existence.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description should say more about the returned screenshot, and it should clarify the zero-required-parameter situation where both element and selector are optional. Adequate for a small utility, but an agent still has to guess at parameter interplay.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is only 50%: element carries a description tying it to annotate_interactive, but selector is bare. The description adds nothing about either parameter, and notably does not explain whether element and selector are alternatives or whether both may be supplied.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

"Focuses an element and returns a screenshot" gives a specific verb plus resource and, crucially, states the output, which separates it from plain capture_element. It is clear but never explicitly contrasts itself with the sibling tools that also produce captures.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

"Use it to check focus rings" supplies one concrete when-to-use condition, which is more than most definitions offer. There is no when-not guidance and no mention of when capture_element or capture_page would be the better pick.

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