Mcp-DOM

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get_dom_state

Reconstruct a full DOM snapshot for any past timestamp or event ID via delta replay to diagnose UI disappearances and layout changes.

Instructions

Reconstruct the complete DOM snapshot at an arbitrary timestamp or event ID using checkpoint delta replay.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "sessionId": "<sessionId>"
    },
    "name": "get_dom_state"
  }
}

Input Schema

Name	Required	Description
`format`	No	Output format (default: html)
`eventId`	No	Target event ID
`sessionId`	Yes	Session ID
`timestamp`	No	Target timestamp in milliseconds

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.0.0Sep 1, 2026

TDQS

A3.7/5.0

Behavior3/5

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 discloses the checkpoint delta replay mechanism, which is a meaningful behavioral trait, but it does not mention performance costs, limitations of the reconstructed snapshot, or whether the operation has side effects (though it appears read-only).

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

Conciseness5/5

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

A single sentence contains the core purpose, key input concept (timestamp/event ID), and the method (checkpoint delta replay). Every word contributes; there is no filler or redundancy.

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?

The description sufficiently covers what the tool does and the method, and the schema handles parameter documentation. However, it does not explain what happens when neither timestamp nor eventId is provided (e.g., does it default to latest state?), nor does it give any guidance on interaction with the many sibling tools, making the definition incomplete for an agent deciding how to invoke it correctly.

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

Parameters3/5

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

Schema description coverage is 100%, so the schema already documents all parameters. The description adds the concept of 'arbitrary timestamp or event ID', aligning with timestamp and eventId, but does not provide additional semantic detail beyond the schema's property descriptions.

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

Purpose5/5

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

The description uses a specific verb ('Reconstruct') with a precise resource ('complete DOM snapshot') and a distinctive mechanism ('checkpoint delta replay'). This clearly differentiates the tool from live snapshot, node-specific, and diff-focused siblings.

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?

The description implies historical reconstruction at a specified timestamp or event ID, which provides context for when the tool is appropriate. However, it does not explicitly state when to prefer this tool over alternatives like get_live_dom_snapshot or get_dom_subtree, nor does it mention any exclusions.

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