ChangeWatch — Semantic Change Detector

ChangeWatch compares two versions of webpage or text content and tells you what actually changed in meaning.

Instead of returning a noisy line-by-line diff, ChangeWatch uses AI to identify changes that could affect a decision, workflow, customer, business, or software agent.

It returns a clean structured JSON report that can be used directly in automations, monitoring workflows, AI agents, data pipelines, and other applications.

What ChangeWatch detects

ChangeWatch is designed to identify meaningful changes such as:

• Prices, fees, and costs
• Availability and inventory
• Dates, deadlines, and schedules
• Requirements and eligibility rules
• Policies and obligations
• Product or service specifications
• Quantities, limits, and thresholds
• Status changes
• Important added or removed statements

It attempts to ignore changes that do not materially affect meaning, including formatting, whitespace, navigation changes, tracking IDs, boilerplate, and reordered content.

How to use it

Provide an older version and a newer version.

Each version can be supplied as either:

• Pasted text
• A public webpage URL

You can also provide optional guidance in the What changes matter? field to focus the comparison on something specific, such as pricing, inventory, deadlines, policy language, or technical specifications.

ChangeWatch will return fields including:

• changed
• importance
• summary
• changes
• recommended_action
• confidence

Each individual change can include the previous value, new value, importance, change type, and an explanation of why it matters.

Example

Older version:

Pro plan costs $19 per month and includes 10 projects.

Newer version:

Pro plan costs $29 per month and includes unlimited projects.

ChangeWatch can identify both the price increase and the change from a 10-project limit to unlimited projects instead of simply reporting that the sentences are different.

Built for automation

ChangeWatch produces structured JSON, making it useful for:

• AI agents
• Competitive monitoring
• Pricing intelligence
• Compliance monitoring
• Product monitoring
• Procurement workflows
• Policy tracking
• Automated alerts
• Research pipelines

If the two normalized inputs are identical, ChangeWatch skips the AI analysis and immediately returns that no meaningful change occurred.

Important limitation

ChangeWatch currently compares two versions supplied by the caller. It does not yet maintain historical webpage snapshots itself.

For recurring monitoring, your workflow should save the previous version or snapshot and provide it again with the newest version on the next run.

Output

One successful comparison produces one dataset item containing the semantic change report and metadata about the comparison.