AI Prompt Security for Law Firms
Law firms face a specific challenge with AI tools. The value of tools like ChatGPT is highest when given real context — but providing real context means including client names, matter details and confidential instructions. That tension is where prompt security begins.
Ventrin is a Chrome extension that scans and sanitises employee prompts locally in the browser before they are sent to ChatGPT, Claude, Gemini or Copilot. When sensitive content is detected, Ventrin warns the employee, rewrites the prompt automatically, or blocks the send — depending on your team's policy. Sensitive data never leaves the device unintentionally. Admins see every risk event in a central dashboard.
Why law firms need prompt-level AI security
Solicitors and legal staff have always been careful with client data in email and document form. The same discipline has not yet been built into AI tool use. When a fee earner asks ChatGPT to draft a letter, write a chronology, or summarise a document, they often include the client's name, matter reference and confidential context without thinking.
This is not a malicious act. It is a habit gap. The risk is real: client data processed by a third-party AI model may appear in training data, be stored in service logs, or create a data breach if the provider suffers a security incident. Professional obligations under confidentiality rules apply regardless of the medium.
Full client names, company names and matter references included as context in AI prompts.
Legal advice, strategy notes and counsel instructions pasted into AI tools for summarisation.
Witness statements, contract drafts and correspondence copied into prompt boxes.
Client addresses, dates of birth, contact details and financial information used as context.
Opposing party details, expert witness names and court filing content included in prompts.
How Ventrin protects client confidentiality in AI tools
Ventrin scans prompts before they are sent to ChatGPT, Claude or any browser-based AI tool. It detects client identifiers, matter references, personal data and privileged context using on-device detection.
When a risk is found, Ventrin rewrites the prompt — removing the client's name, replacing specific figures with generalised terms and stripping references that could identify a matter. The intent of the prompt is preserved. The client's confidential details are not sent.
For prompts that contain credentials or material that should not be generalised, Ventrin blocks the send entirely. Admins receive an event log for every flagged interaction.
Key Ventrin features for this use case
Recognises personal names, company names and matter references as potential client identifiers.
Flags file numbers, case codes and internal matter references used as prompt context.
Detection and rewriting happens on the device. Sensitive content does not pass through Ventrin servers.
Set stricter rules for fee earners who handle high-risk matters. Admins can adjust policies per team.
Every flagged prompt is recorded. Useful for supervision compliance, data audits and incident review.
Covers ChatGPT, Claude, Gemini, Copilot and other browser-based AI tools from a single extension.
Legal prompt confidentiality table
Filter by risk type to see common legal use cases and how Ventrin handles each one.
| Legal use case | Unsafe prompt example | Risk category | Ventrin action | Safer output |
|---|---|---|---|---|
| Contract summary | Summarise the key obligations in the Patterson Consulting / Nexus Digital SLA, signed 14 March 2026. | Client data | Sanitised | Summarise the key obligations in this commercial SLA, including service levels, payment terms and breach provisions. |
| Client email rewrite | Rewrite this update email to be more concise. It is for Sarah Brennan at Marchfield Group regarding the planning appeal at Lot 7B. | Client data | Sanitised | Rewrite this client update email to be more concise. Keep the key milestones and next steps. Maintain a professional tone. |
| Chronology creation | Create a chronology from these notes. They relate to the Hargreaves dispute. We believe the breach occurred on 12 Jan when they stopped paying rent on Unit 4. | Privileged | Sanitised | Create a chronology from these dispute notes. The key event is an alleged breach on a specific date. Structure events in date order with brief descriptions. |
| Matter note summary | Summarise these file notes from the Wang v. Alderton matter. Key issue is whether the NDA dated 9 Feb was validly executed. | Client data | Sanitised | Summarise these file notes. The key issue is whether a non-disclosure agreement was validly executed. Identify arguments for and against valid execution. |
| Witness statement | Clean up this witness statement from David Henley, DOB 22/07/1971, 14 Burford Lane, Oxon OX18 4PZ. | Personal data | Blocked | This prompt was blocked. Witness statements containing named individuals, dates of birth and home addresses cannot be processed by external AI tools. |
| Billing note | Make this time entry more professional: "Call with Marchfield Group re: appeal. Discussed strategy and QC involvement. 2.5 hours." | Client data | Sanitised | Make this time entry more professional: "Telephone conference with client re: appeal strategy. Reviewed counsel involvement and next steps. 2.5 hours." |
Built for teams that cannot afford a data incident
Local-first detection
The scanning model runs in your browser, not on our servers. Sensitive content never leaves the device for analysis.
No data egress
Ventrin does not receive, store or process your team's prompt content. Only risk event metadata is logged.
Configurable policy controls
Warn, sanitise or block based on content type and team role. Full control over how the extension behaves.
Admin event logs
Every flagged event is recorded with risk type, action and timestamp. Provides the audit trail your compliance process needs.
Protect your team's AI use from the browser
Ventrin deploys as a Chrome extension. No proxy, no network change, no IT project. Most teams are protected on the same day.
Frequently asked questions
Ventrin does not assess whether content is legally privileged in the strict legal sense. It detects patterns associated with client identifiers, named individuals, matter references and sensitive document types. Whether that content is privileged is a legal determination. Ventrin's role is to prevent it leaving the browser unintentionally.
Ventrin is built with smaller teams in mind. It deploys as a browser extension with no infrastructure changes. A sole practitioner or a team of five can be up and running in a day. There is no minimum team size.
Ventrin helps you implement the technical controls that support compliance with SRA rules on confidentiality and data protection. It is not a compliance platform and does not constitute legal advice. Firms should review their AI use policies with their compliance lead or professional indemnity insurer.
Ventrin runs as a Chrome extension and can be installed on any Chrome browser. For firm-managed devices, it can be distributed via enterprise Chrome management. Personal devices require individual installation. Firms should consider their BYOD policy alongside Ventrin deployment.
Yes. Ventrin's policy engine supports team-level and role-level configurations. A firm can apply tighter controls to specific practice groups, for example blocking rather than sanitising on matters involving litigation or regulatory proceedings.
Ventrin works with all major browser-based AI tools including ChatGPT, Claude, Gemini and Microsoft Copilot. Coverage extends to other tools that operate through a browser interface. The extension intercepts the prompt before it is sent, regardless of which tool is open.
Let your team use AI without leaking sensitive data.
Join legal and professional teams already using Ventrin to protect their AI use. Browser-based, locally detected, fast to deploy.