n8n Workflow: Verify AI File Ops with SHA256 & CSV Logs

Verify AI file-operation claims with SHA256 and CSV evidence—automatically

This n8n workflow audits an AI agent’s claimed file operations by checking the local filesystem for existence, symlink safety, SHA256 integrity, and timestamp accuracy—then logs clear PASS/FAIL evidence to a CSV for accountability.

What this workflow does

• Runs manually or via Execute Workflow: start it yourself with sample claims or trigger it from another n8n workflow that sends claim items.
• Applies shared settings to each claim: injects allowed root folder, evidence CSV path, default time window, and a maximum file size to hash.
• Validates path safety: ensures the target path stays within the allowedRoot and refuses symlinks to prevent unsafe access.
• Handles deleted claims: confirms that the file is missing when a claim indicates it was deleted.
• Checks create/modify claims: reads file metadata, computes a SHA256 hash only if the file is under the size limit, and optionally compares it to an expected SHA256.
• Verifies timestamps: checks whether the file’s last-modified time falls within the claim’s time window around the claimed timestamp.
• Writes audit results: outputs PASS/FAIL rows (including reasons) to a CSV, adding headers if needed and appending to the on-disk evidence log.

Use cases

• Auditing AI agent file ops: prove that an agent created/modified/deleted the correct files.
• Security and compliance checks: prevent symlink-based escapes and verify integrity with SHA256.
• Operational QA for SaaS operators: maintain an evidence trail for automation runs.

Technical details

• Required configuration: set NODE_FUNCTION_ALLOW_BUILTIN=crypto,fs,path so the Code node can compute SHA256 and read filesystem metadata.
• n8n file access restrictions: configure N8N_RESTRICT_FILE_ACCESS_TO and set allowedRoot and evidenceCsvPath inside that allowed area.
• Workflow nodes used: set, code, sticky note, manual trigger, read/write file, execute workflow trigger.