HEAD-TO-HEAD · FACTS ONLY
Harmonic vs Zscaler: AI endpoint control facts side by side
Short answer
Harmonic describes 2 of the four product control types on the pages we read and Zscaler describes 1; they differ on on-device control, browser extension, network or SSE proxy and AI or MCP gateway. On decisions, Harmonic describes some control over tool calls and Zscaler does not describe tool-call decisions on the pages we read. We do not score either; the right choice depends on the AI tools people use, your devices, your current stack and whether you block or guide.
By The Device Desk · Endpoint AI Finder · Published 2026-10-11
Desk research from public vendor pages read on 27 September and 11 October 2026. Profiles follow our published method; we did not run the products.
Vendor pages read September and October 2026 · updated 2026-10-13
Where do their controls sit?
- Filled or hatched marker: Harmonic
- Dashed teal ring: Zscaler, described
- DEV Filled marker: described on the product pages we read
- DEV Hatched marker: partly described (another component, a narrower scope, or method not detailed)
- DEV Dashed marker: not in our sources (it may exist; we did not find it)
What are the facts, side by side?
| Fact | Harmonic | Zscaler |
|---|---|---|
| Owner | None | None |
| Positioning | A data protection product for everyday AI use, sold as Explore, Guide and Command, covering browser extensions, desktop apps and CLI tools, MCP gateways and an API. | Zscaler's controls for employee use of generative AI: prompt-level visibility, allow or block by app, DLP blocking across GenAI apps, browser isolation that disables cut, paste and download, and data security for Microsoft Copilot. |
| How it reaches devices | Rolls out through Intune, JAMF, Kandji or Group Policy. Source: Harmonic Security homepage · Read 27 Sep 2026 | Delivered with Zscaler's cloud security service in the network path; endpoint agents are not described on the page we read. Source: Zscaler: Secure the use of generative AI · Read 11 Oct 2026 |
| On-device controlDiffers | Partly describedDeployment options include desktop apps and AI agents, rolled out through device management; the on-device component is not described in detail. Source: Harmonic Security pricing (re-read) · Read 11 Oct 2026 | Not in our sourcesNot described on the pages we read. |
| Browser extensionDiffers | DescribedBrowser extensions are a listed surface, with block, warn or log actions. Source: Harmonic Security homepage · Read 27 Sep 2026 | Not in our sourcesNot described on the pages we read. |
| Network or SSE proxyDiffers | Not in our sourcesNot described on the pages we read. | DescribedSee all input prompts users send to apps, allow or block apps, block sensitive data with DLP across GenAI, and isolate the browser to disable cut, paste and download. Source: Zscaler: Secure the use of generative AI · Read 11 Oct 2026 |
| AI or MCP gatewayDiffers | DescribedMCP gateways are a listed surface, and Harmonic Command governs at the MCP layer and at the tool surface. Source: Harmonic Security: Command · Read 27 Sep 2026 | Not in our sourcesNot described on the pages we read. |
| Names the coding agents it coversDiffers | MatchesThe Guide tier adds desktop AI apps and developer tools, naming Claude Code, GitHub Copilot, ChatGPT Desktop and Microsoft 365 Copilot. Source: Harmonic Security pricing (re-read) · Read 11 Oct 2026 | Not in our sources |
| Decides on a tool call before it runsDiffers | PartlyThe Command tier adds MCP client and server discovery, agent permissions for read, write and execute, and MCP server tool controls. Source: Harmonic Security pricing (re-read) · Read 11 Oct 2026 | Not in our sources |
| Controls what goes into browser AI | MatchesBlock, warn or log on AI use in the browser. Source: Harmonic Security homepage · Read 27 Sep 2026 | MatchesPrompt-level visibility, DLP blocking across GenAI apps, and browser isolation that disables cut, paste and download. Source: Zscaler: Secure the use of generative AI · Read 11 Oct 2026 |
| Rolls out through EDR or device management you runDiffers | MatchesRolls out through Intune, JAMF, Kandji or Group Policy. Source: Harmonic Security homepage · Read 27 Sep 2026 | Not in our sources |
| Can warn or ask instead of only blockingDiffers | MatchesWarn is one of three actions, with block and log. Source: Harmonic Security homepage · Read 27 Sep 2026 | Not in our sources |
| Can block an agent, tool or action | MatchesBlock is one of three actions. Source: Harmonic Security homepage · Read 27 Sep 2026 | MatchesAllow or block GenAI apps, and block sensitive data with DLP. Source: Zscaler: Secure the use of generative AI · Read 11 Oct 2026 |
| Has a watch-only or simulation modeDiffers | MatchesLog is one of three actions, for watching before enforcing. Source: Harmonic Security homepage · Read 27 Sep 2026 | Not in our sources |
| Records who or what took each action | Not in our sources | Not in our sources |
| Also covers SaaS, cloud or homegrown AI | PartlyAn API is listed alongside device surfaces; SaaS or cloud agents are not described. Source: Harmonic Security homepage · Read 27 Sep 2026 | PartlyData security for Microsoft Copilot, including misconfigurations. Source: Zscaler: Secure the use of generative AI · Read 11 Oct 2026 |
| Has a public price or tiers (vendor site or marketplace)Differs | PartlyNames three tiers (Explore, Guide, Command) on its pricing page, without prices. Source: Harmonic Security: pricing · Read 27 Sep 2026 | Not in our sources |
| Built into | None | None |
| Works with | None in our sources | None in our sources |
| Price | Three named tiers (Explore, Guide, Command) with no prices; a full prompt audit log is an add-on on Guide and Command. Source: Harmonic Security pricing (re-read) · Read 11 Oct 2026 | Not published (demo request). Source: Zscaler: Secure the use of generative AI · Read 11 Oct 2026 |
Where do they differ?
- On-device control: Harmonic partly describes it; Zscaler is not in our sources.
- Browser extension: Harmonic describes it; Zscaler is not in our sources.
- Network or SSE proxy: Harmonic is not in our sources; Zscaler describes it.
- AI or MCP gateway: Harmonic describes it; Zscaler is not in our sources.
- Names the coding agents it covers: Harmonic matches; Zscaler is not in our sources.
- Decides on a tool call before it runs: Harmonic partly matches; Zscaler is not in our sources.
- Rolls out through EDR or device management you run: Harmonic matches; Zscaler is not in our sources.
- Can warn or ask instead of only blocking: Harmonic matches; Zscaler is not in our sources.
- Has a watch-only or simulation mode: Harmonic matches; Zscaler is not in our sources.
- Has a public price or tiers (vendor site or marketplace): Harmonic partly matches; Zscaler is not in our sources.
Choose Harmonic if
- Your main risk is employees pasting sensitive data into AI tools and you would rather coach than block
- You manage devices with Intune, JAMF, Kandji or Group Policy
Choose Zscaler if
- You already route traffic through Zscaler and want GenAI controls there
- Your main risk is sensitive data pasted or uploaded into GenAI web apps
Which limits should you check?
Harmonic
- Tier names only, no prices, and the full prompt audit log is an add-on.
- An activity record that separates a person from an agent is not described, and prompt injection protection is listed as coming soon.
Zscaler
- Coding agents, MCP servers and local agent actions are not described on the page we read.
- Warn or ask responses are not described, and no pricing is published.