Best AI Security markBest AI Security

Head to head · Checked against vendor sites, September 2026

Onyx Security vs Harmonic Security: AI agent security compared

The verdict

Onyx Security scores higher overall on our weights (7.4 vs 7.1 out of 10). Onyx Security scores higher on tool-call control, identity and audit and breadth; Harmonic Security scores higher on footprint. They tie on visibility, policy and maturity. Neither publishes list prices. Harmonic Security publishes tier names.

Onyx Security

Best for inline control across many AI surfaces

Read the Onyx Security review

Harmonic Security

Best for data protection in everyday AI use

Read the Harmonic Security review

How do Onyx Security and Harmonic Security compare on each criterion?

Endpoint AI control score, editorial assessment 0-10. Edge is the higher score on each row.
CriterionWeightOnyx SecurityHarmonic SecurityEdge
Visibility22%77Tie
Why these scores

Onyx Security: Discovers AI agents across SaaS, cloud, endpoint and code; endpoint inventory detail is lighter than endpoint-first tools.

Harmonic Security: Finds AI tool use across browsers, desktop apps and CLI tools, including local tools on devices.

Tool-call control20%87Onyx Security
Why these scores

Onyx Security: Inspects every prompt, tool call and model response inline.

Harmonic Security: Governs at the MCP layer and tool surface, with permissions for what agents can read, write to and act on.

Policy15%88Tie
Why these scores

Onyx Security: Five enforcement actions: alert, block, mask, steer, or ask a human.

Harmonic Security: Block in real time, warn the employee with context, or log silently; data classification by work intent.

Identity and audit12%76Onyx Security
Why these scores

Onyx Security: Agent identity and access governance is a named solution.

Harmonic Security: Unified governance for humans and agents in Harmonic Command; per-action attribution not detailed.

Footprint13%68Harmonic Security
Why these scores

Onyx Security: Works across endpoint agents, browser extensions, APIs and gateways; the endpoint component is a resident agent or extension.

Harmonic Security: Rolls out through Intune, JAMF, Kandji or Group Policy with no proxy redesign.

Breadth8%96Onyx Security
Why these scores

Onyx Security: Browser AI, coding assistants, desktop agents, cloud workloads and MCP servers, plus agentic red teaming.

Harmonic Security: Centered on data protection in AI use; browser, desktop, MCP and API surfaces.

Maturity10%77Tie
Why these scores

Onyx Security: $113M Series B announced 29 July 2026; SOC 2 Type II and ISO 27001 listed; pricing not published.

Harmonic Security: Publishes named packaging tiers (Explore, Guide, Command) but no prices.

Total100%7.47.1Onyx Security

How we score

How do they deploy, and what do they cost?

Published facts, reviewed September 2026.
AttributeOnyx SecurityHarmonic Security
OwnerNot acquiredNot acquired
How it reaches devicesEndpoint agent, browser extension, API, gatewayIntune, JAMF, Kandji or Group Policy
Deployment detailOnyx says it needs no SDK changes and works across endpoint agents, browser extensions, APIs and gateways. It integrates with Okta, Entra, Splunk and CrowdStrike. On devices this means a resident component, which is why it scores lower on footprint than tools that deploy through EDR or MDM.Harmonic states it rolls out through Intune, JAMF, Kandji or Group Policy, with no proxy redesign and no certificate changes.
PricingContact sales. Onyx Security does not publish pricing.Tiers are published (Explore, Guide, Command), prices are not. Contact sales.

Source: onyx.security · Onyx AI security · Onyx Series B · harmonic.security · Harmonic Command · Harmonic pricing · Reviewed Sep 2026

Which should you choose?

Choose Onyx Security if

  • Your priority matches our designation for Onyx Security: best for inline control across many AI surfaces.
  • Your agents also run in SaaS platforms, cloud workloads or apps you build: Onyx Security scores 9 to 6.
  • You need to evaluate or stop individual tool calls before they run: Onyx Security scores 8 to 7.

Choose Harmonic Security if

  • Your priority matches our designation for Harmonic Security: best for data protection in everyday AI use.
  • You want a light rollout with published deployment detail, ideally through existing EDR or MDM: Harmonic Security scores 8 to 6.

Frequently asked questions

Which is better, Onyx Security or Harmonic Security?

Onyx Security scores higher overall on our weights (7.4 vs 7.1 out of 10). Onyx Security scores higher on tool-call control, identity and audit and breadth; Harmonic Security scores higher on footprint. They tie on visibility, policy and maturity. Scores are editorial assessments from public vendor material, reviewed September 2026.

Do Onyx Security and Harmonic Security publish prices?

No. Neither publishes list prices, so ask both for a quote. Harmonic Security publishes its tier names (Explore, Guide, Command).

Do Onyx Security or Harmonic Security replace EDR?

No. The tools in this guide add control over AI agent actions and work alongside EDR. Onyx Security: Endpoint agent, browser extension, API, gateway. Harmonic Security: Intune, JAMF, Kandji or Group Policy.

Related

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