Security Copilot Agents in Defender XDR: where things actually stand

With RSAC 2026 behind us and the E5 inclusion now rolling out between April 20 and June 30, anyone planning SOC workflows or sitting on a capacity budget needs to get a clear picture of what is GA, what is preview, and what was just announced. The marketing pages tend to blur those lines.

This is my sober look at the current state, with the operational details that matter for adoption decisions.

What is actually shipping right now

The Phishing Triage Agent is GA. It only handles user-reported phish through Defender for Office 365 P2, but for most SOCs that is a meaningful chunk of the L1 queue. Verdicts come with a natural-language rationale rather than just a label, which is the part that determines whether analysts will trust it. The agent learns from analyst confirmations and overrides, so the feedback loop matters more than the initial setup.

There is a setup detail that is easy to miss: the agent will not classify alerts that have already been suppressed by alert tuning. The built-in rule "Auto-Resolve - Email reported by user as malware or phish" needs to be off, and any custom tuning rules that touch this alert type need review. If you skip this, the agent runs on an empty queue and you wonder why nothing is happening.

The Threat Intelligence Briefing Agent is also GA. It produces tenant-tailored intel briefings on a regular cadence. Useful, but lower operational impact than the triage agents.

Copilot Chat in Defender went GA with the April 2026 update. Conversational Q&A inside the portal, grounded in your incident and entity data. This is the lowest-risk way to get value out of Security Copilot and probably where most teams should start.

Public preview, worth watching

The Dynamic Threat Detection Agent is the most technically interesting one. It runs continuously in the Defender backend, correlates across Defender and Sentinel telemetry, generates its own hypotheses, and emits a dynamic alert when the evidence converges. Detection source on the alert is Security Copilot. Each alert includes the structured fields (severity, MITRE techniques, remediation) plus a narrative explaining the reasoning.

For EU tenants the residency point is worth confirming with whoever owns data protection in your org: the service runs region-local, so customer data and required telemetry stay inside the designated geographic boundary.

During public preview it is enabled by default for eligible customers and is free. At GA, currently targeted for late 2026, it transitions to the SCU consumption model and can be disabled.

The Threat Hunting Agent is also in public preview. Natural language to KQL with guided hunting. Lower stakes, but useful for teams without deep KQL expertise on hand.

Announced at RSAC, still preview

Two agents got the headlines in March:

The Security Alert Triage Agent extends the agentic triage approach beyond phishing into identity and cloud alerts. The longer-term direction is consolidating phishing, identity, and cloud triage under a single agent. Rollout is from April 2026, in preview.

The Security Analyst Agent is the multi-step investigation agent. Deeper context across Defender and Sentinel, prioritised findings, transparent reasoning trace. Preview since March 26.

Both look promising on paper, but Microsoft's history of preview features that take a long time to mature is well-documented. I would not plan production workflows around either of them yet.

What you actually get with the E5 inclusion

This is the licensing change most people are dealing with right now. Security Copilot has been part of the E5 product terms since January 1, 2026. Tenant rollout is phased between April 20 and June 30, 2026, with a 7-day notification before activation.

The numbers:

• 400 SCUs per month for every 1,000 paid user licenses
• Capped at 10,000 SCUs per month, which you hit at around 25,000 seats
• Linear scaling below that, so a 3,000-seat tenant gets 1,200 SCUs per month
• No rollover, the pool resets monthly

What is included: chat, promptbooks, agentic scenarios across Defender, Entra, Intune, Purview, and the standalone portal. Agent Builder and the Graph APIs are in. If you also run Sentinel, the included SCUs apply to Security Copilot scenarios there.

What is not included: Sentinel data lake compute and storage. Those still run through Azure on the regular meters. Beyond the included pool you pay 6 USD per SCU pay-as-you-go, with 30 days notice before that mode kicks in.

Practical things worth knowing before activation

A few details that are easy to miss in the docs:

Under System > Settings > Copilot in Defender > Preferences, switch from Auto-generate to Generate on demand. Auto-generate will burn SCUs on incidents nobody is going to look at. Generate on demand gives you direct control.

In the Security Copilot portal workspace settings, check the data storage location and the data sharing toggle. Data sharing is on by default, which means Microsoft uses interaction data for product improvement. If your compliance position does not allow that, change it before agents start running. Changing it requires the Capacity Contributor role.

Agent runs are not equivalent to the same number of analyst chat prompts. A triage agent processing fifty alerts in one run consumes meaningfully more SCUs than fifty manual prompts on the same data. If you have a high-volume phishing pipeline, model that out before you flip the switch broadly. The usage dashboard in the Security Copilot portal breaks down consumption by day, user, and scenario.

Output quality depends on telemetry quality. Flaky connectors, gaps in log sources, or a high baseline of misconfigured alerts will produce verdicts that match. Connector health monitoring (the SentinelHealth table in Advanced Hunting is a sensible starting point) is a precondition.

The agents only improve if analysts feed the override loop. If your team treats the verdicts as background noise rather than confirming or correcting them, the feedback signal is lost and calibration stays where it shipped. That is a process problem, not a product problem, but it determines whether any of this is worth the SCUs.

A reasonable adoption order

A rough sequence that minimises capacity surprises:

• Copilot Chat in Defender first. Lowest risk, immediate value through natural language Q&A in the investigation context.
• Phishing Triage Agent on a controlled subset, with a review cadence in place. Check the built-in tuning rules first.
• Watch the SCU dashboard for the first month before adding anything else.
• Let the Dynamic Threat Detection Agent run while it is in public preview, since it is default-on and free anyway. Compare its alerts against existing Sentinel detections.
• Security Alert Triage Agent for identity and cloud once the phishing baseline is stable.
• Establish a monthly review covering agent decisions, false-positive rate, SCU cost, and MTTD/MTTR trends.

Technically, agentic triage is moving past phishing into identity and cloud, and the Dynamic Threat Detection Agent represents a genuine attempt at the false-negative problem rather than just another rule engine. Lizenziell, the E5 inclusion removes the biggest barrier to adoption that previously existed.

The risk is enabling everything at once. Agents that nobody reviews are agents that consume capacity without delivering value, and the SCU dashboard is the only thing that will tell you that is happening. One agent, one use case, a 30-day baseline, then the next one. The order matters more than the speed.