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Runtime guardrails and AI firewalls · #14 by signal score

Prompt Security

AI firewall and usage control for employee AI tools, coding assistants, and homegrown AI apps: blocks adversarial prompts, scrubs sensitive outputs, and keeps a log of agent actions. Acquired by SentinelOne in 2025.

Acquired by SentinelOne, announced 2025-08-05, closed 2025-09-05 ($160.2M, per SEC filing). Now sold as Prompt Security, part of the SentinelOne Singularity Platform.

16Signal score / 100
Capital
6/35
Product
10/25
Standards
0/20(not yet assessed)
Momentum
0/20

Identity primitives

Agent as a first-class identityNot checked
On-behalf-of token exchangeNot checked
Cross App Access (ID-JAG)Not checked
Asynchronous human approval (CIBA)Not checked
MCP authorization conformanceNot checked
Fine-grained authorizationNot checked
Short-lived, secretless credentialsNot checked
Token vaultNot checked
Kill switchNo public claim found
Per-action audit chainNo public claim found

Company

HQ: IL
Funding: $23M disclosed

Sources

  1. SentinelOne: Prompt Security (vendor, accessed 2026-09-23)
  2. Prompt Security (vendor, accessed 2026-09-23)
  3. SentinelOne to acquire Prompt Security to advance GenAI security (press-release, accessed 2026-09-23)
  4. M&A spotlight shifts to Lasso, Aim, and Pillar after SentinelOne's $250M Prompt deal (trade-press, accessed 2026-09-23)
  5. SentinelOne, Inc. Form 10-K for the fiscal year ended January 31, 2026 (sec, accessed 2026-09-23)

Last verified 2026-09-23.