149 issues of the old Brief covered attacks and tools. This is Mandos Brief #1. From here on it covers the market: deals, signals, and what they mean if you build or invest.
Three agent-security startups got bought this week. Not one buyer sells agent security. Kiteworks does file transfer. SecureSky does MDR. Harvey is a legal AI company with no security business at all.
Same week, the biggest cheque went to Cylake. $245M. No product yet. Beta at the end of the year.
That's the market telling you two things at once. Agent security gets absorbed as a feature by whoever already owns the workflow. Platform money goes to platforms. If you sell a standalone agent-security product, your buyer already expects it inside something they pay for.
The week in numbers
- Deals in the window: 6 (3 funding, 3 M&A).
- Disclosed funding: $282.3M
- Largest round: Cylake, $245M Series B, Lightspeed, Picture Capital and Redpoint
- Acquisitions: 3, all undisclosed
- Only on the Mandos platform: 3 pricing changes this week, 2 of them straight off the pricing page
Lowest weekly count in ten weeks. Part of it is a real slowdown after a heavy start to September, and the number will climb a little as the week's deals get confirmed. Every deal with amounts and sources is on the Mandos platform.
Deals that matter
Harvey acquires Guardrails AI. Terms undisclosed. Harvey's fourth acquisition of 2026.
A legal-AI company bought an agent-guardrails startup. The open-source framework gets 250,000 downloads a month. The buyer isn't a security vendor. The buyer is the app. Harvey's agents run legal work for hours at a time, and Harvey decided the guardrails belong inside its own stack, not in someone else's console. Most telling deal of the week.
Kiteworks acquires Bonfy.AI. Undisclosed. CTech estimates tens of millions. Announced 8 September.
Runtime classification for data going into and out of AI agents, folded into a file-transfer platform. Bonfy left stealth with a $9.5M seed in June 2025. Fifteen months from stealth to exit. Feature-sized company, feature-sized price, bought by the company that owns the data flow.