Unverified50% confidenceFactExact time
F-Stop is a Portal prequel project that Valve once developed but ultimately cancelled; it is not an early version of Portal 2, but rather an independent concept built around a different core mechanic.
1
Sources
50%
Confidence
Long-term
Relevance
11/1/2026
First Seen
Sources
Related Entities
Related Claims
UnverifiedAccording to the leakers, the playable F-Stop build is an "almost complete" version whose core flow can be run, though it cannot be ruled out that some parts remain unfinished or require temporary patches.68% similarUnverifiedA complete playable build of the cancelled Portal prequel project F-Stop has leaked, and the community has rebuilt it into a near-complete playable form.55% similarUnverifiedIn v2.1.286, Stop and Escape in the VS Code extension now only end the current turn; background agents continue running and can be stopped individually from the agent map.53% similarUnverifiedIn C++ asynchronous RPC, if a completion callback may still run after cancellation, freeing request state too early introduces use-after-free vulnerabilities.53% similarUnverifiedAI SDK 2.0.81 introduces a new completion reason, interrupted, for provider streams, used for streams that end without receiving a completion signal.52% similar
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