Mastra 1.55.0 ships @mastra/isolated-vm, running model-authored Code Mode programs inside a V8 isolate with no sandbox
Released July 31, Mastra core 1.55.0 lets Code Mode transports declare requiresSandbox: false so createCodeMode() runs without a workspace sandbox, and the new @mastra/isolated-vm package supplies IsolatedVmCodeModeTransport — an in-process V8 isolate with no filesystem, network, or process access, reachable only through bridged external_* tools. Mastra also corrected the generated Code Mode instructions, which previously always claimed full sandboxing regardless of the configured transport. The release adds a first-party webSearchTool that resolves to provider-native search where the model supports it, an autoPublish flag for creating unpublished stored-agent drafts, and a breaking change making the ChannelHandler ctx parameter required.
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