An LLM that edits or overwrites a file it never read is acting on hallucinated
contents. This plane-2 ToolCallRule blocks it: dispatching on FILE_WRITE (covers
file_write and file_edit), a write to a path that exists on disk but was not
file_read earlier this session is BLOCKED. A brand-new file passes — you can't
read what doesn't exist, and creating is legitimate.
- ReadFilesProjection folds the session's file_read events (request + completion,
so a failed read doesn't count) into the set of paths read, mirroring
EgressAllowlistProjection; threaded into ToolCallAssessmentInput.sessionReadPaths
via SessionOrchestrator.resolveSessionReadPaths.
- Read paths and the write target are both resolved through the probe (toRealPath),
so spelling differences and symlinks can't dodge the gate.
- The orchestrator already feeds a block's rationale back as a tool result, so the
agent reads the file and retries; the rejected-event reason now carries that
rationale too (specific audit trail instead of a generic string).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
kami
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