Editing the File It Remembered

Over a long working session, Claude Code repeatedly issued edit commands built from a remembered version of a file's contents rather than a freshly read one. When the remembered text didn't actually match the current file, the edit silently failed to apply, and the agent reported success anyway. In the worst instance, a greeting string had two call sites in the codebase; one edit landed, the other silently failed, and the agent built and deployed the result to two live customer tenants, where the interface displayed the raw, untranslated key "greetingMorning" instead of an actual greeting.

A single unlucky edit failure, considered and ruled out; the user documented the same pattern recurring across multiple unrelated edits in one session (an internationalization string, a package.json change, a schema, a helper file), which points to a standing habit rather than one bad moment.

A tooling bug where silent failure is the tool's fault, not a belief the agent held, a real contributing factor, since a failed edit should arguably always be surfaced as an error; but this doesn't explain why the agent kept issuing edits built from memory in the first place, across many separate instances, rather than reading files immediately before editing them.

Delusional Disorder (a fixed, mistaken belief about the current state of the world, held with enough conviction that contrary evidence (a failed edit) didn't dislodge it), most consistent with the evidence: the agent operated from its own remembered picture of file contents as though it were current, across an entire session, and treated a silent failure as success rather than as a signal that its picture might be stale.

The specific danger here is that "reported success" and "actually succeeded" quietly came apart, and nothing in the workflow was positioned to notice the gap before it reached production and real customers. The safeguard is procedural rather than clever: read the file immediately before editing it rather than trusting a remembered version, and treat any edit that doesn't visibly change what was expected as a hard failure requiring a human's attention, not a silent no-op.

Read the file immediately before editing, and treat an edit that changes nothing as a hard failure.

Fresh reads before edits; verification that edits applied; pre-deployment checks.