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+# Snapshot Secret Scrubber — Working Demo
+
+> **PR:** #977 — `feat(workspace): snapshot secret scrubber (closes #823)`
+> **Source module:** `workspace/lib/snapshot_scrub.py`
+> **What it does:** Strips API keys, auth tokens, and arbitrary subprocess output from workspace memory snapshots before they are serialized for hibernation
+
+---
+
+## What This Demo Shows
+
+Before a workspace serializes its memory for hibernation, every memory entry passes through the scrubber. API keys, bearer tokens, env-var assignments, and high-entropy base64 blobs are redacted. Sandbox-sourced entries (arbitrary subprocess output from `run_code`) are dropped entirely.
+
+This prevents an attacker who obtains a snapshot blob from recovering credentials or secrets that were processed during the agent session.
+
+---
+
+## Runnable Snippet
+
+```python
+from workspace.lib.snapshot_scrub import (
+    scrub_memory_entry,
+    scrub_snapshot,
+    scrub_content,
+    is_sandbox_content,
+)
+
+# 1. Scrub a single memory entry
+entry = {
+    "id": "mem-001",
+    "source": "agent",
+    "content": "ANTHROPIC_API_KEY=sk-ant-xxxx configured for claude-3-5"
+}
+cleaned = scrub_memory_entry(entry)
+print(cleaned["content"])
+# Output: ANTHROPIC_API_KEY=API_KEY [redacted]
+
+# 2. Scrub an entire snapshot before serialization
+snapshot = {
+    "workspace_id": "ws-abc",
+    "memories": [
+        {"id": "mem-002", "source": "agent", "content": "GitHub token: ghp_AbCdEfGhIjKlMnOpQrStUvW"},
+        {"id": "mem-003", "source": "sandbox", "content": "source=sandbox: echo $SECRET"},
+        {"id": "mem-004", "source": "agent", "content": "Bearer 0xdeadbeef used for /api endpoint"},
+    ]
+}
+scrubbed = scrub_snapshot(snapshot)
+print(scrubbed["memories"])
+# Output: 2 entries (sandbox entry dropped entirely, other two scrubbed)
+
+# 3. Just the scrub function directly
+redacted = scrub_content("OPENAI_API_KEY=sk-proj-1234567890abcdef")
+print(redacted)
+# Output: OPENAI_API_KEY=SK_TOKEN [redacted]
+```
+
+---
+
+## Context
+
+**Why it matters:** Memory snapshots are the workspace's serialized state — saved to disk or transmitted for cross-workspace delegation. If the workspace processed an API key during its session, that key must not survive in the snapshot. `snapshot_scrub.py` is the gatekeeper.
+
+**What gets scrubbed:** API key patterns (`sk-ant-`, `sk-proj-`, `ghp_`, `ghs_`, `AKIA…`, `cfut_`, `mol_pk_`, `ctx7_`), bearer token header values, env-var assignments, and high-entropy base64 blobs (33+ chars). Sandbox-sourced entries (`source=sandbox`, `tool=run_code`, `[sandbox_output]`) are dropped wholesale — they can contain arbitrary subprocess output that can't be safely pattern-matched.
+
+**What doesn't change:** Workspace metadata, config fields, and non-secret memory entries pass through unchanged. The scrubber is a pure function — it's unit-tested independently and has no side effects.
+
+---
+
+## Code Reference
+
+| File | What it does |
+|---|---|
+| `workspace/lib/snapshot_scrub.py` | Core module: `scrub_content()`, `scrub_memory_entry()`, `scrub_snapshot()`, `is_sandbox_content()` |
+| `workspace/tests/test_snapshot_scrub.py` | 21 unit tests covering all pattern classes |
+| `workspace/lib/__init__.py` | Module exports |