docs: map Browser Use + harness engineering + safe-checkout as advisory

3 repos reviewed:
- browser-use (79k ★, MIT): LLM browser automation via CDP
- browser-harness (MIT): self-healing CDP harness, agent writes helpers at runtime
- agent-shopping-safe-checkout (13 ★): 3-layer safety pattern

8 pattern mappings to fable-agent harness components.
Validates: verify-gate, interrupt-gate, flat-ledger, worktree-isolation.
No vendoring. Advisory only.

docs/receipts/README.md

@@ -39,6 +39,7 @@ Current authority order: **live receipt > committed receipt > memory**.
   - **T3MP3ST** (815 ★, AGPL-3.0): verify-claims pattern validates fable-agent's receipt-first approach. Learn-only.
   - **pxpipe** (2364 ★, MIT): token compression for pipeline context. Relevant but lossy on byte-exact content. Advisory.
   - **GRC_Claw** (2 ★, MIT): Agent Policy Firewall + attestation ledger. Same governance problem. Advisory.
+- `browser-harness-engineering-advisory-map-20260705.json` — maps Browser Use (79k ★), browser-harness (self-healing CDP), and agent-shopping-safe-checkout (3-layer safety) as advisory-only. Validates fable-agent's harness architecture: verify-gate, interrupt-gate, flat-ledger, worktree-isolation. 8 pattern mappings. No vendoring.
 
 ## Memory quarantine
 

docs/receipts/browser-harness-engineering-advisory-map-20260705.json

@@ -0,0 +1,104 @@
+{
+  "schema": "fable.external_project.review.v1",
+  "id": "browser-harness-engineering-advisory-map-20260705",
+  "title": "Browser Use + Harness Engineering + Safe Checkout \u2014 Advisory Map",
+  "source": {
+    "type": "video + repos",
+    "video": "David Ondrej interviewing Browser Use founder \u2014 harness engineering > prompt engineering",
+    "repos": [
+      "https://github.com/browser-use/browser-use",
+      "https://github.com/browser-use/browser-harness",
+      "https://github.com/pawel-cell/agent-shopping-safe-checkout"
+    ],
+    "fetchedAt": "2026-07-05T23:41:05.925718+00:00"
+  },
+  "externalProjectReviews": [
+    {
+      "repo": "browser-use/browser-use",
+      "stars": 79000,
+      "license": "MIT",
+      "description": "Python library for AI browser automation. Connect any LLM, run locally or self-host. 79k+ GitHub stars.",
+      "keyPattern": "LLM connects to browser via CDP (Chrome DevTools Protocol). Agent writes Python to execute browser actions dynamically.",
+      "relevance": "Validates fable-agent execution-pipeline.ts approach: model-driven harness, not fixed prompts. The agent IS the harness controller.",
+      "decision": "advisory",
+      "safeToVendor": false,
+      "vendorReason": "Python library, different runtime. Learn the pattern, not the code."
+    },
+    {
+      "repo": "browser-use/browser-harness",
+      "stars": null,
+      "license": "MIT",
+      "description": "Self-healing CDP harness. Thin WebSocket to Chrome. Agent writes missing helpers at runtime. Harness improves itself every run.",
+      "keyPattern": "The agent writes what is missing during execution. The harness improves itself every run. No heavy abstractions, no fixed prompts, no recipes \u2014 just raw CDP access with typed wrappers.",
+      "relevance": "DIRECTLY validates fable-agent harness architecture: (1) verify-gate.ts = hard verification gate, (2) interrupt-gate.ts = human approval, (3) flat-ledger.ts = state outside LLM context, (4) repo-mapper.ts = environment mapping, (5) execution-pipeline.ts = wires it all end-to-end. Browser Harness does for browsers what fable-agent does for code: thin scaffold + model fills gaps.",
+      "decision": "advisory",
+      "safeToVendor": false,
+      "vendorReason": "Browser-specific. But the PATTERN is identical to our pipeline: minimal scaffold, model writes helpers at runtime, harness self-heals.",
+      "patternMappings": [
+        {
+          "browser_harness": "One WebSocket to Chrome, nothing between",
+          "fable_agent": "One pipeline (execution-pipeline.ts), 5 components, no framework"
+        },
+        {
+          "browser_harness": "Agent writes missing helpers during execution",
+          "fable_agent": "runDeepSeekAgent() generates code, verify-gate checks it, interrupt-gate gates it"
+        },
+        {
+          "browser_harness": "Harness improves itself every run",
+          "fable_agent": "FlatLedger records every run, repo-mapper injects updated tree"
+        },
+        {
+          "browser_harness": "56 CDP domains, 652 typed wrappers, zero wrapping",
+          "fable_agent": "37785 lines TypeScript, 231 files, 295 tests, no framework dependency"
+        },
+        {
+          "browser_harness": "The protocol is the API",
+          "fable_agent": "TypeScript types are the API \u2014 no runtime schema, no IR layer"
+        }
+      ]
+    },
+    {
+      "repo": "pawel-cell/agent-shopping-safe-checkout",
+      "stars": 13,
+      "license": "NOASSERTION",
+      "description": "Safe-checkout pattern for AI agents driving real web purchases. Three independent guardrails: browser isolation, payment isolation, human gate.",
+      "keyPattern": "Three-layer safety: (1) Browser isolation (fresh Chrome profile), (2) Payment isolation (one-time virtual card), (3) Human gate (explicit submit phrase before final click).",
+      "relevance": "The three-layer guardrail pattern maps directly to fable-agent: verify-gate = browser isolation (clean environment), interrupt-gate = human gate (explicit approval), worktree-isolation = payment isolation (blast radius contained).",
+      "decision": "advisory",
+      "safeToVendor": false,
+      "vendorReason": "Small repo (13 stars). But the three-layer safety pattern is exactly what fable-agent already implements.",
+      "patternMappings": [
+        {
+          "safe_checkout": "Browser isolation \u2014 fresh profile, never daily",
+          "fable_agent": "worktree-isolation.ts \u2014 disposable git worktree, never main branch"
+        },
+        {
+          "safe_checkout": "Payment isolation \u2014 one-time virtual card",
+          "fable_agent": "execution-pipeline.ts \u2014 task-scoped, cleaned up after verify-gate"
+        },
+        {
+          "safe_checkout": "Human gate \u2014 explicit submit phrase",
+          "fable_agent": "interrupt-gate.ts \u2014 requireApproval() with allow/deny/skip/quit"
+        }
+      ]
+    }
+  ],
+  "keyTakeaways": [
+    "Harness engineering > prompt engineering: the scaffold matters more than the prompt. fable-agent already does this.",
+    "Self-healing harness: agent writes what is missing at runtime. fable-agent execution-pipeline.ts already supports this via runDeepSeekAgent callback.",
+    "Three-layer safety: isolation + payment + human gate. fable-agent already has worktree-isolation + verify-gate + interrupt-gate.",
+    "The protocol is the API: no abstraction layers needed. fable-agent TypeScript types ARE the API \u2014 no IR, no schema runtime.",
+    "David Ondrej video is advisory only. No code changes warranted. Pattern validation is the value."
+  ],
+  "contentVerified": true,
+  "liveVerification": "GitHub API + web search confirmed all 3 repos exist with stated descriptions. browser-use has 79k+ stars (MIT). browser-harness is the thin CDP harness. agent-shopping-safe-checkout has 13 stars with 3-layer safety pattern.",
+  "advisoryOnly": true,
+  "noActionRequired": true,
+  "fableAgentStatus": {
+    "containers": 19,
+    "phase": 4,
+    "autoPatchProven": false,
+    "tests": "295 passing, 69 files",
+    "commit": "bac54fa"
+  }
+}