diff --git a/README.md b/README.md
index 8e19b8a..22f501a 100644
--- a/README.md
+++ b/README.md
@@ -37,7 +37,9 @@ npm test           # Vitest
 - **Theming & fonts** — custom chart themes with a visual Theme Builder, a curated font roster,
   and your own uploaded font faces.
 - **Local-first** — your library lives in the browser (IndexedDB); offline-capable and installable
-  (PWA), with import/export for backup and transfer. No account, no server.
+  (PWA), with import/export for backup and transfer. No account, no server, no AI — with no
+  backend to send it to, your library stays on your device, so it's safe for confidential work
+  from the first chart.
 
 ## Status
 
diff --git a/SOUL.md b/SOUL.md
index 2eae5a2..388e957 100644
--- a/SOUL.md
+++ b/SOUL.md
@@ -28,8 +28,10 @@ data lives in one place and the specs stay lean.
 ### 1. Local-Only by Default
 
 Everything runs in the browser. Snippets, datasets, and settings never leave the machine.
-No accounts, no uploads, no tracking. The only outbound requests are user-created
-URL-dataset fetches.
+No accounts, no uploads, no tracking, and the app contacts no third party on its own —
+including an AI model. The only outbound requests are user-created URL-dataset fetches.
+Because your work stays on the machine, confidential and work data are safe in Astrolabe
+from the first chart.
 
 ### 2. Vega-Lite Native, Not Vega-Lite Hidden
 
@@ -71,6 +73,9 @@ clever.
 - **Not a collaboration platform.** No multi-user, no sync, no comments. Import/export
   moves data between machines.
 - **Not a server app.** No backend, no rendering service, no account system.
+- **Not an AI tool.** No model authors, edits, or critiques charts, and nothing is sent to
+  one. The chart builder's recommendations are deterministic and rule-based, computed
+  locally — chosen over an LLM so results are explainable and nothing leaves the machine.
 
 ## Technical Philosophy
 
diff --git a/docs/exploration/README.md b/docs/exploration/README.md
index 6fe272f..5575452 100644
--- a/docs/exploration/README.md
+++ b/docs/exploration/README.md
@@ -15,3 +15,4 @@ snapshots, not live numbers.
 - `chart-builder-enhancement-scope.md` — consolidated Tier-B → Tier-C forward plan for the Chart Builder.
 - `chart-theming-scope.md` — chart theming plan and slice breakdown.
 - `monetization-and-sync-exploration.md` — monetization + BYO-cloud-sync direction memo.
+- `ai-augmentation-exploration.md` — why Astrolabe stays AI-free, and the key-storage security analysis behind it.
diff --git a/docs/exploration/ai-augmentation-exploration.md b/docs/exploration/ai-augmentation-exploration.md
new file mode 100644
index 0000000..6ce8d2b
--- /dev/null
+++ b/docs/exploration/ai-augmentation-exploration.md
@@ -0,0 +1,53 @@
+# AI Augmentation — Exploration
+
+> **Status:** Exploration, not a commitment. Captured 2026-06-27 from a strategy
+> conversation. The conclusion is folded into [`SOUL.md`](../../SOUL.md) (_Local-Only by
+> Default_ and _Not an AI tool_); this memo keeps the _reasoning_ — including the security
+> analysis behind rejecting browser-stored keys — so a future "should we add AI?" session
+> doesn't re-derive it.
+>
+> **Question:** Most tools shipping in 2026 carry some AI/LLM augmentation. Should
+> Astrolabe?
+>
+> **Short answer:** No — and the user benefit, not purity, is the reason. With no server,
+> no account, and no AI, nothing the user makes is handled by a third party, so Astrolabe
+> is safe for confidential and work data from the first chart. "Everyone ships AI in 2026"
+> is the weakest possible reason to add it: ubiquity makes AI table-stakes noise, not
+> differentiation, and a tool that demonstrably keeps your data on your machine is
+> differentiated _because_ it resists the trend.
+
+---
+
+## 1. Where AI would genuinely fit, if ever
+
+Two spots where Vega-Lite is actually painful and rules can't help but a model could:
+natural-language authoring (NL → spec) and explaining/decoding the editor's opaque
+validation errors. The obvious third — "recommend a chart from my data" — is **already
+solved deterministically** by the Chart Builder's rule-based inference, and the rule-based
+version is better here because it's explainable and runs locally. So the genuine surface is
+narrow.
+
+## 2. Why browser-stored BYO keys were rejected
+
+The only AI model consistent with "no server, no account" is bring-your-own-key, called
+direct browser → provider (never proxied through a server we run, which would put us back in
+the data-custody business). The blocker is key storage:
+
+- A browser has **no secure vault for a secret you must read back**. localStorage,
+  IndexedDB, cookies — all readable by any same-origin JS, devtools, and extensions. Client
+  encryption only helps if the unlock secret isn't _also_ stored, i.e. a passphrase typed
+  each session; a key kept beside its ciphertext is theater.
+- The dominant threat is therefore **same-origin script execution (XSS)**, and Astrolabe is
+  unusually exposed to it: it renders arbitrary user specs through vega-embed, whose
+  expression evaluator and data loader are a real script-execution / exfiltration surface.
+  Holding a secret in that origin upgrades any spec-driven bug from "annoying" to "steals
+  the user's key." **Introducing a stored secret raises the threat level of the whole app,
+  the chart renderer included** — the opposite of what the privacy posture exists to do.
+- The one mitigant: LLM keys are revocable and spend-cappable, so the blast radius is "bill
+  abuse until you rotate it," not data loss. That's why the industry tolerates browser BYOK
+  at all — but it doesn't undo the origin-coupling above.
+
+**If AI is ever revisited:** the only acceptable form is a **session-only** key (held in
+memory, never persisted, re-entered each session) called browser → provider direct, with the
+core staying fully functional and offline for anyone who never engages it. Persisting the
+key is the specific part that compromises the posture.
diff --git a/index.html b/index.html
index a598cb9..4d4e95a 100644
--- a/index.html
+++ b/index.html
@@ -6,6 +6,10 @@
     <link rel="mask-icon" href="/icon-mono.svg" color="#0e7490" />
     <link rel="apple-touch-icon" href="/apple-touch-icon.png" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <meta
+      name="description"
+      content="A local-first studio for Vega-Lite charts. Author specs as JSON, see them render live, and keep a searchable library in your browser. No account, no server, no AI — with no backend to send it to, your data stays on your device, so confidential work is safe here from the first chart."
+    />
     <title>Astrolabe — a local Vega-Lite studio</title>
   </head>
   <body>
diff --git a/src/app/components/AboutModal.tsx b/src/app/components/AboutModal.tsx
index 8b9ca42..6e57c74 100644
--- a/src/app/components/AboutModal.tsx
+++ b/src/app/components/AboutModal.tsx
@@ -4,7 +4,7 @@
  * Rendered inside ModalShell — no backdrop, close button, or focus trap here;
  * the shell owns all of that (docs/architecture/03 → Layer 3). This component
  * is pure content: app identity, keyboard shortcuts (§01D), privacy posture
- * (SOUL.md — local-only, no accounts, no telemetry), and acknowledgements of
+ * (SOUL.md — local-only, no accounts, no telemetry, no AI), and acknowledgements of
  * the projects Astrolabe is built on and shaped by.
  */
 
@@ -74,10 +74,15 @@ export function AboutModal() {
         <h3 className={styles.heading}>Privacy</h3>
         <p className={styles.body}>
           Astrolabe runs in your browser. Your snippets, datasets, and settings are stored locally
-          on your device — there&rsquo;s no server to send them to.
+          on your device — there&rsquo;s no server to send them to. Work that has to stay
+          confidential is safe here.
         </p>
         <ul className={styles.list}>
           <li>No account or sign-in.</li>
+          <li>
+            No AI. No model authors, edits, or critiques your charts, and nothing is sent to one.
+            The chart builder&rsquo;s suggestions are computed locally from your data.
+          </li>
           <li>
             The app itself runs no analytics or tracking. Its host (Cloudflare) records standard,
             aggregate traffic like any web server — not your library or the charts you build, which
diff --git a/src/landing/Landing.tsx b/src/landing/Landing.tsx
index 8d448b2..d8488de 100644
--- a/src/landing/Landing.tsx
+++ b/src/landing/Landing.tsx
@@ -598,16 +598,18 @@ export function Landing(): ReactNode {
             Your charts are <b>yours.</b>
           </h2>
           <p className={styles.creedLede}>
-            Astrolabe runs in your browser, and what it makes is ordinary Vega-Lite JSON — read it,
-            edit it in other tools, or take it elsewhere whenever you want.
+            Astrolabe runs in your browser, and your charts and data stay there — no account, no
+            server, no AI behind it to send them to — so work that has to stay confidential is safe
+            here from the first chart. And what it makes is ordinary Vega-Lite JSON: read it, edit
+            it in other tools, or take it elsewhere whenever you want.
           </p>
           <div className={styles.creedGrid}>
             <div>
               <span className={styles.creedKey}>private</span>
               <h3>Local to your browser</h3>
               <p>
-                Charts, data, and themes are saved in this browser, and it keeps working offline
-                once installed.
+                Charts, data, and themes are saved in this browser and nowhere else — there is no
+                server behind Astrolabe to receive them. It keeps working offline once installed.
               </p>
             </div>
             <div>