diff --git a/assistant/src/__tests__/checker.test.ts b/assistant/src/__tests__/checker.test.ts
index 4ef038fd24..b27c939c63 100644
--- a/assistant/src/__tests__/checker.test.ts
+++ b/assistant/src/__tests__/checker.test.ts
@@ -12,12 +12,14 @@ import {
 import { homedir, tmpdir } from "node:os";
 import { join, resolve } from "node:path";
 import {
+  afterAll,
   afterEach,
   beforeAll,
   beforeEach,
   describe,
   expect,
   mock,
+  spyOn,
   test,
 } from "bun:test";
 
@@ -72,9 +74,19 @@ mock.module("../config/loader.js", () => ({
 // Defaults to null so existing tests see no extra rules, matching the
 // behaviour on a fresh install without a resolved guardian.
 let mockGuardianPersonaPath: string | null = null;
-mock.module("../prompts/persona-resolver.js", () => ({
-  resolveGuardianPersonaPath: () => mockGuardianPersonaPath,
-}));
+
+// Spy on the namespace import rather than using `mock.module`. Bun's
+// `mock.module` is a persistent process-wide override that would clobber
+// every other export (e.g. `ensureGuardianPersonaFile`,
+// `isGuardianPersonaCustomized`) and break unrelated test files
+// (persona-resolver.test.ts) when run in the same bun test invocation.
+// `spyOn` with `mockRestore()` in afterAll restores the original
+// implementation so other test files see the real exports.
+import * as personaResolver from "../prompts/persona-resolver.js";
+const guardianPathSpy = spyOn(
+  personaResolver,
+  "resolveGuardianPersonaPath",
+).mockImplementation(() => mockGuardianPersonaPath);
 
 import {
   check,
@@ -149,6 +161,13 @@ function writeSkill(
   );
 }
 
+// Restore the guardian persona spy at the end of this file's run so
+// subsequent test files (e.g. persona-resolver.test.ts) see the real
+// implementation when they import from the module namespace.
+afterAll(() => {
+  guardianPathSpy.mockRestore();
+});
+
 describe("Permission Checker", () => {
   beforeAll(async () => {
     // Warm up the shell parser (loads WASM)
diff --git a/assistant/src/__tests__/persona-resolver.test.ts b/assistant/src/__tests__/persona-resolver.test.ts
index a8ecc6555a..3385cff766 100644
--- a/assistant/src/__tests__/persona-resolver.test.ts
+++ b/assistant/src/__tests__/persona-resolver.test.ts
@@ -114,12 +114,12 @@ describe("resolveGuardianPersonaPath", () => {
 
 describe("ensureGuardianPersonaFile", () => {
   test("writes the template when the file is missing", () => {
-    const slug = "sidd.md";
-    const filePath = join(mockWorkspaceDir, "users", slug);
+    const userFile = "sidd.md";
+    const filePath = join(mockWorkspaceDir, "users", userFile);
 
     expect(existsSync(filePath)).toBe(false);
 
-    ensureGuardianPersonaFile(slug);
+    ensureGuardianPersonaFile(userFile);
 
     expect(existsSync(filePath)).toBe(true);
     const content = readFileSync(filePath, "utf-8");
@@ -133,15 +133,15 @@ describe("ensureGuardianPersonaFile", () => {
   });
 
   test("is a no-op when the file already exists (does not clobber)", () => {
-    const slug = "sidd.md";
+    const userFile = "sidd.md";
     const dir = join(mockWorkspaceDir, "users");
-    const filePath = join(dir, slug);
+    const filePath = join(dir, userFile);
     const existingContent = "# Existing user notes\n\n- Likes sparkling water\n";
 
     mkdirSync(dir, { recursive: true });
     writeFileSync(filePath, existingContent, "utf-8");
 
-    ensureGuardianPersonaFile(slug);
+    ensureGuardianPersonaFile(userFile);
 
     const content = readFileSync(filePath, "utf-8");
     expect(content).toBe(existingContent);
@@ -157,20 +157,20 @@ describe("isGuardianPersonaCustomized", () => {
   });
 
   test("returns false for the bare scaffold template (no user edits)", () => {
-    const slug = "sidd.md";
-    const filePath = join(mockWorkspaceDir, "users", slug);
+    const userFile = "sidd.md";
+    const filePath = join(mockWorkspaceDir, "users", userFile);
 
     // ensureGuardianPersonaFile writes the canonical template — the
     // exact bytes that "not customized" accepts.
-    ensureGuardianPersonaFile(slug);
+    ensureGuardianPersonaFile(userFile);
 
     expect(isGuardianPersonaCustomized(filePath)).toBe(false);
   });
 
   test("returns false when the file contains only comment lines", () => {
-    const slug = "sidd.md";
+    const userFile = "sidd.md";
     const dir = join(mockWorkspaceDir, "users");
-    const filePath = join(dir, slug);
+    const filePath = join(dir, userFile);
 
     mkdirSync(dir, { recursive: true });
     writeFileSync(
@@ -183,9 +183,9 @@ describe("isGuardianPersonaCustomized", () => {
   });
 
   test("returns true when the file has user-authored content", () => {
-    const slug = "sidd.md";
+    const userFile = "sidd.md";
     const dir = join(mockWorkspaceDir, "users");
-    const filePath = join(dir, slug);
+    const filePath = join(dir, userFile);
 
     mkdirSync(dir, { recursive: true });
     writeFileSync(
diff --git a/assistant/src/contacts/contacts-write.ts b/assistant/src/contacts/contacts-write.ts
index 812381573b..528579d2f0 100644
--- a/assistant/src/contacts/contacts-write.ts
+++ b/assistant/src/contacts/contacts-write.ts
@@ -8,6 +8,7 @@
 
 import type { ChannelId } from "../channels/types.js";
 import type { GuardianBinding } from "../memory/channel-verification-sessions.js";
+import { clearCache as clearTrustCache } from "../permissions/trust-store.js";
 import { ensureGuardianPersonaFile } from "../prompts/persona-resolver.js";
 import { canonicalizeInboundIdentity } from "../util/canonicalize-identity.js";
 import { getLogger } from "../util/logger.js";
@@ -98,8 +99,20 @@ export function createGuardianBinding(params: {
   // Seed the per-user persona file so downstream readers (journaling,
   // persona resolution) can rely on `users/<slug>.md` existing on disk.
   // Idempotent: pre-existing customized files are preserved.
+  //
+  // Seeding is restricted to the guardian-creation path only — it must
+  // NOT run from inbound-message upsertContactChannel calls, since the
+  // `users/` directory watcher would fire on every new contact and
+  // evict live conversations.
   if (contact.userFile) {
     ensureGuardianPersonaFile(contact.userFile);
+    // Invalidate the trust rule cache so the dynamic guardian-persona
+    // auto-allow rules from `permissions/defaults.ts` are backfilled on
+    // the next `getRules()` call. Without this, guardians created at
+    // runtime (self-heal paths, first-message-seeds-guardian) wouldn't
+    // get their auto-allow rule until the daemon restarts, and the
+    // model would prompt on its first `file_edit users/<slug>.md`.
+    clearTrustCache();
   }
 
   const now = Date.now();
@@ -193,7 +206,7 @@ export function upsertContactChannel(params: {
       ) ?? params.externalUserId)
     : null;
 
-  const contact = upsertContact({
+  upsertContact({
     id: params.contactId,
     displayName,
     role: params.role,
@@ -218,12 +231,11 @@ export function upsertContactChannel(params: {
     reassignConflictingChannels: !!params.contactId,
   });
 
-  // Seed the per-user persona file so downstream readers (journaling,
-  // persona resolution) can rely on `users/<slug>.md` existing on disk.
-  // Idempotent: pre-existing customized files are preserved.
-  if (contact.userFile) {
-    ensureGuardianPersonaFile(contact.userFile);
-  }
+  // NOTE: We intentionally do NOT seed `users/<slug>.md` here. This is the
+  // inbound-message hot path — every new contact (Slack, phone, email, etc)
+  // would otherwise fire the `users/` directory watcher in
+  // config-watcher.ts and evict live conversations. Persona-file seeding
+  // is the sole responsibility of `createGuardianBinding`.
 
   const contactResult = findContactChannel({
     channelType: params.sourceChannel,
diff --git a/assistant/src/permissions/defaults.ts b/assistant/src/permissions/defaults.ts
index 2d7a9e2baf..457c146410 100644
--- a/assistant/src/permissions/defaults.ts
+++ b/assistant/src/permissions/defaults.ts
@@ -166,8 +166,11 @@ export function getDefaultRuleTemplates(): DefaultRuleTemplate[] {
       }));
     }
   } catch {
-    // Guardian may not exist yet; rules will be emitted on the next
-    // template build once the guardian contact is created.
+    // If guardian resolution fails at default-rule computation, the rule
+    // will be missing until the trust cache is invalidated and rebuilt.
+    // Runtime guardian-creation paths invalidate the cache via
+    // `clearTrustCache()` in `contacts-write.createGuardianBinding` so
+    // that the next `getRules()` call picks up the new auto-allow rule.
   }
 
   const bootstrapDeleteRule: DefaultRuleTemplate = {
diff --git a/assistant/src/prompts/persona-resolver.ts b/assistant/src/prompts/persona-resolver.ts
index d6a55474e1..8732d3f84f 100644
--- a/assistant/src/prompts/persona-resolver.ts
+++ b/assistant/src/prompts/persona-resolver.ts
@@ -237,23 +237,27 @@ export function resolveGuardianPersona(): string | null {
 }
 
 /**
- * Write the guardian persona template scaffold to `users/<slug>.md`
+ * Write the guardian persona template scaffold to `users/<userFile>`
  * when the file does not yet exist. No-op when the file already
  * exists (safe against clobbering user edits).
  *
- * Rejects slugs that fail basename validation (path traversal guard).
+ * @param userFile - A filename (not a bare slug), matching the shape
+ *   of `Contact.userFile` — a basename with a `.md` suffix
+ *   (e.g. `"sidd.md"`). The path traversal guard rejects values that
+ *   are not a clean basename.
+ *
  * Creates the parent `users/` directory if missing.
  */
-export function ensureGuardianPersonaFile(slug: string): void {
-  if (basename(slug) !== slug || slug === ".." || slug === ".") {
+export function ensureGuardianPersonaFile(userFile: string): void {
+  if (basename(userFile) !== userFile || userFile === ".." || userFile === ".") {
     log.warn(
-      { slug },
-      "Guardian persona slug contains path traversal; refusing to write",
+      { userFile },
+      "Guardian persona userFile contains path traversal; refusing to write",
     );
     return;
   }
 
-  const filePath = join(getWorkspaceDir(), "users", slug);
+  const filePath = join(getWorkspaceDir(), "users", userFile);
   if (existsSync(filePath)) return;
 
   mkdirSync(dirname(filePath), { recursive: true });