diff --git a/frontend/src/stores/product-assistant.js b/frontend/src/stores/product-assistant.js
index 4e642335c7..0ad509d61d 100644
--- a/frontend/src/stores/product-assistant.js
+++ b/frontend/src/stores/product-assistant.js
@@ -11,10 +11,19 @@ const MAX_DEBUG_LOG_ENTRIES = 100 // maximum number of debug log entries to keep
 const TOOL_POLICIES = ['allow', 'ask', 'deny']
 const isToolPolicy = (p) => TOOL_POLICIES.includes(p)
 const TOOL_CLASSES = ['read', 'write', 'destructive']
-// Fail-safe default when a class has no configured default: read allows, the rest ask.
-const fallbackForToolClass = (cls) => (cls === 'read' ? 'allow' : 'ask')
+// Flow-building changes only touch the editor and nothing runs until the user deploys,
+// so every class starts allowed there. Platform actions act on the account straight
+// away: read allows, the rest ask.
+const fallbackForToolClass = (cls, group = TOOL_GROUPS.FLOW_BUILDING) => {
+    if (group === TOOL_GROUPS.FLOW_BUILDING || cls === 'read') return 'allow'
+    return 'ask'
+}
 // The class defaults a team starts with before the user changes anything.
-const defaultToolDefaults = () => ({ read: 'allow', write: 'ask', destructive: 'ask' })
+const defaultToolDefaults = (group = TOOL_GROUPS.FLOW_BUILDING) => ({
+    read: fallbackForToolClass('read', group),
+    write: fallbackForToolClass('write', group),
+    destructive: fallbackForToolClass('destructive', group)
+})
 // The team whose saved permissions are in effect. Permissions are per team, so every
 // read/write of defaults or preferences is scoped by this id.
 const currentTeamId = () => useContextStore().team?.id || null
@@ -336,7 +345,7 @@ export const useProductAssistantStore = defineStore('product-assistant', {
             const migrated = saved.destructive === undefined && legacyDelete !== undefined
                 ? { ...saved, destructive: legacyDelete }
                 : saved
-            return { ...defaultToolDefaults(), ...migrated }
+            return { ...defaultToolDefaults(group), ...migrated }
         },
         /** The current team's saved per-tool preferences ({ [key]: policy }). */
         teamToolPreferences: (state) => {
@@ -346,7 +355,7 @@ export const useProductAssistantStore = defineStore('product-assistant', {
         defaultForToolClass () {
             return (cls, group = TOOL_GROUPS.FLOW_BUILDING) => {
                 const d = this.teamGroupDefaults(group)[cls]
-                return isToolPolicy(d) ? d : fallbackForToolClass(cls)
+                return isToolPolicy(d) ? d : fallbackForToolClass(cls, group)
             }
         },
         /** This chat session's grant for a tool key, or null if none ('allow'|'deny'). */
@@ -719,7 +728,7 @@ export const useProductAssistantStore = defineStore('product-assistant', {
             const teamId = currentTeamId()
             if (!teamId) return
             const teamDefaults = this.toolDefaultsByTeam[teamId] || {}
-            const groupDefaults = { ...defaultToolDefaults(), ...(teamDefaults[group] || {}), [cls]: policy }
+            const groupDefaults = { ...defaultToolDefaults(group), ...(teamDefaults[group] || {}), [cls]: policy }
             this.toolDefaultsByTeam = {
                 ...this.toolDefaultsByTeam,
                 [teamId]: { ...teamDefaults, [group]: groupDefaults }
diff --git a/test/unit/frontend/stores/product-assistant.spec.js b/test/unit/frontend/stores/product-assistant.spec.js
index 6d32d83863..a270dfb945 100644
--- a/test/unit/frontend/stores/product-assistant.spec.js
+++ b/test/unit/frontend/stores/product-assistant.spec.js
@@ -508,9 +508,23 @@ describe('product-assistant store', () => {
         })
 
         describe('teamGroupDefaults / defaultForToolClass', () => {
-            it('returns the fail-safe defaults when the team has none saved', () => {
+            it('allows every class in flow-building when the team has none saved', () => {
                 const store = useProductAssistantStore()
-                expect(store.teamGroupDefaults(TOOL_GROUPS.FLOW_BUILDING)).toEqual({ read: 'allow', write: 'ask', destructive: 'ask' })
+                expect(store.teamGroupDefaults(TOOL_GROUPS.FLOW_BUILDING)).toEqual({ read: 'allow', write: 'allow', destructive: 'allow' })
+            })
+
+            it('keeps asking for platform writes and destructive actions by default', () => {
+                const store = useProductAssistantStore()
+                expect(store.teamGroupDefaults(TOOL_GROUPS.PLATFORM)).toEqual({ read: 'allow', write: 'ask', destructive: 'ask' })
+                expect(store.defaultForToolClass('write', TOOL_GROUPS.PLATFORM)).toBe('ask')
+                expect(store.defaultForToolClass('destructive', TOOL_GROUPS.PLATFORM)).toBe('ask')
+            })
+
+            it('keeps a class default the user saved as ask', () => {
+                const store = useProductAssistantStore()
+                store.setToolClassDefault(TOOL_GROUPS.FLOW_BUILDING, 'write', 'ask')
+                expect(store.defaultForToolClass('write')).toBe('ask')
+                expect(store.defaultForToolClass('destructive')).toBe('allow')
             })
 
             it('defaultForToolClass reflects a saved class default', () => {
@@ -522,15 +536,15 @@ describe('product-assistant store', () => {
             it('defaultForToolClass falls back per class when nothing valid is stored', () => {
                 const store = useProductAssistantStore()
                 expect(store.defaultForToolClass('read')).toBe('allow')
-                expect(store.defaultForToolClass('write')).toBe('ask')
-                expect(store.defaultForToolClass('destructive')).toBe('ask')
+                expect(store.defaultForToolClass('write')).toBe('allow')
+                expect(store.defaultForToolClass('destructive')).toBe('allow')
             })
 
             it('migrates a pre-rename "delete" default saved before the destructive rename', () => {
                 const store = useProductAssistantStore()
-                store.toolDefaultsByTeam = { [TEAM]: { [TOOL_GROUPS.FLOW_BUILDING]: { delete: 'allow' } } }
-                expect(store.teamGroupDefaults(TOOL_GROUPS.FLOW_BUILDING)).toEqual({ read: 'allow', write: 'ask', destructive: 'allow' })
-                expect(store.defaultForToolClass('destructive')).toBe('allow')
+                store.toolDefaultsByTeam = { [TEAM]: { [TOOL_GROUPS.FLOW_BUILDING]: { delete: 'ask' } } }
+                expect(store.teamGroupDefaults(TOOL_GROUPS.FLOW_BUILDING)).toEqual({ read: 'allow', write: 'allow', destructive: 'ask' })
+                expect(store.defaultForToolClass('destructive')).toBe('ask')
             })
 
             it('prefers an already-migrated "destructive" default over a stale "delete" one', () => {
@@ -572,13 +586,13 @@ describe('product-assistant store', () => {
                     { key: 'write-flow', toolClass: 'write' },
                     { key: 'destructive-flow', toolClass: 'destructive' }
                 ])
-                store.setSessionToolOverride('write-flow', 'allow')
+                store.setSessionToolOverride('write-flow', 'deny')
                 const resolved = store.resolvedToolPermissions
-                expect(resolved.defaults).toEqual({ read: 'allow', write: 'ask', destructive: 'ask' })
+                expect(resolved.defaults).toEqual({ read: 'allow', write: 'allow', destructive: 'allow' })
                 expect(resolved.tools).toEqual({
                     'read-flow': 'allow',
-                    'write-flow': 'allow', // session grant folded in
-                    'destructive-flow': 'ask'
+                    'write-flow': 'deny', // session grant folded in
+                    'destructive-flow': 'allow'
                 })
             })
         })