diff --git a/forge/comms/platformAutomation.js b/forge/comms/platformAutomation.js
index a2e32e6e5d..d5ae7c91f6 100644
--- a/forge/comms/platformAutomation.js
+++ b/forge/comms/platformAutomation.js
@@ -99,14 +99,20 @@ class PlatformAutomationHandler {
                 const user = await this.app.db.models.User.byId(userId)
                 if (user) {
                     const { token } = await this.app.expert.mcp.getOrCreatePlatformToken(user)
-                    const inject = (opts) => this.app.inject({
-                        ...opts,
-                        headers: {
-                            ...opts.headers,
-                            authorization: `Bearer ${token}`,
-                            'x-ff-automation-source': 'expert'
-                        }
-                    })
+                    const inject = (opts) => {
+                        const nonce = this.app.nonceStore.createSourceNonce({
+                            source: 'mcp:expert',
+                            toolName
+                        })
+                        return this.app.inject({
+                            ...opts,
+                            headers: {
+                                ...opts.headers,
+                                authorization: `Bearer ${token}`,
+                                'x-ff-source-nonce': nonce
+                            }
+                        })
+                    }
 
                     const { formatResponse } = require('../ee/lib/mcp/toolLoader')
                     const response = await tool.handler(args, { inject })
diff --git a/frontend/src/components/audit-log/AuditEntry.vue b/frontend/src/components/audit-log/AuditEntry.vue
index f4a7583f69..0cfeb2567d 100644
--- a/frontend/src/components/audit-log/AuditEntry.vue
+++ b/frontend/src/components/audit-log/AuditEntry.vue
@@ -29,8 +29,9 @@
             </div>
         </div>
         <!-- User/Trigger -->
-        <div v-if="entry.trigger.name !== 'unknown'" class="ff-audit-entry-trigger lg:w-36">
-            {{ entry.trigger.name }}
+        <div v-if="entry.trigger.name !== 'unknown'" class="ff-audit-entry-trigger lg:w-36 flex items-center flex-nowrap">
+            <span class="flex-1 text-right">{{ entry.trigger.name }}</span>
+            <span v-if="sourceIcon" v-ff-tooltip:left="sourceLabel" class="flex-0 cursor-help"><component :is="sourceIcon" class="ff-icon-sm ml-1" /></span>
         </div>
         <div v-else class="ff-audit-entry-trigger lg:w-36">
             &nbsp;
@@ -40,7 +41,7 @@
 
 <script>
 
-import { CpuChipIcon, RectangleGroupIcon, UserGroupIcon } from '@heroicons/vue/24/outline'
+import { CommandLineIcon, CpuChipIcon, RectangleGroupIcon, SparklesIcon, UserGroupIcon } from '@heroicons/vue/24/outline'
 
 import ProjectsIcon from '../../components/icons/Projects.js'
 
@@ -67,10 +68,39 @@ export default {
         AuditEntryIcon,
         AuditEntryVerbose,
         ProjectsIcon,
+        CommandLineIcon,
         CpuChipIcon,
         RectangleGroupIcon,
+        SparklesIcon,
         UserGroupIcon
     },
+    computed: {
+        sourceIcon () {
+            if (!this.entry.source) {
+                return null
+            }
+            if (this.entry.source.startsWith('mcp')) {
+                return SparklesIcon
+            }
+            if (this.entry.source === 'api') {
+                return CommandLineIcon
+            }
+            return null
+        },
+        sourceLabel () {
+            const toolName = this.entry.body?.sourceContext?.toolName
+            if (this.entry.source === 'mcp:expert') {
+                return toolName ? `via Expert (Tool name: ${toolName})` : 'via Expert'
+            }
+            if (this.entry.source === 'mcp') {
+                return toolName ? `via MCP (Tool name: ${toolName})` : 'via MCP'
+            }
+            if (this.entry.source === 'api') {
+                return 'via API'
+            }
+            return ''
+        }
+    },
     methods: {
         getApplication (association) {
             return association.ownerType === 'application' ? association : null
diff --git a/frontend/src/stylesheets/components/audit-log.scss b/frontend/src/stylesheets/components/audit-log.scss
index 47d4021943..1248b9615c 100644
--- a/frontend/src/stylesheets/components/audit-log.scss
+++ b/frontend/src/stylesheets/components/audit-log.scss
@@ -60,8 +60,6 @@
 }
 
 .ff-audit-entry-trigger, .ff-audit-entry-time {
-    grid-area: time;
-    display: block;
     color: var(--ff-color-text-subtle);
     overflow-x: hidden;
     white-space: nowrap;
@@ -79,4 +77,4 @@
         grid-template-areas: 'time entry author';
         grid-template-columns: min-content 1fr min-content;
     }
-}
\ No newline at end of file
+}
diff --git a/test/unit/forge/comms/platformAutomation_spec.js b/test/unit/forge/comms/platformAutomation_spec.js
new file mode 100644
index 0000000000..f28e059392
--- /dev/null
+++ b/test/unit/forge/comms/platformAutomation_spec.js
@@ -0,0 +1,160 @@
+const should = require('should') // eslint-disable-line
+const sinon = require('sinon')
+
+const setup = require('../routes/setup')
+
+const FF_UTIL = require('flowforge-test-utils')
+const { PlatformAutomationHandler } = FF_UTIL.require('forge/comms/platformAutomation')
+
+describe('PlatformAutomationHandler', function () {
+    const license = 'eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6ImZkNDFmNmRjLTBmM2QtNGFmNy1hNzk0LWIyNWFhNGJmYTliZCIsInZlciI6IjIwMjQtMDMtMDQiLCJpc3MiOiJGbG93Rm9yZ2UgSW5jLiIsInN1YiI6IkZsb3dGdXNlIERldmVsb3BtZW50IiwibmJmIjoxNzMwNjc4NDAwLCJleHAiOjIwNzc3NDcyMDAsIm5vdGUiOiJEZXZlbG9wbWVudC1tb2RlIE9ubHkuIE5vdCBmb3IgcHJvZHVjdGlvbiIsInVzZXJzIjoxMCwidGVhbXMiOjEwLCJpbnN0YW5jZXMiOjEwLCJtcXR0Q2xpZW50cyI6NiwidGllciI6ImVudGVycHJpc2UiLCJkZXYiOnRydWUsImlhdCI6MTczMDcyMTEyNH0.02KMRf5kogkpH3HXHVSGprUm0QQFLn21-3QIORhxFgRE9N5DIE8YnTH_f8W_21T6TlYbDUmf4PtWyj120HTM2w'
+
+    let app
+    let handler
+
+    function mockClient () {
+        const handlers = {}
+        return {
+            on: (event, callback) => { handlers[event] = callback },
+            emit: function () {
+                const evt = arguments[0]
+                const args = Array.prototype.slice.call(arguments, 1)
+                handlers[evt].apply(null, args)
+            }
+        }
+    }
+
+    function invokeToolCall ({ userId, toolName, args, meta }) {
+        return new Promise((resolve) => {
+            const onSuccess = (result) => resolve({ ok: true, result })
+            const onError = (message, code, err) => resolve({ ok: false, message, code, err })
+            handler.eventHandler(
+                {
+                    userId,
+                    command: 'mcp-call-tool',
+                    data: { name: toolName, input: args || {} },
+                    meta
+                },
+                onSuccess,
+                onError
+            )
+        })
+    }
+
+    before(async function () {
+        app = await setup({
+            license,
+            ai: { enabled: true },
+            expert: { enabled: true }
+        })
+    })
+
+    after(async function () {
+        await app.close()
+    })
+
+    beforeEach(function () {
+        const client = mockClient()
+        handler = PlatformAutomationHandler(app, client)
+    })
+
+    afterEach(function () {
+        sinon.restore()
+    })
+
+    describe('source context nonce injection', function () {
+        it('mints a nonce with source mcp:expert and the correct toolName', async function () {
+            const createSpy = sinon.spy(app.nonceStore, 'createSourceNonce')
+            const tool = handler.findTool('platform_list_teams')
+
+            const res = await invokeToolCall({
+                userId: app.adminUser.hashid,
+                toolName: 'platform_list_teams',
+                meta: { toolDefinition: { annotations: tool.annotations } }
+            })
+
+            res.ok.should.be.true()
+            createSpy.calledOnce.should.be.true()
+            const nonceArgs = createSpy.firstCall.args[0]
+            nonceArgs.should.have.property('source', 'mcp:expert')
+            nonceArgs.should.have.property('toolName', 'platform_list_teams')
+        })
+
+        it('passes the nonce as x-ff-source-nonce header in the injected request', async function () {
+            const injectSpy = sinon.spy(app, 'inject')
+            const tool = handler.findTool('platform_list_teams')
+
+            const res = await invokeToolCall({
+                userId: app.adminUser.hashid,
+                toolName: 'platform_list_teams',
+                meta: { toolDefinition: { annotations: tool.annotations } }
+            })
+
+            res.ok.should.be.true()
+            injectSpy.calledOnce.should.be.true()
+            const injectOpts = injectSpy.firstCall.args[0]
+            injectOpts.headers.should.have.property('x-ff-source-nonce')
+            injectOpts.headers['x-ff-source-nonce'].should.be.a.String()
+            injectOpts.headers['x-ff-source-nonce'].should.match(/^[a-f0-9]{32}$/)
+        })
+
+        it('mints a fresh nonce per inject call', async function () {
+            const createSpy = sinon.spy(app.nonceStore, 'createSourceNonce')
+            const tool = handler.findTool('platform_list_teams')
+
+            // Call twice
+            await invokeToolCall({
+                userId: app.adminUser.hashid,
+                toolName: 'platform_list_teams',
+                meta: { toolDefinition: { annotations: tool.annotations } }
+            })
+            await invokeToolCall({
+                userId: app.adminUser.hashid,
+                toolName: 'platform_list_teams',
+                meta: { toolDefinition: { annotations: tool.annotations } }
+            })
+
+            createSpy.callCount.should.be.greaterThanOrEqual(2)
+        })
+
+        it('includes authorization header with the platform token', async function () {
+            const injectSpy = sinon.spy(app, 'inject')
+            const tool = handler.findTool('platform_list_teams')
+
+            await invokeToolCall({
+                userId: app.adminUser.hashid,
+                toolName: 'platform_list_teams',
+                meta: { toolDefinition: { annotations: tool.annotations } }
+            })
+
+            injectSpy.calledOnce.should.be.true()
+            const injectOpts = injectSpy.firstCall.args[0]
+            injectOpts.headers.should.have.property('authorization')
+            injectOpts.headers.authorization.should.startWith('Bearer ')
+        })
+    })
+
+    describe('end-to-end audit trail', function () {
+        it('tool call produces audit entry with source mcp:expert and toolName', async function () {
+            const tool = handler.findTool('platform_create_application')
+
+            const res = await invokeToolCall({
+                userId: app.adminUser.hashid,
+                toolName: 'platform_create_application',
+                args: { name: 'audit-trail-test-app', teamId: app.team.hashid },
+                meta: { toolDefinition: { annotations: tool.annotations } }
+            })
+
+            res.ok.should.be.true()
+
+            const entry = await app.db.models.AuditLog.findOne({
+                where: { event: 'application.created' },
+                order: [['createdAt', 'DESC']]
+            })
+            should.exist(entry)
+            entry.source.should.equal('mcp:expert')
+            const body = JSON.parse(entry.body)
+            body.sourceContext.should.have.property('toolName', 'platform_create_application')
+        })
+    })
+})