diff --git a/src/renderer/src/lib/launch-agent-in-new-tab-web-runtime.test.ts b/src/renderer/src/lib/launch-agent-in-new-tab-web-runtime.test.ts
index d3638c3b71a..171f5988747 100644
--- a/src/renderer/src/lib/launch-agent-in-new-tab-web-runtime.test.ts
+++ b/src/renderer/src/lib/launch-agent-in-new-tab-web-runtime.test.ts
@@ -93,8 +93,7 @@ describe('launchAgentInNewTab paired web runtime', () => {
       activate: true,
       agentSessionKind: 'fresh',
       agent: 'claude',
-      // Why: an unconfigured client still resolves the default explicitly, so
-      // the host applies this client's launch defaults rather than its own.
+      // Why: the client resolves its default explicitly so the host cannot apply its own.
       agentArgs: '--dangerously-skip-permissions',
       viewMode: 'terminal'
     })
diff --git a/src/renderer/src/lib/launch-agent-in-new-tab.ts b/src/renderer/src/lib/launch-agent-in-new-tab.ts
index 71e591155fe..0c45a11c544 100644
--- a/src/renderer/src/lib/launch-agent-in-new-tab.ts
+++ b/src/renderer/src/lib/launch-agent-in-new-tab.ts
@@ -157,11 +157,8 @@ export function launchAgentInNewTab(args: LaunchAgentInNewTabArgs): LaunchAgentI
       promptDelivery,
       pastePromptAfterReady: pasteDraftAfterLaunch,
       submitPastedPrompt,
-      // Why: the raw param is undefined on ordinary UI launches, and omitting it
-      // lets a headless host apply its own defaults — so a client configured for
-      // Manual gets the host's YOLO default (#15373). Send the client-resolved
-      // value, empty string included: the host treats present-but-empty as an
-      // explicit no-args override.
+      // Why: the raw param is undefined on ordinary UI launches, so omission let a headless host apply its
+      // own YOLO default (#15373). Send the resolved value — present-but-empty is an explicit no-args override.
       agentArgs: effectiveAgentArgs,
       // Why: omission means terminal locally, but would let a paired host apply
       // its own default; send the client's resolved terminal choice explicitly.
@@ -195,6 +192,7 @@ export function launchAgentInNewTab(args: LaunchAgentInNewTabArgs): LaunchAgentI
     ...(startupPlan.env ? { env: startupPlan.env } : {}),
     launchConfig: startupPlan.launchConfig,
     launchAgent: agent,
+    // Why: the local launch command already bakes in the resolved args, so this override only records explicit caller intent.
     ...(agentArgs !== undefined ? { agentArgsOverride: agentArgs } : {}),
     ...(startupPlan.sessionOptions ? { sessionOptions: startupPlan.sessionOptions } : {}),
     ...(startupPlan.startupCommandDelivery
diff --git a/src/renderer/src/runtime/web-runtime-session-terminal-host-authority.test.ts b/src/renderer/src/runtime/web-runtime-session-terminal-host-authority.test.ts
index 13ec579a2f7..843cfa8e607 100644
--- a/src/renderer/src/runtime/web-runtime-session-terminal-host-authority.test.ts
+++ b/src/renderer/src/runtime/web-runtime-session-terminal-host-authority.test.ts
@@ -325,6 +325,65 @@ describe('createWebRuntimeSessionTerminal', () => {
     )
   })
 
+  it('keeps an explicit empty agentArgs in the structured create payload', async () => {
+    // Why (#15373): Manual is stored as an empty string; dropping it here would let the host re-resolve YOLO.
+    const runtimeCall = vi.fn(async (request: { method: string }) => {
+      if (request.method === 'status.get') {
+        return {
+          id: 'status',
+          ok: true,
+          result: {
+            runtimeId: 'runtime-1',
+            graphStatus: 'ready',
+            runtimeProtocolVersion: 3,
+            minCompatibleRuntimeClientVersion: 2,
+            capabilities: ['agent-session.host-authority.v1']
+          }
+        }
+      }
+      if (request.method === 'terminal.createAgentSession') {
+        return {
+          id: 'agent-session',
+          ok: true,
+          result: {
+            terminal: {
+              handle: 'term-manual',
+              worktreeId: WORKTREE_ID,
+              tabId: 'host-tab-manual',
+              paneKey: `host-tab-manual:${FOCUS_LEAF_ID}`
+            },
+            disposition: 'created'
+          }
+        }
+      }
+      return { id: 'list', ok: true, result: makeSnapshot() }
+    })
+    vi.stubGlobal('window', {
+      api: { runtimeEnvironments: { call: runtimeCall } }
+    })
+
+    await expect(
+      createWebRuntimeSessionTerminal({
+        worktreeId: WORKTREE_ID,
+        agent: 'claude',
+        agentSessionKind: 'fresh',
+        agentArgs: '',
+        activate: true
+      })
+    ).resolves.toEqual({ status: 'created' })
+
+    const createRequest = runtimeCall.mock.calls.find(
+      ([request]) => request.method === 'terminal.createAgentSession'
+    )?.[0] as { params: Record<string, unknown> } | undefined
+    expect(createRequest?.params).toEqual({
+      clientOperationId: expect.stringMatching(/^\d{13}-[0-9a-f]{32}$/),
+      worktree: `id:${WORKTREE_ID}`,
+      agent: 'claude',
+      agentArgs: '',
+      presentation: 'background'
+    })
+  })
+
   it.each(['session.tabs.move', 'session.tabs.list'] as const)(
     'treats %s failure after host creation as accepted so callers do not duplicate the agent',
     async (failedMethod) => {