diff --git a/.changeset/scoped-session-invalidation.md b/.changeset/scoped-session-invalidation.md
new file mode 100644
index 000000000..ab50ccdbb
--- /dev/null
+++ b/.changeset/scoped-session-invalidation.md
@@ -0,0 +1,5 @@
+---
+'@conciv/embed': patch
+---
+
+Scope widget session invalidation to the session list, so adding, closing or creating a pane no longer re-resolves the warm session over the wire.
diff --git a/.fallowrc.json b/.fallowrc.json
index 64a3af315..ccb3c8166 100644
--- a/.fallowrc.json
+++ b/.fallowrc.json
@@ -106,7 +106,6 @@
     "@conciv/extension-whiteboard",
     "@conciv/grab",
     "@conciv/harness",
-    "@conciv/harness-testkit",
     "@conciv/it",
     "@conciv/mascot",
     "@conciv/plugin",
diff --git a/apps/conciv/src/data/app-data.ts b/apps/conciv/src/data/app-data.ts
index 3ee0bbf66..018a45749 100644
--- a/apps/conciv/src/data/app-data.ts
+++ b/apps/conciv/src/data/app-data.ts
@@ -11,6 +11,6 @@ export function makeAppData(rpc: RpcClient, queryClient: QueryClient): AppData {
   const utils = makeQueryUtils(rpc)
   return {
     utils,
-    invalidateSessions: () => void queryClient.invalidateQueries({queryKey: utils.sessions.key()}),
+    invalidateSessions: () => void queryClient.invalidateQueries({queryKey: utils.sessions.list.key()}),
   }
 }
diff --git a/apps/conciv/test/quick-add-pane.browser.test.tsx b/apps/conciv/test/quick-add-pane.browser.test.tsx
index 6d54c3cdc..a0466ae37 100644
--- a/apps/conciv/test/quick-add-pane.browser.test.tsx
+++ b/apps/conciv/test/quick-add-pane.browser.test.tsx
@@ -8,6 +8,7 @@ import {trackedFaults} from './helpers/tracked-faults.js'
 import {expectRetryRecovers} from './helpers/retry-recovery.js'
 
 const RESOLVE_PATH = ['sessions', 'resolve']
+const LIST_PATH = ['sessions', 'list']
 
 const core = {base: ''}
 const harness = createShellHarness(() => core.base)
@@ -63,3 +64,26 @@ test('rapid double-trigger creates exactly one pane', async () => {
   await expect.element(closePane().nth(1), {timeout: 8000}).toBeVisible()
   await expect.element(closePane().nth(2)).not.toBeInTheDocument()
 }, 30_000)
+
+test('adding and closing a pane never re-resolves the warm session', async () => {
+  const rpc = coreRpc(core.base)
+  const sessionId = await createSession(rpc)
+  const mountMark = await coreControl.rpcMark()
+  harness.mountShell(`/quick?panes=${sessionId}&focus=0`)
+  await expect.element(editor(), {timeout: 8000}).toBeVisible()
+  await coreControl.awaitRpcCall(RESOLVE_PATH, mountMark)
+  const resolvesAfterWarmUp = await coreControl.rpcCallCount(RESOLVE_PATH)
+
+  const addMark = await coreControl.rpcMark()
+  await page.getByRole('button', {name: 'Split pane (Mod+D)'}).click()
+  await expect.element(closePane().nth(1), {timeout: 8000}).toBeVisible()
+  expect(await coreControl.awaitRpcCall(LIST_PATH, addMark)).toBe(200)
+
+  const closeMark = await coreControl.rpcMark()
+  await closePane().nth(1).click()
+  await expect.element(closePane().nth(1)).not.toBeInTheDocument()
+  expect(await coreControl.awaitRpcCall(LIST_PATH, closeMark)).toBe(200)
+  await rpc.sessions.list()
+
+  expect((await coreControl.rpcCallCount(RESOLVE_PATH)) - resolvesAfterWarmUp).toBe(1)
+}, 30_000)
diff --git a/packages/harness-testkit/src/run-events.ts b/packages/harness-testkit/src/run-events.ts
index 56df7e3be..b11b66ed0 100644
--- a/packages/harness-testkit/src/run-events.ts
+++ b/packages/harness-testkit/src/run-events.ts
@@ -26,7 +26,7 @@ function parseArgs(raw: string): unknown {
   }
 }
 
-export function renderedMessages(all: StreamChunk[]): unknown[] {
+function renderedMessages(all: StreamChunk[]): unknown[] {
   const processor = new StreamProcessor({})
   for (const chunk of all) processor.processChunk(chunk)
   return processor.getMessages()
@@ -64,7 +64,7 @@ export function collectToolCalls(all: StreamChunk[], name?: string): SeenToolCal
     .map((part) => ({toolCallId: part.id, name: part.name, input: parseArgs(part.arguments)}))
 }
 
-export function snapshotText(all: StreamChunk[]): string {
+function snapshotText(all: StreamChunk[]): string {
   return partsOf(all, 'assistant')
     .flatMap((part) => {
       const parsed = TextPartSchema.safeParse(part)