diff --git a/mobile/src/session/mobile-host-model-catalog-query.test.ts b/mobile/src/session/mobile-host-model-catalog-query.test.ts
new file mode 100644
index 00000000000..2abb4b8847a
--- /dev/null
+++ b/mobile/src/session/mobile-host-model-catalog-query.test.ts
@@ -0,0 +1,78 @@
+import { createElement, useLayoutEffect } from 'react'
+import { act, type ReactTestRenderer } from 'react-test-renderer'
+import { describe, expect, it } from 'vitest'
+import type { AgentSessionModelCatalogResult } from '../../../src/shared/agent-session/agent-session-wire'
+import { AGENT_SESSION_MODEL_CATALOG_SAVED_ONLY_RUNTIME_CAPABILITY } from '../../../src/shared/agent-session/structured-agent-session-surface-capabilities'
+import { createWithQueryClient } from '../test-support/query-client-test-renderer'
+import type { RpcClient } from '../transport/rpc-client'
+import { recordRuntimeStatusProbe } from '../transport/runtime-status-probe'
+import { useHostModelCatalogCache } from './mobile-host-model-catalog-query'
+import type { HostModelCatalogCache } from './use-mobile-host-model-catalog-upgrade'
+
+function listed(id: string): AgentSessionModelCatalogResult {
+  return {
+    origin: 'probe',
+    models: [{ id, label: id, isDefault: true, efforts: [] }],
+    fetchedAt: 1,
+    listingNamesConfiguredModel: false
+  }
+}
+
+function heldPreloadClient() {
+  let answer: (catalog: AgentSessionModelCatalogResult) => void = () => {}
+  const client: RpcClient = {
+    sendRequest: () =>
+      new Promise((resolve) => {
+        answer = (catalog) =>
+          resolve({ id: 'r', ok: true, result: catalog, _meta: { runtimeId: 'runtime-1' } })
+      }),
+    subscribe: () => () => {},
+    updateTerminalSubscriptionViewport: () => {},
+    getState: () => 'connected',
+    getReconnectAttempt: () => 0,
+    getLastConnectedAt: () => 1,
+    onStateChange: () => () => {},
+    notifyForeground: () => {},
+    close: () => {}
+  }
+  recordRuntimeStatusProbe(client, {
+    capabilities: [AGENT_SESSION_MODEL_CATALOG_SAVED_ONLY_RUNTIME_CAPABILITY]
+  })
+  return { client, answer: (catalog: AgentSessionModelCatalogResult) => answer(catalog) }
+}
+
+async function mountCache(client: RpcClient) {
+  const mounted: { cache: HostModelCatalogCache | null } = { cache: null }
+  function Probe(): null {
+    const current = useHostModelCatalogCache({
+      hostId: 'host-1',
+      client,
+      agent: 'claude',
+      enabled: true
+    })
+    useLayoutEffect(() => {
+      mounted.cache = current
+    })
+    return null
+  }
+  let renderer: ReactTestRenderer | null = null
+  await act(async () => {
+    renderer = createWithQueryClient(createElement(Probe))
+  })
+  return { mounted, unmount: () => act(async () => renderer?.unmount()) }
+}
+
+describe('useHostModelCatalogCache', () => {
+  it("keeps a new chat's answer that lands while an older preload is out", async () => {
+    const host = heldPreloadClient()
+    const { mounted, unmount } = await mountCache(host.client)
+
+    await act(async () => mounted.cache?.record('wt-1', listed('opus')))
+    await act(async () => host.answer(listed('sonnet')))
+
+    expect(mounted.cache?.seed({ newLaunch: true, worktree: 'wt-1', seedsModel: false })).toEqual(
+      listed('opus')
+    )
+    await unmount()
+  })
+})
diff --git a/mobile/src/session/mobile-host-model-catalog-query.ts b/mobile/src/session/mobile-host-model-catalog-query.ts
index 93b56929476..a4bfe515754 100644
--- a/mobile/src/session/mobile-host-model-catalog-query.ts
+++ b/mobile/src/session/mobile-host-model-catalog-query.ts
@@ -72,11 +72,22 @@ export function useHostModelCatalogCache(args: {
           launch
         ),
       // A new chat's answer is the account's a new chat pins, so the next chat starts from it.
-      record: (worktree, catalog) =>
-        queryClient.setQueryData<HostModelCatalogSnapshot | null>(
-          queryKey,
-          (snapshot) => withHostModelCatalogAnswer(snapshot ?? undefined, worktree, catalog) ?? null
-        )
+      record: (worktree, catalog) => {
+        const held =
+          queryClient.getQueryData<HostModelCatalogSnapshot | null>(queryKey) ?? undefined
+        const next = withHostModelCatalogAnswer(held, worktree, catalog)
+        if (next === held) {
+          return
+        }
+        queryClient.setQueryData<HostModelCatalogSnapshot | null>(queryKey, next ?? null)
+        // A preload sent before this list is older; cancelling it keeps the list just set.
+        if (
+          next?.byWorktree.has(worktree) &&
+          queryClient.isFetching({ queryKey, exact: true }) > 0
+        ) {
+          void queryClient.cancelQueries({ queryKey, exact: true }, { silent: true })
+        }
+      }
     }
   }, [agent, exec, hostId, queryClient])
 }
diff --git a/mobile/src/session/use-mobile-host-model-catalog-upgrade.ts b/mobile/src/session/use-mobile-host-model-catalog-upgrade.ts
index 3fd44f74c26..72a3a902735 100644
--- a/mobile/src/session/use-mobile-host-model-catalog-upgrade.ts
+++ b/mobile/src/session/use-mobile-host-model-catalog-upgrade.ts
@@ -34,6 +34,8 @@ export function useMobileHostModelCatalogUpgrade(args: {
   newLaunch: boolean
   /** Where a new chat runs: the host names no default its config could replace. */
   worktree?: string
+  /** The chat has a turn or a send, so its answers are its own account's, which a new chat may no longer pin. */
+  hasTurn?: boolean
   fence: number | null
   optionCatalog: AgentSessionOptionCatalog | null
   receiveCatalog: (
@@ -62,9 +64,12 @@ export function useMobileHostModelCatalogUpgrade(args: {
     worktree
   } = args
   const receiver = useRef(args.receiveCatalog)
+  const recordsNewChat = useRef(newLaunch && args.hasTurn !== true)
+  const recordingWait = useRef<string | null>(null)
   useEffect(() => {
     receiver.current = args.receiveCatalog
-  }, [args.receiveCatalog])
+    recordsNewChat.current = newLaunch && args.hasTurn !== true
+  }, [args.receiveCatalog, newLaunch, args.hasTurn])
   const [rereads, setRereads] = useState(0)
   const selectedModel = usesModelSpecificAcpEfforts(agent ?? '') ? args.selectedModel : undefined
   const recheck = useCallback(() => setRereads((count) => count + 1), [])
@@ -73,6 +78,12 @@ export function useMobileHostModelCatalogUpgrade(args: {
       return
     }
     let stale = false
+    const key = `${agent}\u0000${sessionId}`
+    // A read sent before the chat's first turn or send answers for the account a new chat pins,
+    // and so does the listing it waits on, whichever later run picks that up.
+    const records =
+      recordsNewChat.current ||
+      (recordingWait.current === key && isHostModelListingWaitInFlight(key, client))
     const params = {
       agent,
       sessionId,
@@ -98,7 +109,7 @@ export function useMobileHostModelCatalogUpgrade(args: {
         return
       }
       // A new chat's answer is the account's a new chat pins, so the next chat starts from it.
-      if (newLaunch) {
+      if (records) {
         modelCatalogCache?.record(worktree ?? '', catalog)
       }
       receiver.current(catalog, settled ? 'settled' : event)
@@ -109,9 +120,9 @@ export function useMobileHostModelCatalogUpgrade(args: {
         receiver.current(null, 'demand')
       }
     }
-    const key = `${agent}\u0000${sessionId}`
     let leave: (() => void) | undefined
     const wait = () => {
+      recordingWait.current = records ? key : null
       leave = joinHostModelListingWait(
         key,
         () => read(true),
diff --git a/mobile/src/session/use-mobile-structured-agent-options.ts b/mobile/src/session/use-mobile-structured-agent-options.ts
index 5a4af847ce8..4e5e5403306 100644
--- a/mobile/src/session/use-mobile-structured-agent-options.ts
+++ b/mobile/src/session/use-mobile-structured-agent-options.ts
@@ -187,6 +187,7 @@ export function useMobileStructuredAgentOptions(args: {
     fence,
     newLaunch: createdHere !== undefined,
     ...(createdHere ? { worktree: createdHere.worktree } : {}),
+    hasTurn: args.hasTurn,
     optionCatalog,
     activeOptionRecordRef,
     updateOptionState,
diff --git a/mobile/src/session/use-mobile-structured-option-state.ts b/mobile/src/session/use-mobile-structured-option-state.ts
index d25cec5f411..db8bac20822 100644
--- a/mobile/src/session/use-mobile-structured-option-state.ts
+++ b/mobile/src/session/use-mobile-structured-option-state.ts
@@ -11,10 +11,7 @@ import { BoundedMap } from '../../../src/shared/bounded-map'
 import type { RpcClient } from '../transport/rpc-client'
 import type { AgentSessionOptionCatalog } from '../../../src/shared/agent-session/options/agent-session-option-catalog-types'
 import { usesInstalledAgentModelCatalog } from '../../../src/shared/agent-session/options/agent-model-catalog-ownership'
-import {
-  applyStructuredAgentSessionModelCatalog,
-  createStructuredAgentSessionOptionState
-} from '../../../src/shared/agent-session/options/structured-agent-session-options'
+import { structuredAgentSessionFirstFrameOptionState } from '../../../src/shared/agent-session/options/structured-agent-session-first-frame'
 import type { HostModelCatalogCache } from './use-mobile-host-model-catalog-upgrade'
 import { structuredAgentSessionReportsAtFence } from '../../../src/shared/agent-session/options/structured-agent-session-runtime-reports'
 
@@ -70,18 +67,13 @@ export function useMobileStructuredOptionState(args: {
   const providerStarting = summary?.hostExecutionPhase === 'starting'
   const coherentCatalog = usesInstalledAgentModelCatalog(agent ?? '', hostCoherentCatalog)
   // The host's last list for this agent when this world holds one, else the quiet placeholder until the host answers.
-  const firstFrame = () => {
-    const seeded = createStructuredAgentSessionOptionState(agent ?? 'codex', optionCatalog)
-    const listed =
-      optionCatalog &&
-      modelCatalogCache?.seed({ newLaunch, seedsModel: false, ...(worktree ? { worktree } : {}) })
-    return listed && optionCatalog
-      ? applyStructuredAgentSessionModelCatalog(seeded, optionCatalog, listed, {
-          newLaunch,
-          coherentCatalog
-        })
-      : seeded
-  }
+  const firstFrame = () =>
+    structuredAgentSessionFirstFrameOptionState(
+      agent ?? 'codex',
+      optionCatalog,
+      modelCatalogCache?.seed({ newLaunch, seedsModel: false, ...(worktree ? { worktree } : {}) }),
+      { newLaunch, coherentCatalog }
+    )
   // One view serves every chat tab, so each chat keeps its own reader and its last answer on return.
   const [readers] = useState(
     () =>
diff --git a/src/renderer/src/components/native-chat/session/options/catalog/use-host-model-catalog-upgrade.ts b/src/renderer/src/components/native-chat/session/options/catalog/use-host-model-catalog-upgrade.ts
index 6f6c6645d11..15d80316c1d 100644
--- a/src/renderer/src/components/native-chat/session/options/catalog/use-host-model-catalog-upgrade.ts
+++ b/src/renderer/src/components/native-chat/session/options/catalog/use-host-model-catalog-upgrade.ts
@@ -38,6 +38,8 @@ export function useHostModelCatalogUpgrade(args: {
   newLaunch: boolean
   /** Where the launch runs: the host names no default its config could replace. */
   worktree?: string
+  /** The chat has a turn or a send, so its answers are its own account's, which a new chat may no longer pin. */
+  hasTurn?: boolean
   fence: number | null
   /** The chat's running turn: one running proves its start, which the host re-checks against. */
   turnId?: string | null
@@ -70,9 +72,12 @@ export function useHostModelCatalogUpgrade(args: {
     worktree
   } = args
   const receiver = useRef(args.receiveCatalog)
+  const recordsNewChat = useRef(newLaunch && args.hasTurn !== true)
+  const recordingWait = useRef<string | null>(null)
   useEffect(() => {
     receiver.current = args.receiveCatalog
-  }, [args.receiveCatalog])
+    recordsNewChat.current = newLaunch && args.hasTurn !== true
+  }, [args.receiveCatalog, newLaunch, args.hasTurn])
   const waitKey = `${structuredAgentSessionHostKey(target)}\u0000${agent}\u0000${sessionId}`
   const [verdict, setVerdict] = useState<{
     key: string
@@ -104,6 +109,11 @@ export function useHostModelCatalogUpgrade(args: {
       return
     }
     let stale = false
+    // A read sent before the chat's first turn or send answers for the account a new chat pins,
+    // and so does the listing it waits on, whichever later run picks that up.
+    const records =
+      recordsNewChat.current ||
+      (recordingWait.current === waitKey && isHostModelListingWaitInFlight(waitKey))
     const params = {
       agent,
       sessionId,
@@ -134,13 +144,14 @@ export function useHostModelCatalogUpgrade(args: {
           : { key: waitKey, unavailable: next }
       })
       // A new chat's answer is the account's a new chat pins, so the next chat starts from it.
-      if (catalog && newLaunch) {
+      if (catalog && records) {
         recordHostModelCatalogSnapshot(target, agent, worktree ?? '', catalog)
       }
       receiver.current(catalog, settled ? 'settled' : event)
     }
     let leave: (() => void) | null = null
     const waitForListing = (): void => {
+      recordingWait.current = records ? waitKey : null
       leave = joinHostModelListingWait(
         waitKey,
         () => read(true),
diff --git a/src/renderer/src/components/native-chat/session/options/structured/structured-agent-session-option-first-frame.ts b/src/renderer/src/components/native-chat/session/options/structured/structured-agent-session-option-first-frame.ts
index 73864558918..4f3d67bd44a 100644
--- a/src/renderer/src/components/native-chat/session/options/structured/structured-agent-session-option-first-frame.ts
+++ b/src/renderer/src/components/native-chat/session/options/structured/structured-agent-session-option-first-frame.ts
@@ -1,22 +1,20 @@
 import type { AgentType } from '../../../../../../../shared/agent-status/contracts/agent-status-types'
 import type { RuntimeClientTarget } from '../../../../../../../shared/runtime-client-target'
 import { structuredAgentSessionSeedCatalog } from '../../../../../../../shared/agent-session/options/structured-agent-session-seed-catalog'
-import {
-  applyStructuredAgentSessionModelCatalog,
-  createStructuredAgentSessionOptionState,
-  type StructuredAgentSessionOptionState
-} from '../../../../../../../shared/agent-session/options/structured-agent-session-options'
+import type { StructuredAgentSessionOptionState } from '../../../../../../../shared/agent-session/options/structured-agent-session-options'
+import { structuredAgentSessionFirstFrameOptionState } from '../../../../../../../shared/agent-session/options/structured-agent-session-first-frame'
 import { readHostModelCatalogSnapshot } from '@/runtime/host-model-catalog-snapshots'
 
-/** The first frame: the host's saved list when the renderer already holds it, else the seed,
- *  which shows the quiet placeholder until the host answers. */
+/** The first frame from the host's saved list when the renderer already holds it. */
 export function firstFrameOptionState(
   agent: AgentType,
   target: RuntimeClientTarget,
   launch: { newLaunch: boolean; worktree?: string; seedsModel: boolean }
 ): StructuredAgentSessionOptionState {
-  const seed = structuredAgentSessionSeedCatalog(agent)
-  const seeded = createStructuredAgentSessionOptionState(agent, seed)
-  const snapshot = readHostModelCatalogSnapshot(target, agent, launch)
-  return snapshot ? applyStructuredAgentSessionModelCatalog(seeded, seed, snapshot, launch) : seeded
+  return structuredAgentSessionFirstFrameOptionState(
+    agent,
+    structuredAgentSessionSeedCatalog(agent),
+    readHostModelCatalogSnapshot(target, agent, launch),
+    launch
+  )
 }
diff --git a/src/renderer/src/components/native-chat/session/options/structured/use-structured-agent-session-options.ts b/src/renderer/src/components/native-chat/session/options/structured/use-structured-agent-session-options.ts
index 175bd9a2947..0a192e5b374 100644
--- a/src/renderer/src/components/native-chat/session/options/structured/use-structured-agent-session-options.ts
+++ b/src/renderer/src/components/native-chat/session/options/structured/use-structured-agent-session-options.ts
@@ -95,6 +95,7 @@ export function useStructuredAgentSessionOptions(args: StructuredAgentSessionOpt
     // A resumed conversation may keep its own model, so only a new one runs the listed default.
     newLaunch,
     ...(launch?.worktree ? { worktree: launch.worktree } : {}),
+    hasTurn: args.hasTurn,
     fence,
     turnId,
     reportedUnpickedModel:
diff --git a/src/renderer/src/runtime/host-model-catalog-snapshots.test.ts b/src/renderer/src/runtime/host-model-catalog-snapshots.test.ts
index 0e5a303cc5d..07a7ee10923 100644
--- a/src/renderer/src/runtime/host-model-catalog-snapshots.test.ts
+++ b/src/renderer/src/runtime/host-model-catalog-snapshots.test.ts
@@ -31,6 +31,7 @@ import { getDefaultSettings } from '../../../shared/constants'
 import type { PublicKnownRuntimeEnvironment } from '../../../shared/remote-runtime/host-catalog/runtime-environments'
 import { useAppStore } from '@/store'
 import {
+  preloadHostModelCatalogSnapshots,
   readHostModelCatalogSnapshot,
   recordHostModelCatalogSnapshot,
   resetHostModelCatalogSnapshotsForTests
@@ -83,6 +84,31 @@ describe('host model catalog snapshots', () => {
     recordHostModelCatalogSnapshot(LOCAL, 'grok', 'wt-1', { origin: 'unknown' })
     expect(readHostModelCatalogSnapshot(LOCAL, 'grok', NEW_CHAT)).toBe(worldwide)
   })
+
+  it('keeps a held list through an answer whose listing is still running', () => {
+    const held = list(true)
+    recordHostModelCatalogSnapshot(LOCAL, 'claude', 'wt-1', held)
+    recordHostModelCatalogSnapshot(LOCAL, 'claude', 'wt-1', {
+      origin: 'unknown',
+      listingInProgress: true
+    })
+    expect(readHostModelCatalogSnapshot(LOCAL, 'claude', NEW_CHAT)).toBe(held)
+    const other = { ...NEW_CHAT, worktree: 'wt-2' }
+    const filling = { ...list(true), listingInProgress: true as const }
+    recordHostModelCatalogSnapshot(LOCAL, 'claude', 'wt-2', filling)
+    expect(readHostModelCatalogSnapshot(LOCAL, 'claude', other)).toBe(filling)
+  })
+
+  it("keeps a chat's answer that lands while an older preload is out", async () => {
+    let answer: (catalog: AgentSessionModelCatalogResult) => void = () => {}
+    mocks.call.mockImplementation(() => new Promise((resolve) => (answer = resolve)))
+    const preload = preloadHostModelCatalogSnapshots(LOCAL, ['claude'], { savedOnly: true })
+    const chat = list(true)
+    recordHostModelCatalogSnapshot(LOCAL, 'claude', 'wt-1', chat)
+    answer(list(false))
+    await preload
+    expect(readHostModelCatalogSnapshot(LOCAL, 'claude', NEW_CHAT)).toBe(chat)
+  })
 })
 
 const SAVED_ONLY = 'agent-session.model-catalog.saved-only.v1'
diff --git a/src/renderer/src/runtime/host-model-catalog-snapshots.ts b/src/renderer/src/runtime/host-model-catalog-snapshots.ts
index c5fc9357e58..a53ea6306dc 100644
--- a/src/renderer/src/runtime/host-model-catalog-snapshots.ts
+++ b/src/renderer/src/runtime/host-model-catalog-snapshots.ts
@@ -13,6 +13,8 @@ import { structuredAgentSessionHostKey } from './structured-agent-session-host-c
 const snapshots = new Map<string, HostModelCatalogSnapshot>()
 // Bumped when a host's answers are dropped, so a preload sent before then records nothing.
 const generations = new Map<string, number>()
+// Bumped per host and agent by each chat's answer, so an older preload never replaces it.
+const chatAnswers = new Map<string, number>()
 
 function snapshotKey(hostKey: string, agent: string): string {
   return `${hostKey}\u0000${agent}`
@@ -39,6 +41,9 @@ export function recordHostModelCatalogSnapshot(
 ): void {
   const key = snapshotKey(structuredAgentSessionHostKey(target), agent)
   const next = withHostModelCatalogAnswer(snapshots.get(key), worktree, catalog)
+  if (worktree !== null && next !== snapshots.get(key) && next?.byWorktree.has(worktree)) {
+    chatAnswers.set(key, (chatAnswers.get(key) ?? 0) + 1)
+  }
   if (next) {
     snapshots.set(key, next)
   } else {
@@ -78,23 +83,29 @@ export async function preloadHostModelCatalogSnapshots(
   const hostKey = structuredAgentSessionHostKey(target)
   const generation = generations.get(hostKey) ?? 0
   await Promise.all(
-    agents.map((agent) =>
-      callStructuredAgentSession<AgentSessionModelCatalogResult>(
+    agents.map((agent) => {
+      const key = snapshotKey(hostKey, agent)
+      const answersAtSend = chatAnswers.get(key) ?? 0
+      return callStructuredAgentSession<AgentSessionModelCatalogResult>(
         target,
         'agentSession.modelCatalog',
         { agent, ...options }
       )
         .then((catalog) => {
-          if ((generations.get(hostKey) ?? 0) === generation) {
+          if (
+            (generations.get(hostKey) ?? 0) === generation &&
+            (chatAnswers.get(key) ?? 0) === answersAtSend
+          ) {
             recordHostModelCatalogSnapshot(target, agent, null, catalog)
           }
         })
         .catch(() => undefined)
-    )
+    })
   )
 }
 
 export function resetHostModelCatalogSnapshotsForTests(): void {
   snapshots.clear()
   generations.clear()
+  chatAnswers.clear()
 }
diff --git a/src/shared/agent-session/options/host-model-catalog-snapshot-rules.ts b/src/shared/agent-session/options/host-model-catalog-snapshot-rules.ts
index 6298b02a7c8..00557f102bb 100644
--- a/src/shared/agent-session/options/host-model-catalog-snapshot-rules.ts
+++ b/src/shared/agent-session/options/host-model-catalog-snapshot-rules.ts
@@ -53,16 +53,30 @@ export function selectHostModelCatalogSnapshot(
 }
 
 /** The snapshot after a host answer for `worktree` (null for a session-less read); undefined means keep none.
- *  An unknown or empty answer proves absence and retires what it answered for. */
+ *  An unknown or empty answer proves absence and retires what it answered for. One whose listing is
+ *  still running proves nothing yet: it never replaces or retires a held list, but may fill an empty scope. */
 export function withHostModelCatalogAnswer(
   snapshot: HostModelCatalogSnapshot | undefined,
   worktree: string | null,
   catalog: AgentSessionModelCatalogResult
 ): HostModelCatalogSnapshot | undefined {
-  if (catalog.origin === 'unknown' || catalog.models.length === 0) {
+  const listed = catalog.origin !== 'unknown' && catalog.models.length > 0
+  if (catalog.listingInProgress) {
+    const held =
+      worktree === null
+        ? !!snapshot && (snapshot.account !== null || snapshot.byWorktree.size > 0)
+        : snapshot?.byWorktree.has(worktree) === true
+    if (held || !listed) {
+      return snapshot
+    }
+  }
+  if (!listed) {
     if (worktree === null || !snapshot) {
       return undefined
     }
+    if (!snapshot.byWorktree.has(worktree)) {
+      return snapshot
+    }
     const retired = snapshot.byWorktree.get(worktree)
     const byWorktree = new Map(snapshot.byWorktree)
     byWorktree.delete(worktree)
diff --git a/src/shared/agent-session/options/structured-agent-session-first-frame.ts b/src/shared/agent-session/options/structured-agent-session-first-frame.ts
new file mode 100644
index 00000000000..be9534cf7ce
--- /dev/null
+++ b/src/shared/agent-session/options/structured-agent-session-first-frame.ts
@@ -0,0 +1,21 @@
+import type { AgentSessionModelCatalogResult } from '../agent-session-wire'
+import type { AgentSessionOptionCatalog } from './agent-session-option-catalog-types'
+import {
+  applyStructuredAgentSessionModelCatalog,
+  createStructuredAgentSessionOptionState,
+  type StructuredAgentSessionOptionState
+} from './structured-agent-session-options'
+
+/** A chat's first frame: the host's held list when the client has one, else the seed, which shows
+ *  the quiet placeholder until the host answers. */
+export function structuredAgentSessionFirstFrameOptionState(
+  agent: string,
+  seed: AgentSessionOptionCatalog | null,
+  held: AgentSessionModelCatalogResult | undefined,
+  options: { newLaunch: boolean; coherentCatalog?: boolean }
+): StructuredAgentSessionOptionState {
+  const seeded = createStructuredAgentSessionOptionState(agent, seed)
+  return held && seed
+    ? applyStructuredAgentSessionModelCatalog(seeded, seed, held, options)
+    : seeded
+}