Merge pull request #2302 from RaviTharuma/fix/runtime-fallback-cooldown-session-status

Fix cooldown fallback switching across runtime/model fallback hooks
2026-03-09 13:38:46 +09:00
parent 9e07f1d32b 7d1607dc16
commit 39cbe11432
29 changed files with 1416 additions and 77 deletions
--- a/src/hooks/model-fallback/hook.test.ts
+++ b/src/hooks/model-fallback/hook.test.ts
@@ -140,6 +140,121 @@ describe("model fallback hook", () => {
    expect(secondOutput.message["variant"]).toBeUndefined()
  })

+  test("does not re-arm fallback when one is already pending", () => {
+    //#given
+    const sessionID = "ses_model_fallback_pending_guard"
+    clearPendingModelFallback(sessionID)
+
+    //#when
+    const firstSet = setPendingModelFallback(
+      sessionID,
+      "Sisyphus (Ultraworker)",
+      "anthropic",
+      "claude-opus-4-6-thinking",
+    )
+    const secondSet = setPendingModelFallback(
+      sessionID,
+      "Sisyphus (Ultraworker)",
+      "anthropic",
+      "claude-opus-4-6-thinking",
+    )
+
+    //#then
+    expect(firstSet).toBe(true)
+    expect(secondSet).toBe(false)
+    clearPendingModelFallback(sessionID)
+  })
+
+  test("skips no-op fallback entries that resolve to same provider/model", async () => {
+    //#given
+    const sessionID = "ses_model_fallback_noop_skip"
+    clearPendingModelFallback(sessionID)
+
+    const hook = createModelFallbackHook() as unknown as {
+      "chat.message"?: (
+        input: { sessionID: string },
+        output: { message: Record<string, unknown>; parts: Array<{ type: string; text?: string }> },
+      ) => Promise<void>
+    }
+
+    setSessionFallbackChain(sessionID, [
+      { providers: ["anthropic"], model: "claude-opus-4-6" },
+      { providers: ["opencode"], model: "kimi-k2.5-free" },
+    ])
+
+    expect(
+      setPendingModelFallback(
+        sessionID,
+        "Sisyphus (Ultraworker)",
+        "anthropic",
+        "claude-opus-4-6",
+      ),
+    ).toBe(true)
+
+    const output = {
+      message: {
+        model: { providerID: "anthropic", modelID: "claude-opus-4-6" },
+      },
+      parts: [{ type: "text", text: "continue" }],
+    }
+
+    //#when
+    await hook["chat.message"]?.({ sessionID }, output)
+
+    //#then
+    expect(output.message["model"]).toEqual({
+      providerID: "opencode",
+      modelID: "kimi-k2.5-free",
+    })
+    clearPendingModelFallback(sessionID)
+  })
+
+  test("skips no-op fallback entries even when variant differs", async () => {
+    //#given
+    const sessionID = "ses_model_fallback_noop_variant_skip"
+    clearPendingModelFallback(sessionID)
+
+    const hook = createModelFallbackHook() as unknown as {
+      "chat.message"?: (
+        input: { sessionID: string },
+        output: { message: Record<string, unknown>; parts: Array<{ type: string; text?: string }> },
+      ) => Promise<void>
+    }
+
+    setSessionFallbackChain(sessionID, [
+      { providers: ["quotio"], model: "claude-opus-4-6", variant: "max" },
+      { providers: ["quotio"], model: "gpt-5.2" },
+    ])
+
+    expect(
+      setPendingModelFallback(
+        sessionID,
+        "Sisyphus (Ultraworker)",
+        "quotio",
+        "claude-opus-4-6",
+      ),
+    ).toBe(true)
+
+    const output = {
+      message: {
+        model: { providerID: "quotio", modelID: "claude-opus-4-6" },
+        variant: "max",
+      },
+      parts: [{ type: "text", text: "continue" }],
+    }
+
+    //#when
+    await hook["chat.message"]?.({ sessionID }, output)
+
+    //#then
+    expect(output.message["model"]).toEqual({
+      providerID: "quotio",
+      modelID: "gpt-5.2",
+    })
+    expect(output.message["variant"]).toBeUndefined()
+    clearPendingModelFallback(sessionID)
+  })
+
  test("shows toast when fallback is applied", async () => {
    //#given
    const toastCalls: Array<{ title: string; message: string }> = []
@@ -199,7 +314,7 @@ describe("model fallback hook", () => {
      sessionID,
      "Atlas (Plan Executor)",
      "github-copilot",
-      "claude-sonnet-4-6",
+      "claude-sonnet-4-5",
    )
    expect(set).toBe(true)

--- a/src/hooks/model-fallback/hook.ts
+++ b/src/hooks/model-fallback/hook.ts
@@ -39,6 +39,12 @@ const pendingModelFallbacks = new Map<string, ModelFallbackState>()
 const lastToastKey = new Map<string, string>()
 const sessionFallbackChains = new Map<string, FallbackEntry[]>()

+function canonicalizeModelID(modelID: string): string {
+  return modelID
+    .toLowerCase()
+    .replace(/\./g, "-")
+}
+
 export function setSessionFallbackChain(sessionID: string, fallbackChain: FallbackEntry[] | undefined): void {
  if (!sessionID) return
  if (!fallbackChain || fallbackChain.length === 0) {
@@ -77,6 +83,11 @@ export function setPendingModelFallback(
  const existing = pendingModelFallbacks.get(sessionID)

  if (existing) {
+    if (existing.pending) {
+      log("[model-fallback] Pending fallback already armed for session: " + sessionID)
+      return false
+    }
+
    // Preserve progression across repeated session.error retries in same session.
    // We only mark the next turn as pending fallback application.
    existing.providerID = currentProviderID
@@ -140,13 +151,24 @@ export function getNextFallback(
    }

    const providerID = selectFallbackProvider(fallback.providers, state.providerID)
+    const modelID = transformModelForProvider(providerID, fallback.model)
+
+    const isNoOpFallback =
+      providerID.toLowerCase() === state.providerID.toLowerCase() &&
+      canonicalizeModelID(modelID) === canonicalizeModelID(state.modelID)
+
+    if (isNoOpFallback) {
+      log("[model-fallback] Skipping no-op fallback for session: " + sessionID + ", attempt: " + attemptCount + ", model: " + fallback.model)
+      continue
+    }
+
    state.pending = false

    log("[model-fallback] Using fallback for session: " + sessionID + ", attempt: " + attemptCount + ", model: " + fallback.model)

    return {
      providerID,
-      modelID: transformModelForProvider(providerID, fallback.model),
+      modelID,
      variant: fallback.variant,
    }
  }
--- a/src/hooks/runtime-fallback/constants.ts
+++ b/src/hooks/runtime-fallback/constants.ts
@@ -26,6 +26,10 @@ export const RETRYABLE_ERROR_PATTERNS = [
  /rate.?limit/i,
  /too.?many.?requests/i,
  /quota.?exceeded/i,
+  /quota\s+will\s+reset\s+after/i,
+  /all\s+credentials\s+for\s+model/i,
+  /cool(?:ing)?\s+down/i,
+  /exhausted\s+your\s+capacity/i,
  /usage\s+limit\s+has\s+been\s+reached/i,
  /service.?unavailable/i,
  /overloaded/i,
--- a/src/hooks/runtime-fallback/error-classifier.test.ts
+++ b/src/hooks/runtime-fallback/error-classifier.test.ts
@@ -0,0 +1,60 @@
+import { describe, expect, test } from "bun:test"
+
+import { extractAutoRetrySignal, isRetryableError } from "./error-classifier"
+
+describe("runtime-fallback error classifier", () => {
+  test("detects cooling-down auto-retry status signals", () => {
+    //#given
+    const info = {
+      status:
+        "All credentials for model claude-opus-4-6-thinking are cooling down [retrying in ~5 days attempt #1]",
+    }
+
+    //#when
+    const signal = extractAutoRetrySignal(info)
+
+    //#then
+    expect(signal).toBeDefined()
+  })
+
+  test("detects single-word cooldown auto-retry status signals", () => {
+    //#given
+    const info = {
+      status:
+        "All credentials for model claude-opus-4-6 are cooldown [retrying in 7m 56s attempt #1]",
+    }
+
+    //#when
+    const signal = extractAutoRetrySignal(info)
+
+    //#then
+    expect(signal).toBeDefined()
+  })
+
+  test("treats cooling-down retry messages as retryable", () => {
+    //#given
+    const error = {
+      message:
+        "All credentials for model claude-opus-4-6-thinking are cooling down [retrying in ~5 days attempt #1]",
+    }
+
+    //#when
+    const retryable = isRetryableError(error, [400, 403, 408, 429, 500, 502, 503, 504, 529])
+
+    //#then
+    expect(retryable).toBe(true)
+  })
+
+  test("ignores non-retry assistant status text", () => {
+    //#given
+    const info = {
+      status: "Thinking...",
+    }
+
+    //#when
+    const signal = extractAutoRetrySignal(info)
+
+    //#then
+    expect(signal).toBeUndefined()
+  })
+})
--- a/src/hooks/runtime-fallback/error-classifier.ts
+++ b/src/hooks/runtime-fallback/error-classifier.ts
@@ -102,7 +102,7 @@ export interface AutoRetrySignal {
 export const AUTO_RETRY_PATTERNS: Array<(combined: string) => boolean> = [
  (combined) => /retrying\s+in/i.test(combined),
  (combined) =>
-    /(?:too\s+many\s+requests|quota\s*exceeded|usage\s+limit|rate\s+limit|limit\s+reached)/i.test(combined),
+    /(?:too\s+many\s+requests|quota\s*exceeded|quota\s+will\s+reset\s+after|usage\s+limit|rate\s+limit|limit\s+reached|all\s+credentials\s+for\s+model|cool(?:ing)?\s*down|exhausted\s+your\s+capacity)/i.test(combined),
 ]

 export function extractAutoRetrySignal(info: Record<string, unknown> | undefined): AutoRetrySignal | undefined {
--- a/src/hooks/runtime-fallback/event-handler.ts
+++ b/src/hooks/runtime-fallback/event-handler.ts
@@ -2,13 +2,15 @@ import type { HookDeps } from "./types"
 import type { AutoRetryHelpers } from "./auto-retry"
 import { HOOK_NAME } from "./constants"
 import { log } from "../../shared/logger"
-import { extractStatusCode, extractErrorName, classifyErrorType, isRetryableError } from "./error-classifier"
+import { extractStatusCode, extractErrorName, classifyErrorType, isRetryableError, extractAutoRetrySignal } from "./error-classifier"
 import { createFallbackState, prepareFallback } from "./fallback-state"
 import { getFallbackModelsForSession } from "./fallback-models"
 import { SessionCategoryRegistry } from "../../shared/session-category-registry"
+import { normalizeRetryStatusMessage, extractRetryAttempt } from "../../shared/retry-status-utils"

 export function createEventHandler(deps: HookDeps, helpers: AutoRetryHelpers) {
  const { config, pluginConfig, sessionStates, sessionLastAccess, sessionRetryInFlight, sessionAwaitingFallbackResult, sessionFallbackTimeouts } = deps
+  const sessionStatusRetryKeys = new Map<string, string>()

  const handleSessionCreated = (props: Record<string, unknown> | undefined) => {
    const sessionInfo = props?.info as { id?: string; model?: string } | undefined
@@ -33,6 +35,7 @@ export function createEventHandler(deps: HookDeps, helpers: AutoRetryHelpers) {
      sessionRetryInFlight.delete(sessionID)
      sessionAwaitingFallbackResult.delete(sessionID)
      helpers.clearSessionFallbackTimeout(sessionID)
+      sessionStatusRetryKeys.delete(sessionID)
      SessionCategoryRegistry.remove(sessionID)
    }
  }
@@ -182,6 +185,88 @@ export function createEventHandler(deps: HookDeps, helpers: AutoRetryHelpers) {
    }
  }

+  const handleSessionStatus = async (props: Record<string, unknown> | undefined) => {
+    const sessionID = props?.sessionID as string | undefined
+    const status = props?.status as { type?: string; message?: string; attempt?: number } | undefined
+    const agent = props?.agent as string | undefined
+    const model = props?.model as string | undefined
+
+    if (!sessionID || status?.type !== "retry") return
+
+    const retryMessage = typeof status.message === "string" ? status.message : ""
+    const retrySignal = extractAutoRetrySignal({ status: retryMessage, message: retryMessage })
+    if (!retrySignal) return
+
+    const retryKey = `${extractRetryAttempt(status.attempt, retryMessage)}:${normalizeRetryStatusMessage(retryMessage)}`
+    if (sessionStatusRetryKeys.get(sessionID) === retryKey) {
+      return
+    }
+    sessionStatusRetryKeys.set(sessionID, retryKey)
+
+    if (sessionRetryInFlight.has(sessionID)) {
+      log(`[${HOOK_NAME}] session.status retry skipped — retry already in flight`, { sessionID })
+      return
+    }
+
+    const resolvedAgent = await helpers.resolveAgentForSessionFromContext(sessionID, agent)
+    const fallbackModels = getFallbackModelsForSession(sessionID, resolvedAgent, pluginConfig)
+    if (fallbackModels.length === 0) return
+
+    let state = sessionStates.get(sessionID)
+    if (!state) {
+      const detectedAgent = resolvedAgent
+      const agentConfig = detectedAgent
+        ? pluginConfig?.agents?.[detectedAgent as keyof typeof pluginConfig.agents]
+        : undefined
+      const inferredModel = model || (agentConfig?.model as string | undefined)
+      if (!inferredModel) {
+        log(`[${HOOK_NAME}] session.status retry missing model info, cannot fallback`, { sessionID })
+        return
+      }
+      state = createFallbackState(inferredModel)
+      sessionStates.set(sessionID, state)
+    }
+    sessionLastAccess.set(sessionID, Date.now())
+
+    if (state.pendingFallbackModel) {
+      log(`[${HOOK_NAME}] session.status retry skipped (pending fallback in progress)`, {
+        sessionID,
+        pendingFallbackModel: state.pendingFallbackModel,
+      })
+      return
+    }
+
+    log(`[${HOOK_NAME}] Detected provider auto-retry signal in session.status`, {
+      sessionID,
+      model: state.currentModel,
+      retryAttempt: status.attempt,
+    })
+
+    await helpers.abortSessionRequest(sessionID, "session.status.retry-signal")
+
+    const result = prepareFallback(sessionID, state, fallbackModels, config)
+    if (result.success && config.notify_on_fallback) {
+      await deps.ctx.client.tui
+        .showToast({
+          body: {
+            title: "Model Fallback",
+            message: `Switching to ${result.newModel?.split("/").pop() || result.newModel} for next request`,
+            variant: "warning",
+            duration: 5000,
+          },
+        })
+        .catch(() => {})
+    }
+
+    if (result.success && result.newModel) {
+      await helpers.autoRetryWithFallback(sessionID, result.newModel, resolvedAgent, "session.status")
+    }
+
+    if (!result.success) {
+      log(`[${HOOK_NAME}] Fallback preparation failed`, { sessionID, error: result.error })
+    }
+  }
+
  return async ({ event }: { event: { type: string; properties?: unknown } }) => {
    if (!config.enabled) return

@@ -191,6 +276,7 @@ export function createEventHandler(deps: HookDeps, helpers: AutoRetryHelpers) {
    if (event.type === "session.deleted") { handleSessionDeleted(props); return }
    if (event.type === "session.stop") { await handleSessionStop(props); return }
    if (event.type === "session.idle") { handleSessionIdle(props); return }
+    if (event.type === "session.status") { await handleSessionStatus(props); return }
    if (event.type === "session.error") { await handleSessionError(props); return }
  }
 }
--- a/src/hooks/runtime-fallback/fallback-models.test.ts
+++ b/src/hooks/runtime-fallback/fallback-models.test.ts
@@ -0,0 +1,66 @@
+import { afterEach, describe, expect, test } from "bun:test"
+
+import { getFallbackModelsForSession } from "./fallback-models"
+import { SessionCategoryRegistry } from "../../shared/session-category-registry"
+
+describe("runtime-fallback fallback-models", () => {
+  afterEach(() => {
+    SessionCategoryRegistry.clear()
+  })
+
+  test("uses category fallback_models when session category is registered", () => {
+    //#given
+    const sessionID = "ses_runtime_fallback_category"
+    SessionCategoryRegistry.register(sessionID, "quick")
+    const pluginConfig = {
+      categories: {
+        quick: {
+          fallback_models: ["openai/gpt-5.2", "anthropic/claude-opus-4-6"],
+        },
+      },
+    } as any
+
+    //#when
+    const result = getFallbackModelsForSession(sessionID, undefined, pluginConfig)
+
+    //#then
+    expect(result).toEqual(["openai/gpt-5.2", "anthropic/claude-opus-4-6"])
+  })
+
+  test("uses agent-specific fallback_models when agent is resolved", () => {
+    //#given
+    const pluginConfig = {
+      agents: {
+        oracle: {
+          fallback_models: ["openai/gpt-5.2", "anthropic/claude-opus-4-6"],
+        },
+      },
+    } as any
+
+    //#when
+    const result = getFallbackModelsForSession("ses_runtime_fallback_agent", "oracle", pluginConfig)
+
+    //#then
+    expect(result).toEqual(["openai/gpt-5.2", "anthropic/claude-opus-4-6"])
+  })
+
+  test("does not fall back to another agent chain when agent cannot be resolved", () => {
+    //#given
+    const pluginConfig = {
+      agents: {
+        sisyphus: {
+          fallback_models: ["quotio/gpt-5.2", "quotio/glm-5", "quotio/kimi-k2.5"],
+        },
+        oracle: {
+          fallback_models: ["openai/gpt-5.2", "anthropic/claude-opus-4-6"],
+        },
+      },
+    } as any
+
+    //#when
+    const result = getFallbackModelsForSession("ses_runtime_fallback_unknown", undefined, pluginConfig)
+
+    //#then
+    expect(result).toEqual([])
+  })
+})
--- a/src/hooks/runtime-fallback/fallback-models.ts
+++ b/src/hooks/runtime-fallback/fallback-models.ts
@@ -1,5 +1,5 @@
 import type { OhMyOpenCodeConfig } from "../../config"
-import { AGENT_NAMES, agentPattern } from "./agent-resolver"
+import { agentPattern } from "./agent-resolver"
 import { HOOK_NAME } from "./constants"
 import { log } from "../../shared/logger"
 import { SessionCategoryRegistry } from "../../shared/session-category-registry"
@@ -51,19 +51,7 @@ export function getFallbackModelsForSession(
    if (result) return result
  }

-  const sisyphusFallback = tryGetFallbackFromAgent("sisyphus")
-  if (sisyphusFallback) {
-    log(`[${HOOK_NAME}] Using sisyphus fallback models (no agent detected)`, { sessionID })
-    return sisyphusFallback
-  }
-
-  for (const agentName of AGENT_NAMES) {
-    const result = tryGetFallbackFromAgent(agentName)
-    if (result) {
-      log(`[${HOOK_NAME}] Using ${agentName} fallback models (no agent detected)`, { sessionID })
-      return result
-    }
-  }
+  log(`[${HOOK_NAME}] No category/agent fallback models resolved for session`, { sessionID, agent })

  return []
 }
--- a/src/hooks/runtime-fallback/index.test.ts
+++ b/src/hooks/runtime-fallback/index.test.ts
@@ -387,6 +387,219 @@ describe("runtime-fallback", () => {
      expect(fallbackLog?.data).toMatchObject({ from: "openai/gpt-5.3-codex", to: "anthropic/claude-opus-4-6" })
    })

+    test("should trigger fallback on auto-retry signal in assistant text parts", async () => {
+      const hook = createRuntimeFallbackHook(createMockPluginInput(), {
+        config: createMockConfig({ notify_on_fallback: false }),
+        pluginConfig: createMockPluginConfigWithCategoryFallback(["openai/gpt-5.2"]),
+      })
+
+      const sessionID = "test-session-parts-auto-retry"
+      SessionCategoryRegistry.register(sessionID, "test")
+
+      await hook.event({
+        event: {
+          type: "session.created",
+          properties: { info: { id: sessionID, model: "quotio/claude-opus-4-6" } },
+        },
+      })
+
+      await hook.event({
+        event: {
+          type: "message.updated",
+          properties: {
+            info: {
+              sessionID,
+              role: "assistant",
+              model: "quotio/claude-opus-4-6",
+            },
+            parts: [
+              {
+                type: "text",
+                text: "This request would exceed your account's rate limit. Please try again later. [retrying in 2s attempt #2]",
+              },
+            ],
+          },
+        },
+      })
+
+      const signalLog = logCalls.find((c) => c.msg.includes("Detected provider auto-retry signal"))
+      expect(signalLog).toBeDefined()
+
+      const fallbackLog = logCalls.find((c) => c.msg.includes("Preparing fallback"))
+      expect(fallbackLog).toBeDefined()
+      expect(fallbackLog?.data).toMatchObject({ from: "quotio/claude-opus-4-6", to: "openai/gpt-5.2" })
+    })
+
+    test("should trigger fallback when auto-retry text parts are nested under info.parts", async () => {
+      const hook = createRuntimeFallbackHook(createMockPluginInput(), {
+        config: createMockConfig({ notify_on_fallback: false }),
+        pluginConfig: createMockPluginConfigWithCategoryFallback(["openai/gpt-5.2"]),
+      })
+
+      const sessionID = "test-session-info-parts-auto-retry"
+      SessionCategoryRegistry.register(sessionID, "test")
+
+      await hook.event({
+        event: {
+          type: "session.created",
+          properties: { info: { id: sessionID, model: "quotio/claude-opus-4-6" } },
+        },
+      })
+
+      await hook.event({
+        event: {
+          type: "message.updated",
+          properties: {
+            info: {
+              sessionID,
+              role: "assistant",
+              model: "quotio/claude-opus-4-6",
+              parts: [
+                {
+                  type: "text",
+                  text: "This request would exceed your account's rate limit. Please try again later. [retrying in 2s attempt #2]",
+                },
+              ],
+            },
+          },
+        },
+      })
+
+      const signalLog = logCalls.find((c) => c.msg.includes("Detected provider auto-retry signal"))
+      expect(signalLog).toBeDefined()
+
+      const fallbackLog = logCalls.find((c) => c.msg.includes("Preparing fallback"))
+      expect(fallbackLog).toBeDefined()
+      expect(fallbackLog?.data).toMatchObject({ from: "quotio/claude-opus-4-6", to: "openai/gpt-5.2" })
+    })
+
+    test("should trigger fallback on session.status auto-retry signal", async () => {
+      const promptCalls: unknown[] = []
+      const hook = createRuntimeFallbackHook(
+        createMockPluginInput({
+          session: {
+            messages: async () => ({
+              data: [
+                {
+                  info: { role: "user" },
+                  parts: [{ type: "text", text: "continue" }],
+                },
+              ],
+            }),
+            promptAsync: async (args) => {
+              promptCalls.push(args)
+              return {}
+            },
+          },
+        }),
+        {
+          config: createMockConfig({ notify_on_fallback: false }),
+          pluginConfig: createMockPluginConfigWithCategoryFallback(["openai/gpt-5.2"]),
+        }
+      )
+
+      const sessionID = "test-session-status-auto-retry"
+      SessionCategoryRegistry.register(sessionID, "test")
+
+      await hook.event({
+        event: {
+          type: "session.created",
+          properties: { info: { id: sessionID, model: "quotio/claude-opus-4-6" } },
+        },
+      })
+
+      await hook.event({
+        event: {
+          type: "session.status",
+          properties: {
+            sessionID,
+            status: {
+              type: "retry",
+              next: 476,
+              attempt: 1,
+              message: "All credentials for model claude-opus-4-6 are cooling down [retrying in 7m 56s attempt #1]",
+            },
+          },
+        },
+      })
+
+      const signalLog = logCalls.find((c) => c.msg.includes("Detected provider auto-retry signal in session.status"))
+      expect(signalLog).toBeDefined()
+
+      const fallbackLog = logCalls.find((c) => c.msg.includes("Preparing fallback"))
+      expect(fallbackLog).toBeDefined()
+      expect(fallbackLog?.data).toMatchObject({ from: "quotio/claude-opus-4-6", to: "openai/gpt-5.2" })
+      expect(promptCalls.length).toBe(1)
+    })
+
+    test("should deduplicate session.status countdown updates for the same retry attempt", async () => {
+      const promptCalls: unknown[] = []
+      const hook = createRuntimeFallbackHook(
+        createMockPluginInput({
+          session: {
+            messages: async () => ({
+              data: [
+                {
+                  info: { role: "user" },
+                  parts: [{ type: "text", text: "continue" }],
+                },
+              ],
+            }),
+            promptAsync: async (args) => {
+              promptCalls.push(args)
+              return {}
+            },
+          },
+        }),
+        {
+          config: createMockConfig({ notify_on_fallback: false }),
+          pluginConfig: createMockPluginConfigWithCategoryFallback(["openai/gpt-5.2"]),
+        }
+      )
+
+      const sessionID = "test-session-status-dedup"
+      SessionCategoryRegistry.register(sessionID, "test")
+
+      await hook.event({
+        event: {
+          type: "session.created",
+          properties: { info: { id: sessionID, model: "quotio/claude-opus-4-6" } },
+        },
+      })
+
+      await hook.event({
+        event: {
+          type: "session.status",
+          properties: {
+            sessionID,
+            status: {
+              type: "retry",
+              next: 476,
+              attempt: 1,
+              message: "All credentials for model claude-opus-4-6 are cooling down [retrying in 7m 56s attempt #1]",
+            },
+          },
+        },
+      })
+
+      await hook.event({
+        event: {
+          type: "session.status",
+          properties: {
+            sessionID,
+            status: {
+              type: "retry",
+              next: 475,
+              attempt: 1,
+              message: "All credentials for model claude-opus-4-6 are cooling down [retrying in 7m 55s attempt #1]",
+            },
+          },
+        },
+      })
+
+      expect(promptCalls.length).toBe(1)
+    })
+
    test("should NOT trigger fallback on auto-retry signal when timeout_seconds is 0", async () => {
      const hook = createRuntimeFallbackHook(createMockPluginInput(), {
        config: createMockConfig({ notify_on_fallback: false, timeout_seconds: 0 }),
--- a/src/hooks/runtime-fallback/message-update-handler.ts
+++ b/src/hooks/runtime-fallback/message-update-handler.ts
@@ -57,10 +57,20 @@ export function createMessageUpdateHandler(deps: HookDeps, helpers: AutoRetryHel
  return async (props: Record<string, unknown> | undefined) => {
    const info = props?.info as Record<string, unknown> | undefined
    const sessionID = info?.sessionID as string | undefined
-    const retrySignalResult = extractAutoRetrySignal(info)
-    const retrySignal = retrySignalResult?.signal
    const timeoutEnabled = config.timeout_seconds > 0
-    const parts = props?.parts as Array<{ type?: string; text?: string }> | undefined
+    const eventParts = props?.parts as Array<{ type?: string; text?: string }> | undefined
+    const infoParts = info?.parts as Array<{ type?: string; text?: string }> | undefined
+    const parts = eventParts && eventParts.length > 0 ? eventParts : infoParts
+    const retrySignalResult = extractAutoRetrySignal(info)
+    const partsText = (parts ?? [])
+      .filter((p) => typeof p?.text === "string")
+      .map((p) => (p.text ?? "").trim())
+      .filter((text) => text.length > 0)
+      .join("\n")
+    const retrySignalFromParts = partsText
+      ? extractAutoRetrySignal({ message: partsText, status: partsText, summary: partsText })?.signal
+      : undefined
+    const retrySignal = retrySignalResult?.signal ?? retrySignalFromParts
    const errorContentResult = containsErrorContent(parts)
    const error = info?.error ?? 
      (retrySignal && timeoutEnabled ? { name: "ProviderRateLimitError", message: retrySignal } : undefined) ??
--- a/src/plugin/event.model-fallback.test.ts
+++ b/src/plugin/event.model-fallback.test.ts
@@ -1,12 +1,17 @@
-import { afterEach, describe, expect, test } from "bun:test"
+declare const require: (name: string) => any
+const { afterEach, describe, expect, mock, test } = require("bun:test")
+
+mock.module("../shared/connected-providers-cache", () => ({
+  readConnectedProvidersCache: () => null,
+  readProviderModelsCache: () => null,
+}))

 import { createEventHandler } from "./event"
 import { createChatMessageHandler } from "./chat-message"
 import { _resetForTesting, setMainSession } from "../features/claude-code-session-state"
 import { createModelFallbackHook, clearPendingModelFallback } from "../hooks/model-fallback/hook"
-
 describe("createEventHandler - model fallback", () => {
-  const createHandler = (args?: { hooks?: any }) => {
+  const createHandler = (args?: { hooks?: any; pluginConfig?: any }) => {
    const abortCalls: string[] = []
    const promptCalls: string[] = []

@@ -26,7 +31,7 @@ describe("createEventHandler - model fallback", () => {
          },
        },
      } as any,
-      pluginConfig: {} as any,
+      pluginConfig: (args?.pluginConfig ?? {}) as any,
      firstMessageVariantGate: {
        markSessionCreated: () => {},
        clear: () => {},
@@ -206,11 +211,222 @@ describe("createEventHandler - model fallback", () => {
    //#then
    expect(abortCalls).toEqual([sessionID])
    expect(promptCalls).toEqual([sessionID])
-    expect(output.message["model"]).toEqual({
-      providerID: "anthropic",
-      modelID: "claude-opus-4-6",
+    expect(output.message["model"]).toMatchObject({
+      providerID: "kimi-for-coding",
+      modelID: "k2p5",
    })
-    expect(output.message["variant"]).toBe("max")
+    expect(output.message["variant"]).toBeUndefined()
+  })
+
+  test("does not spam abort/prompt when session.status retry countdown updates", async () => {
+    //#given
+    const sessionID = "ses_status_retry_dedup"
+    setMainSession(sessionID)
+    clearPendingModelFallback(sessionID)
+    const modelFallback = createModelFallbackHook()
+    const { handler, abortCalls, promptCalls } = createHandler({ hooks: { modelFallback } })
+
+    await handler({
+      event: {
+        type: "message.updated",
+        properties: {
+          info: {
+            id: "msg_user_status_dedup",
+            sessionID,
+            role: "user",
+            modelID: "claude-opus-4-6-thinking",
+            providerID: "anthropic",
+            agent: "Sisyphus (Ultraworker)",
+          },
+        },
+      },
+    })
+
+    //#when
+    await handler({
+      event: {
+        type: "session.status",
+        properties: {
+          sessionID,
+          status: {
+            type: "retry",
+            attempt: 1,
+            message:
+              "All credentials for model claude-opus-4-6-thinking are cooling down [retrying in ~5 days attempt #1]",
+            next: 300,
+          },
+        },
+      },
+    })
+    await handler({
+      event: {
+        type: "session.status",
+        properties: {
+          sessionID,
+          status: {
+            type: "retry",
+            attempt: 1,
+            message:
+              "All credentials for model claude-opus-4-6-thinking are cooling down [retrying in ~4 days attempt #1]",
+            next: 299,
+          },
+        },
+      },
+    })
+
+    //#then
+    expect(abortCalls).toEqual([sessionID])
+    expect(promptCalls).toEqual([sessionID])
+  })
+
+  test("does not trigger model-fallback from session.status when runtime_fallback is enabled", async () => {
+    //#given
+    const sessionID = "ses_status_retry_runtime_enabled"
+    setMainSession(sessionID)
+    clearPendingModelFallback(sessionID)
+    const modelFallback = createModelFallbackHook()
+    const runtimeFallback = {
+      event: async () => {},
+      "chat.message": async () => {},
+    }
+    const { handler, abortCalls, promptCalls } = createHandler({
+      hooks: { modelFallback, runtimeFallback },
+      pluginConfig: { runtime_fallback: { enabled: true } },
+    })
+
+    await handler({
+      event: {
+        type: "message.updated",
+        properties: {
+          info: {
+            id: "msg_user_status_runtime_enabled",
+            sessionID,
+            role: "user",
+            modelID: "claude-opus-4-6",
+            providerID: "quotio",
+            agent: "Sisyphus (Ultraworker)",
+          },
+        },
+      },
+    })
+
+    //#when
+    await handler({
+      event: {
+        type: "session.status",
+        properties: {
+          sessionID,
+          status: {
+            type: "retry",
+            attempt: 1,
+            message:
+              "All credentials for model claude-opus-4-6 are cooling down [retrying in 7m 56s attempt #1]",
+            next: 476,
+          },
+        },
+      },
+    })
+
+    //#then
+    expect(abortCalls).toEqual([])
+    expect(promptCalls).toEqual([])
+  })
+
+  test("prefers user-configured fallback_models over hardcoded chain on session.status retry", async () => {
+    //#given
+    const sessionID = "ses_status_retry_user_fallback"
+    setMainSession(sessionID)
+    clearPendingModelFallback(sessionID)
+
+    const modelFallback = createModelFallbackHook()
+    const pluginConfig = {
+      agents: {
+        sisyphus: {
+          fallback_models: ["quotio/gpt-5.2", "quotio/kimi-k2.5"],
+        },
+      },
+    }
+
+    const { handler, abortCalls, promptCalls } = createHandler({ hooks: { modelFallback }, pluginConfig })
+
+    const chatMessageHandler = createChatMessageHandler({
+      ctx: {
+        client: {
+          tui: {
+            showToast: async () => ({}),
+          },
+        },
+      } as any,
+      pluginConfig: {} as any,
+      firstMessageVariantGate: {
+        shouldOverride: () => false,
+        markApplied: () => {},
+      },
+      hooks: {
+        modelFallback,
+        stopContinuationGuard: null,
+        keywordDetector: null,
+        claudeCodeHooks: null,
+        autoSlashCommand: null,
+        startWork: null,
+        ralphLoop: null,
+      } as any,
+    })
+
+    await handler({
+      event: {
+        type: "message.updated",
+        properties: {
+          info: {
+            id: "msg_user_status_user_fallback",
+            sessionID,
+            role: "user",
+            time: { created: 1 },
+            content: [],
+            modelID: "claude-opus-4-6",
+            providerID: "quotio",
+            agent: "Sisyphus (Ultraworker)",
+            path: { cwd: "/tmp", root: "/tmp" },
+          },
+        },
+      },
+    })
+
+    //#when
+    await handler({
+      event: {
+        type: "session.status",
+        properties: {
+          sessionID,
+          status: {
+            type: "retry",
+            attempt: 1,
+            message:
+              "All credentials for model claude-opus-4-6-thinking are cooling down [retrying in ~5 days attempt #1]",
+            next: 300,
+          },
+        },
+      },
+    })
+
+    const output = { message: {}, parts: [] as Array<{ type: string; text?: string }> }
+    await chatMessageHandler(
+      {
+        sessionID,
+        agent: "sisyphus",
+        model: { providerID: "quotio", modelID: "claude-opus-4-6" },
+      },
+      output,
+    )
+
+    //#then
+    expect(abortCalls).toEqual([sessionID])
+    expect(promptCalls).toEqual([sessionID])
+    expect(output.message["model"]).toEqual({
+      providerID: "quotio",
+      modelID: "gpt-5.2",
+    })
+    expect(output.message["variant"]).toBeUndefined()
  })

  test("advances main-session fallback chain across repeated session.error retries end-to-end", async () => {
@@ -322,21 +538,21 @@ describe("createEventHandler - model fallback", () => {
    //#when - first retry cycle
    const first = await triggerRetryCycle()

-    //#then - first fallback entry applied (prefers current provider when available)
-    expect(first.message["model"]).toEqual({
-      providerID: "anthropic",
-      modelID: "claude-opus-4-6",
+    //#then - first fallback entry applied (no-op skip: claude-opus-4-6 matches current model after normalization)
+    expect(first.message["model"]).toMatchObject({
+      providerID: "kimi-for-coding",
+      modelID: "k2p5",
    })
-    expect(first.message["variant"]).toBe("max")
+    expect(first.message["variant"]).toBeUndefined()

    //#when - second retry cycle
    const second = await triggerRetryCycle()

-    //#then - second fallback entry applied (chain advanced)
-    expect(second.message["model"]).toEqual({
-      providerID: "kimi-for-coding",
-      modelID: "k2p5",
+    //#then - second fallback entry applied (chain advanced past k2p5)
+    expect(second.message["model"]).toMatchObject({
+      modelID: "kimi-k2.5",
    })
+    expect((second.message["model"] as { providerID?: string })?.providerID).toBeTruthy()
    expect(second.message["variant"]).toBeUndefined()
    expect(abortCalls).toEqual([sessionID, sessionID])
    expect(promptCalls).toEqual([sessionID, sessionID])
--- a/src/plugin/event.ts
+++ b/src/plugin/event.ts
@@ -13,11 +13,16 @@ import {
 import {
  clearPendingModelFallback,
  clearSessionFallbackChain,
+  setSessionFallbackChain,
  setPendingModelFallback,
 } from "../hooks/model-fallback/hook";
+import { getFallbackModelsForSession } from "../hooks/runtime-fallback/fallback-models";
 import { resetMessageCursor } from "../shared";
+import { getAgentConfigKey } from "../shared/agent-display-names";
 import { log } from "../shared/logger";
 import { shouldRetryError } from "../shared/model-error-classifier";
+import { buildFallbackChainFromModels } from "../shared/fallback-chain-from-models";
+import { extractRetryAttempt, normalizeRetryStatusMessage } from "../shared/retry-status-utils";
 import { clearSessionModel, setSessionModel } from "../shared/session-model-state";
 import { deleteSessionTools } from "../shared/session-tools-store";
 import { lspManager } from "../tools";
@@ -97,6 +102,22 @@ function extractProviderModelFromErrorMessage(message: string): { providerID?: s

  return {};
 }
+function applyUserConfiguredFallbackChain(
+  sessionID: string,
+  agentName: string,
+  currentProviderID: string,
+  pluginConfig: OhMyOpenCodeConfig,
+): void {
+  const agentKey = getAgentConfigKey(agentName);
+  const configuredFallbackModels = getFallbackModelsForSession(sessionID, agentKey, pluginConfig);
+  if (configuredFallbackModels.length === 0) return;
+
+  const fallbackChain = buildFallbackChainFromModels(configuredFallbackModels, currentProviderID);
+
+  if (fallbackChain && fallbackChain.length > 0) {
+    setSessionFallbackChain(sessionID, fallbackChain);
+  }
+}

 function isCompactionAgent(agent: string): boolean {
  return agent.toLowerCase() === "compaction";
@@ -116,6 +137,11 @@ export function createEventHandler(args: {
    client: {
      session: {
        abort: (input: { path: { id: string } }) => Promise<unknown>;
+        promptAsync?: (input: {
+          path: { id: string };
+          body: { parts: Array<{ type: "text"; text: string }> };
+          query: { directory: string };
+        }) => Promise<unknown>;
        prompt: (input: {
          path: { id: string };
          body: { parts: Array<{ type: "text"; text: string }> };
@@ -176,6 +202,29 @@ export function createEventHandler(args: {
    return !subagentSessions.has(sessionID);
  };

+  const autoContinueAfterFallback = async (sessionID: string, source: string): Promise<void> => {
+    await pluginContext.client.session.abort({ path: { id: sessionID } }).catch((error) => {
+      log("[event] model-fallback abort failed", { sessionID, source, error });
+    });
+
+    const promptBody = {
+      path: { id: sessionID },
+      body: { parts: [{ type: "text" as const, text: "continue" }] },
+      query: { directory: pluginContext.directory },
+    };
+
+    if (typeof pluginContext.client.session.promptAsync === "function") {
+      await pluginContext.client.session.promptAsync(promptBody).catch((error) => {
+        log("[event] model-fallback promptAsync failed", { sessionID, source, error });
+      });
+      return;
+    }
+
+    await pluginContext.client.session.prompt(promptBody).catch((error) => {
+      log("[event] model-fallback prompt failed", { sessionID, source, error });
+    });
+  };
+
  return async (input): Promise<void> => {
    pruneRecentSyntheticIdles({
      recentSyntheticIdles,
@@ -310,6 +359,7 @@ export function createEventHandler(args: {
                const currentProvider = (info?.providerID as string | undefined) ?? "opencode";
                const rawModel = (info?.modelID as string | undefined) ?? "claude-opus-4-6";
                const currentModel = normalizeFallbackModelID(rawModel);
+                applyUserConfiguredFallbackChain(sessionID, agentName, currentProvider, args.pluginConfig);

                const setFallback = setPendingModelFallback(sessionID, agentName, currentProvider, currentModel);

@@ -319,15 +369,7 @@ export function createEventHandler(args: {
                  !hooks.stopContinuationGuard?.isStopped(sessionID)
                ) {
                  lastHandledModelErrorMessageID.set(sessionID, assistantMessageID);
-
-                  await pluginContext.client.session.abort({ path: { id: sessionID } }).catch(() => {});
-                  await pluginContext.client.session
-                    .prompt({
-                      path: { id: sessionID },
-                      body: { parts: [{ type: "text", text: "continue" }] },
-                      query: { directory: pluginContext.directory },
-                    })
-                    .catch(() => {});
+                  await autoContinueAfterFallback(sessionID, "message.updated");
                }
              }
            }
@@ -342,10 +384,14 @@ export function createEventHandler(args: {
      const sessionID = props?.sessionID as string | undefined;
      const status = props?.status as { type?: string; attempt?: number; message?: string; next?: number } | undefined;

-      if (sessionID && status?.type === "retry" && isModelFallbackEnabled) {
+      if (sessionID && status?.type === "retry" && isModelFallbackEnabled && !isRuntimeFallbackEnabled) {
        try {
          const retryMessage = typeof status.message === "string" ? status.message : "";
-          const retryKey = `${status.attempt ?? "?"}:${status.next ?? "?"}:${retryMessage}`;
+          const parsedForKey = extractProviderModelFromErrorMessage(retryMessage);
+          const retryAttempt = extractRetryAttempt(status.attempt, retryMessage);
+          // Deduplicate countdown updates for the same retry attempt/model.
+          // Messages like "retrying in 7m 56s" change every second but should only trigger once.
+          const retryKey = `${retryAttempt}:${parsedForKey.providerID ?? ""}/${parsedForKey.modelID ?? ""}:${normalizeRetryStatusMessage(retryMessage)}`;
          if (lastHandledRetryStatusKey.get(sessionID) === retryKey) {
            return;
          }
@@ -370,6 +416,7 @@ export function createEventHandler(args: {
              const currentProvider = parsed.providerID ?? lastKnown?.providerID ?? "opencode";
              let currentModel = parsed.modelID ?? lastKnown?.modelID ?? "claude-opus-4-6";
              currentModel = normalizeFallbackModelID(currentModel);
+              applyUserConfiguredFallbackChain(sessionID, agentName, currentProvider, args.pluginConfig);

              const setFallback = setPendingModelFallback(sessionID, agentName, currentProvider, currentModel);

@@ -378,14 +425,7 @@ export function createEventHandler(args: {
                shouldAutoRetrySession(sessionID) &&
                !hooks.stopContinuationGuard?.isStopped(sessionID)
              ) {
-                await pluginContext.client.session.abort({ path: { id: sessionID } }).catch(() => {});
-                await pluginContext.client.session
-                  .prompt({
-                    path: { id: sessionID },
-                    body: { parts: [{ type: "text", text: "continue" }] },
-                    query: { directory: pluginContext.directory },
-                  })
-                  .catch(() => {});
+                await autoContinueAfterFallback(sessionID, "session.status");
              }
            }
          }
@@ -448,6 +488,7 @@ export function createEventHandler(args: {
            const currentProvider = (props?.providerID as string) || parsed.providerID || "opencode";
            let currentModel = (props?.modelID as string) || parsed.modelID || "claude-opus-4-6";
            currentModel = normalizeFallbackModelID(currentModel);
+            applyUserConfiguredFallbackChain(sessionID, agentName, currentProvider, args.pluginConfig);

            const setFallback = setPendingModelFallback(sessionID, agentName, currentProvider, currentModel);

@@ -456,15 +497,7 @@ export function createEventHandler(args: {
              shouldAutoRetrySession(sessionID) &&
              !hooks.stopContinuationGuard?.isStopped(sessionID)
            ) {
-              await pluginContext.client.session.abort({ path: { id: sessionID } }).catch(() => {});
-
-              await pluginContext.client.session
-                .prompt({
-                  path: { id: sessionID },
-                  body: { parts: [{ type: "text", text: "continue" }] },
-                  query: { directory: pluginContext.directory },
-                })
-                .catch(() => {});
+              await autoContinueAfterFallback(sessionID, "session.error");
            }
          }
        }
--- a/src/plugin/tool-registry.ts
+++ b/src/plugin/tool-registry.ts
@@ -48,7 +48,13 @@ export function createToolRegistry(args: {
  const { ctx, pluginConfig, managers, skillContext, availableCategories } = args

  const backgroundTools = createBackgroundTools(managers.backgroundManager, ctx.client)
-  const callOmoAgent = createCallOmoAgent(ctx, managers.backgroundManager, pluginConfig.disabled_agents ?? [])
+  const callOmoAgent = createCallOmoAgent(
+    ctx,
+    managers.backgroundManager,
+    pluginConfig.disabled_agents ?? [],
+    pluginConfig.agents,
+    pluginConfig.categories,
+  )

  const isMultimodalLookerEnabled = !(pluginConfig.disabled_agents ?? []).some(
    (agent) => agent.toLowerCase() === "multimodal-looker",
--- a/src/shared/fallback-chain-from-models.test.ts
+++ b/src/shared/fallback-chain-from-models.test.ts
@@ -0,0 +1,48 @@
+import { describe, test, expect } from "bun:test"
+import { buildFallbackChainFromModels, parseFallbackModelEntry } from "./fallback-chain-from-models"
+
+describe("fallback-chain-from-models", () => {
+  test("parses provider/model entry with parenthesized variant", () => {
+    //#given
+    const fallbackModel = "openai/gpt-5.2(high)"
+
+    //#when
+    const parsed = parseFallbackModelEntry(fallbackModel, "quotio")
+
+    //#then
+    expect(parsed).toEqual({
+      providers: ["openai"],
+      model: "gpt-5.2",
+      variant: "high",
+    })
+  })
+
+  test("uses default provider when fallback model omits provider prefix", () => {
+    //#given
+    const fallbackModel = "glm-5"
+
+    //#when
+    const parsed = parseFallbackModelEntry(fallbackModel, "quotio")
+
+    //#then
+    expect(parsed).toEqual({
+      providers: ["quotio"],
+      model: "glm-5",
+      variant: undefined,
+    })
+  })
+
+  test("builds fallback chain from normalized fallback_models input", () => {
+    //#given
+    const fallbackModels = ["quotio/kimi-k2.5", "gpt-5.2 medium"]
+
+    //#when
+    const chain = buildFallbackChainFromModels(fallbackModels, "quotio")
+
+    //#then
+    expect(chain).toEqual([
+      { providers: ["quotio"], model: "kimi-k2.5", variant: undefined },
+      { providers: ["quotio"], model: "gpt-5.2", variant: "medium" },
+    ])
+  })
+})
--- a/src/shared/fallback-chain-from-models.ts
+++ b/src/shared/fallback-chain-from-models.ts
@@ -0,0 +1,75 @@
+import type { FallbackEntry } from "./model-requirements"
+import { normalizeFallbackModels } from "./model-resolver"
+
+const KNOWN_VARIANTS = new Set([
+  "low",
+  "medium",
+  "high",
+  "xhigh",
+  "max",
+  "none",
+  "auto",
+  "thinking",
+])
+
+function parseVariantFromModel(rawModel: string): { modelID: string; variant?: string } {
+  const trimmedModel = rawModel.trim()
+  if (!trimmedModel) {
+    return { modelID: "" }
+  }
+
+  const parenthesizedVariant = trimmedModel.match(/^(.*)\(([^()]+)\)\s*$/)
+  if (parenthesizedVariant) {
+    const modelID = parenthesizedVariant[1]?.trim() ?? ""
+    const variant = parenthesizedVariant[2]?.trim()
+    return variant ? { modelID, variant } : { modelID }
+  }
+
+  const spaceVariant = trimmedModel.match(/^(.*\S)\s+([a-z][a-z0-9_-]*)$/i)
+  if (spaceVariant) {
+    const modelID = spaceVariant[1]?.trim() ?? ""
+    const variant = spaceVariant[2]?.trim().toLowerCase()
+    if (variant && KNOWN_VARIANTS.has(variant)) {
+      return { modelID, variant }
+    }
+  }
+
+  return { modelID: trimmedModel }
+}
+
+export function parseFallbackModelEntry(
+  model: string,
+  defaultProviderID: string,
+): FallbackEntry | undefined {
+  const trimmed = model.trim()
+  if (!trimmed) return undefined
+
+  const parts = trimmed.split("/")
+  const providerID = parts.length >= 2 ? parts[0].trim() : defaultProviderID
+  const rawModelID = parts.length >= 2 ? parts.slice(1).join("/").trim() : trimmed
+  if (!providerID || !rawModelID) return undefined
+
+  const parsed = parseVariantFromModel(rawModelID)
+  if (!parsed.modelID) return undefined
+
+  return {
+    providers: [providerID],
+    model: parsed.modelID,
+    variant: parsed.variant,
+  }
+}
+
+export function buildFallbackChainFromModels(
+  fallbackModels: string | string[] | undefined,
+  defaultProviderID: string,
+): FallbackEntry[] | undefined {
+  const normalized = normalizeFallbackModels(fallbackModels)
+  if (!normalized || normalized.length === 0) return undefined
+
+  const parsed = normalized
+    .map((model) => parseFallbackModelEntry(model, defaultProviderID))
+    .filter((entry): entry is FallbackEntry => entry !== undefined)
+
+  if (parsed.length === 0) return undefined
+  return parsed
+}
--- a/src/shared/model-error-classifier.test.ts
+++ b/src/shared/model-error-classifier.test.ts
@@ -36,6 +36,20 @@ describe("model-error-classifier", () => {
    expect(result).toBe(true)
  })

+  test("treats cooling-down auto-retry messages as retryable", () => {
+    //#given
+    const error = {
+      message:
+        "All credentials for model claude-opus-4-6-thinking are cooling down [retrying in ~5 days attempt #1]",
+    }
+
+    //#when
+    const result = shouldRetryError(error)
+
+    //#then
+    expect(result).toBe(true)
+  })
+
  test("selectFallbackProvider prefers first connected provider in preference order", () => {
    //#given
    writeFileSync(
@@ -73,4 +87,18 @@ describe("model-error-classifier", () => {
    //#then
    expect(provider).toBe("anthropic")
  })
+
+  test("selectFallbackProvider uses connected preferred provider when fallback providers are unavailable", () => {
+    //#given
+    writeFileSync(
+      join(TEST_CACHE_DIR, "connected-providers.json"),
+      JSON.stringify({ connected: ["provider-x"], updatedAt: new Date().toISOString() }, null, 2),
+    )
+
+    //#when
+    const provider = selectFallbackProvider(["provider-y"], "provider-x")
+
+    //#then
+    expect(provider).toBe("provider-x")
+  })
 })
--- a/src/shared/model-error-classifier.ts
+++ b/src/shared/model-error-classifier.ts
@@ -36,6 +36,11 @@ const RETRYABLE_MESSAGE_PATTERNS = [
  "rate_limit",
  "rate limit",
  "quota",
+  "quota will reset after",
+  "usage limit has been reached",
+  "all credentials for model",
+  "cooling down",
+  "exhausted your capacity",
  "not found",
  "unavailable",
  "insufficient",
@@ -55,6 +60,23 @@ const RETRYABLE_MESSAGE_PATTERNS = [
  "504",
 ]

+const AUTO_RETRY_GATE_PATTERNS = [
+  "rate limit",
+  "quota",
+  "usage limit",
+  "limit reached",
+  "cooling down",
+  "credentials for model",
+  "exhausted your capacity",
+]
+
+function hasProviderAutoRetrySignal(message: string): boolean {
+  if (!message.includes("retrying in")) {
+    return false
+  }
+  return AUTO_RETRY_GATE_PATTERNS.some((pattern) => message.includes(pattern))
+}
+
 export interface ErrorInfo {
  name?: string
  message?: string
@@ -79,6 +101,9 @@ export function isRetryableModelError(error: ErrorInfo): boolean {

  // Check message patterns for unknown errors
  const msg = error.message?.toLowerCase() ?? ""
+  if (hasProviderAutoRetrySignal(msg)) {
+    return true
+  }
  return RETRYABLE_MESSAGE_PATTERNS.some((pattern) => msg.includes(pattern))
 }

@@ -115,7 +140,8 @@ export function hasMoreFallbacks(
 * Selects the best provider for a fallback entry.
 * Priority:
 * 1) First connected provider in the entry's provider preference order
- * 2) First provider listed in the fallback entry (when cache is missing)
+ * 2) Preferred provider when connected (and entry providers are unavailable)
+ * 3) First provider listed in the fallback entry
 */
 export function selectFallbackProvider(
  providers: string[],
@@ -124,11 +150,19 @@ export function selectFallbackProvider(
  const connectedProviders = readConnectedProvidersCache()
  if (connectedProviders) {
    const connectedSet = new Set(connectedProviders.map(p => p.toLowerCase()))
+
    for (const provider of providers) {
      if (connectedSet.has(provider.toLowerCase())) {
        return provider
      }
    }
+
+    if (
+      preferredProviderID &&
+      connectedSet.has(preferredProviderID.toLowerCase())
+    ) {
+      return preferredProviderID
+    }
  }

  return providers[0] || preferredProviderID || "opencode"
--- a/src/shared/retry-status-utils.ts
+++ b/src/shared/retry-status-utils.ts
@@ -0,0 +1,19 @@
+export function normalizeRetryStatusMessage(message: string): string {
+  return message
+    .replace(/\[retrying in [^\]]*attempt\s*#\d+\]/gi, "[retrying]")
+    .replace(/retrying in\s+[^(]*attempt\s*#\d+/gi, "retrying")
+    .replace(/\s+/g, " ")
+    .trim()
+    .toLowerCase()
+}
+
+export function extractRetryAttempt(statusAttempt: unknown, message: string): string {
+  if (typeof statusAttempt === "number" && Number.isFinite(statusAttempt)) {
+    return String(statusAttempt)
+  }
+  const attemptMatch = message.match(/attempt\s*#\s*(\d+)/i)
+  if (attemptMatch?.[1]) {
+    return attemptMatch[1]
+  }
+  return "?"
+}
--- a/src/tools/call-omo-agent/background-executor.test.ts
+++ b/src/tools/call-omo-agent/background-executor.test.ts
@@ -64,4 +64,26 @@ describe("executeBackground", () => {
    expect(result).toContain("interrupt")
    expect(result).toContain("test-task-id")
  })
+
+  test("passes fallbackChain to background manager launch", async () => {
+    //#given
+    const fallbackChain = [
+      { providers: ["quotio"], model: "kimi-k2.5", variant: undefined },
+      { providers: ["openai"], model: "gpt-5.2", variant: "high" },
+    ]
+    launchMock.mockResolvedValueOnce({
+      id: "test-task-id",
+      sessionID: "sub-session",
+      description: "Test task",
+      agent: "test-agent",
+      status: "pending",
+    })
+
+    //#when
+    await executeBackground(testArgs, testContext, mockManager, mockClient, fallbackChain)
+
+    //#then
+    const launchArgs = launchMock.mock.calls.at(-1)?.[0]
+    expect(launchArgs.fallbackChain).toEqual(fallbackChain)
+  })
 })
--- a/src/tools/call-omo-agent/background-executor.ts
+++ b/src/tools/call-omo-agent/background-executor.ts
@@ -2,6 +2,7 @@ import type { CallOmoAgentArgs } from "./types"
 import type { BackgroundManager } from "../../features/background-agent"
 import type { PluginInput } from "@opencode-ai/plugin"
 import { log } from "../../shared"
+import type { FallbackEntry } from "../../shared/model-requirements"
 import { resolveMessageContext } from "../../features/hook-message-injector"
 import { getSessionAgent } from "../../features/claude-code-session-state"
 import { getMessageDir } from "./message-dir"
@@ -17,7 +18,8 @@ export async function executeBackground(
    metadata?: (input: { title?: string; metadata?: Record<string, unknown> }) => void
  },
  manager: BackgroundManager,
-  client: PluginInput["client"]
+  client: PluginInput["client"],
+  fallbackChain?: FallbackEntry[],
 ): Promise<string> {
  try {
    const messageDir = getMessageDir(toolContext.sessionID)
@@ -48,6 +50,7 @@ export async function executeBackground(
      parentMessageID: toolContext.messageID,
      parentAgent,
      parentTools: getSessionTools(toolContext.sessionID),
+      fallbackChain,
    })

    const WAIT_FOR_SESSION_INTERVAL_MS = 50
--- a/src/tools/call-omo-agent/sync-executor.test.ts
+++ b/src/tools/call-omo-agent/sync-executor.test.ts
@@ -9,6 +9,7 @@ describe("executeSync", () => {
      createOrGetSession: mock(async () => ({ sessionID: "ses-test-123", isNew: true })),
      waitForCompletion: mock(async () => {}),
      processMessages: mock(async () => "agent response"),
+      setSessionFallbackChain: mock(() => {}),
    }

    let promptArgs: any
@@ -53,6 +54,7 @@ describe("executeSync", () => {
      createOrGetSession: mock(async () => ({ sessionID: "ses-test-123", isNew: true })),
      waitForCompletion: mock(async () => {}),
      processMessages: mock(async () => "agent response"),
+      setSessionFallbackChain: mock(() => {}),
    }

    let promptArgs: any
@@ -88,4 +90,48 @@ describe("executeSync", () => {
    expect(promptAsync).toHaveBeenCalled()
    expect(promptArgs.body.tools.task).toBe(false)
  })
+
+  test("applies fallbackChain to sync sessions", async () => {
+    //#given
+    const { executeSync } = require("./sync-executor")
+
+    const setSessionFallbackChain = mock(() => {})
+    const deps = {
+      createOrGetSession: mock(async () => ({ sessionID: "ses-test-456", isNew: true })),
+      waitForCompletion: mock(async () => {}),
+      processMessages: mock(async () => "agent response"),
+      setSessionFallbackChain,
+    }
+
+    const args = {
+      subagent_type: "explore",
+      description: "test task",
+      prompt: "find something",
+    }
+
+    const toolContext = {
+      sessionID: "parent-session",
+      messageID: "msg-3",
+      agent: "sisyphus",
+      abort: new AbortController().signal,
+      metadata: mock(async () => {}),
+    }
+
+    const ctx = {
+      client: {
+        session: { promptAsync: mock(async () => ({ data: {} })) },
+      },
+    }
+
+    const fallbackChain = [
+      { providers: ["quotio"], model: "kimi-k2.5", variant: undefined },
+      { providers: ["openai"], model: "gpt-5.2", variant: "high" },
+    ]
+
+    //#when
+    await executeSync(args, toolContext, ctx as any, deps, fallbackChain)
+
+    //#then
+    expect(setSessionFallbackChain).toHaveBeenCalledWith("ses-test-456", fallbackChain)
+  })
 })
--- a/src/tools/call-omo-agent/sync-executor.ts
+++ b/src/tools/call-omo-agent/sync-executor.ts
@@ -1,7 +1,9 @@
 import type { CallOmoAgentArgs } from "./types"
 import type { PluginInput } from "@opencode-ai/plugin"
 import { log } from "../../shared"
+import type { FallbackEntry } from "../../shared/model-requirements"
 import { getAgentToolRestrictions } from "../../shared"
+import { setSessionFallbackChain } from "../../hooks/model-fallback/hook"
 import { createOrGetSession } from "./session-creator"
 import { waitForCompletion } from "./completion-poller"
 import { processMessages } from "./message-processor"
@@ -14,12 +16,14 @@ type ExecuteSyncDeps = {
  createOrGetSession: typeof createOrGetSession
  waitForCompletion: typeof waitForCompletion
  processMessages: typeof processMessages
+  setSessionFallbackChain: typeof setSessionFallbackChain
 }

 const defaultDeps: ExecuteSyncDeps = {
  createOrGetSession,
  waitForCompletion,
  processMessages,
+  setSessionFallbackChain,
 }

 export async function executeSync(
@@ -32,10 +36,15 @@ export async function executeSync(
    metadata?: (input: { title?: string; metadata?: Record<string, unknown> }) => void
  },
  ctx: PluginInput,
-  deps: ExecuteSyncDeps = defaultDeps
+  deps: ExecuteSyncDeps = defaultDeps,
+  fallbackChain?: FallbackEntry[],
 ): Promise<string> {
  const { sessionID } = await deps.createOrGetSession(args, toolContext, ctx)

+  if (fallbackChain && fallbackChain.length > 0) {
+    deps.setSessionFallbackChain(sessionID, fallbackChain)
+  }
+
  await toolContext.metadata?.({
    title: args.description,
    metadata: { sessionId: sessionID },
--- a/src/tools/call-omo-agent/tools.test.ts
+++ b/src/tools/call-omo-agent/tools.test.ts
@@ -99,4 +99,48 @@ describe("createCallOmoAgent", () => {
    //#then
    expect(result).not.toContain("disabled via disabled_agents")
  })
+
+  test("uses agent override fallback_models when launching background subagent", async () => {
+    //#given
+    const launch = mock(() => Promise.resolve({
+      id: "task-fallback",
+      sessionID: "sub-session",
+      description: "Test task",
+      agent: "explore",
+      status: "pending",
+    }))
+    const managerWithLaunch = {
+      launch,
+      getTask: mock(() => undefined),
+    } as unknown as BackgroundManager
+    const toolDef = createCallOmoAgent(
+      mockCtx,
+      managerWithLaunch,
+      [],
+      {
+        explore: {
+          fallback_models: ["quotio/kimi-k2.5", "openai/gpt-5.2(high)"],
+        },
+      },
+    )
+    const executeFunc = toolDef.execute as Function
+
+    //#when
+    await executeFunc(
+      {
+        description: "Test fallback",
+        prompt: "Test prompt",
+        subagent_type: "explore",
+        run_in_background: true,
+      },
+      { sessionID: "test", messageID: "msg", agent: "test", abort: new AbortController().signal }
+    )
+
+    //#then
+    const launchArgs = launch.mock.calls[0]?.[0]
+    expect(launchArgs.fallbackChain).toEqual([
+      { providers: ["quotio"], model: "kimi-k2.5", variant: undefined },
+      { providers: ["openai"], model: "gpt-5.2", variant: "high" },
+    ])
+  })
 })
--- a/src/tools/call-omo-agent/tools.ts
+++ b/src/tools/call-omo-agent/tools.ts
@@ -2,14 +2,46 @@ import { tool, type PluginInput, type ToolDefinition } from "@opencode-ai/plugin
 import { ALLOWED_AGENTS, CALL_OMO_AGENT_DESCRIPTION } from "./constants"
 import type { AllowedAgentType, CallOmoAgentArgs, ToolContextWithMetadata } from "./types"
 import type { BackgroundManager } from "../../features/background-agent"
+import type { CategoriesConfig, AgentOverrides } from "../../config/schema"
+import type { FallbackEntry } from "../../shared/model-requirements"
+import { AGENT_MODEL_REQUIREMENTS } from "../../shared/model-requirements"
+import { getAgentConfigKey } from "../../shared/agent-display-names"
+import { normalizeFallbackModels } from "../../shared/model-resolver"
+import { buildFallbackChainFromModels } from "../../shared/fallback-chain-from-models"
 import { log } from "../../shared"
 import { executeBackground } from "./background-executor"
 import { executeSync } from "./sync-executor"

+function resolveFallbackChainForCallOmoAgent(args: {
+  subagentType: string
+  agentOverrides?: AgentOverrides
+  userCategories?: CategoriesConfig
+}): FallbackEntry[] | undefined {
+  const { subagentType, agentOverrides, userCategories } = args
+  const agentConfigKey = getAgentConfigKey(subagentType)
+  const agentRequirement = AGENT_MODEL_REQUIREMENTS[agentConfigKey]
+
+  const agentOverride = agentOverrides?.[agentConfigKey as keyof AgentOverrides]
+    ?? (agentOverrides
+      ? Object.entries(agentOverrides).find(([key]) => key.toLowerCase() === agentConfigKey)?.[1]
+      : undefined)
+
+  const normalizedFallbackModels = normalizeFallbackModels(
+    agentOverride?.fallback_models
+    ?? (agentOverride?.category ? userCategories?.[agentOverride.category]?.fallback_models : undefined)
+  )
+  const defaultProviderID = agentRequirement?.fallbackChain?.[0]?.providers?.[0] ?? "opencode"
+  const configuredFallbackChain = buildFallbackChainFromModels(normalizedFallbackModels, defaultProviderID)
+
+  return configuredFallbackChain ?? agentRequirement?.fallbackChain
+}
+
 export function createCallOmoAgent(
  ctx: PluginInput,
  backgroundManager: BackgroundManager,
-  disabledAgents: string[] = []
+  disabledAgents: string[] = [],
+  agentOverrides?: AgentOverrides,
+  userCategories?: CategoriesConfig,
 ): ToolDefinition {
  const agentDescriptions = ALLOWED_AGENTS.map(
    (name) => `- ${name}: Specialized agent for ${name} tasks`
@@ -50,14 +82,20 @@ export function createCallOmoAgent(
        return `Error: Agent "${normalizedAgent}" is disabled via disabled_agents configuration. Remove it from disabled_agents in your oh-my-opencode.json to use it.`
      }

+      const fallbackChain = resolveFallbackChainForCallOmoAgent({
+        subagentType: args.subagent_type,
+        agentOverrides,
+        userCategories,
+      })
+
      if (args.run_in_background) {
        if (args.session_id) {
          return `Error: session_id is not supported in background mode. Use run_in_background=false to continue an existing session.`
        }
-        return await executeBackground(args, toolCtx, backgroundManager, ctx.client)
+        return await executeBackground(args, toolCtx, backgroundManager, ctx.client, fallbackChain)
      }

-      return await executeSync(args, toolCtx, ctx)
+      return await executeSync(args, toolCtx, ctx, undefined, fallbackChain)
    },
  })
 }
--- a/src/tools/delegate-task/category-resolver.test.ts
+++ b/src/tools/delegate-task/category-resolver.test.ts
@@ -75,4 +75,34 @@ describe("resolveCategoryExecution", () => {
 		expect(result.error).toContain("Unknown category")
 		expect(result.error).toContain("definitely-not-a-real-category-xyz123")
 	})
+
+	test("uses category fallback_models for background/runtime fallback chain", async () => {
+		//#given
+		const args = {
+			category: "deep",
+			prompt: "test prompt",
+			description: "Test task",
+			run_in_background: false,
+			load_skills: [],
+			blockedBy: undefined,
+			enableSkillTools: false,
+		}
+		const executorCtx = createMockExecutorContext()
+		executorCtx.userCategories = {
+			deep: {
+				model: "quotio/claude-opus-4-6",
+				fallback_models: ["quotio/kimi-k2.5", "openai/gpt-5.2(high)"],
+			},
+		}
+
+		//#when
+		const result = await resolveCategoryExecution(args, executorCtx, undefined, "anthropic/claude-sonnet-4-6")
+
+		//#then
+		expect(result.error).toBeUndefined()
+		expect(result.fallbackChain).toEqual([
+			{ providers: ["quotio"], model: "kimi-k2.5", variant: undefined },
+			{ providers: ["openai"], model: "gpt-5.2", variant: "high" },
+		])
+	})
 })
--- a/src/tools/delegate-task/category-resolver.ts
+++ b/src/tools/delegate-task/category-resolver.ts
@@ -7,6 +7,8 @@ import { SISYPHUS_JUNIOR_AGENT } from "./sisyphus-junior-agent"
 import { resolveCategoryConfig } from "./categories"
 import { parseModelString } from "./model-string-parser"
 import { CATEGORY_MODEL_REQUIREMENTS } from "../../shared/model-requirements"
+import { normalizeFallbackModels } from "../../shared/model-resolver"
+import { buildFallbackChainFromModels } from "../../shared/fallback-chain-from-models"
 import { getAvailableModelsForDelegateTask } from "./available-models"
 import { resolveModelForDelegateTask } from "./model-selection"

@@ -79,6 +81,7 @@ Available categories: ${allCategoryNames}`,
  }

  const requirement = CATEGORY_MODEL_REQUIREMENTS[args.category!]
+  const normalizedConfiguredFallbackModels = normalizeFallbackModels(resolved.config.fallback_models)
  let actualModel: string | undefined
  let modelInfo: ModelFallbackInfo | undefined
  let categoryModel: { providerID: string; modelID: string; variant?: string } | undefined
@@ -99,6 +102,7 @@ Available categories: ${allCategoryNames}`,
  } else {
    const resolution = resolveModelForDelegateTask({
      userModel: explicitCategoryModel ?? overrideModel,
+      userFallbackModels: normalizedConfiguredFallbackModels,
      categoryDefaultModel: resolved.model,
      fallbackChain: requirement.fallbackChain,
      availableModels,
@@ -178,6 +182,14 @@ Available categories: ${categoryNames.join(", ")}`,
  const categoryConfigModel = resolved.config.model?.toLowerCase()
  const isUnstableAgent = resolved.config.is_unstable_agent === true || [unstableModel, categoryConfigModel].some(m => m ? m.includes("gemini") || m.includes("minimax") || m.includes("kimi") : false)

+  const defaultProviderID = categoryModel?.providerID
+    ?? parseModelString(actualModel ?? "")?.providerID
+    ?? "opencode"
+  const configuredFallbackChain = buildFallbackChainFromModels(
+    normalizedConfiguredFallbackModels,
+    defaultProviderID,
+  )
+
  return {
    agentToUse: SISYPHUS_JUNIOR_AGENT,
    categoryModel,
@@ -186,6 +198,6 @@ Available categories: ${categoryNames.join(", ")}`,
    modelInfo,
    actualModel,
    isUnstableAgent,
-    fallbackChain: requirement?.fallbackChain,
+    fallbackChain: configuredFallbackChain ?? requirement?.fallbackChain,
  }
 }
--- a/src/tools/delegate-task/model-selection.ts
+++ b/src/tools/delegate-task/model-selection.ts
@@ -14,6 +14,7 @@ function getExplicitHighBaseModel(model: string): string | null {

 export function resolveModelForDelegateTask(input: {
  userModel?: string
+  userFallbackModels?: string[]
  categoryDefaultModel?: string
  fallbackChain?: FallbackEntry[]
  availableModels: Set<string>
@@ -44,6 +45,28 @@ export function resolveModelForDelegateTask(input: {
    }
  }

+  const userFallbackModels = input.userFallbackModels
+  if (userFallbackModels && userFallbackModels.length > 0) {
+    if (input.availableModels.size === 0) {
+      const first = normalizeModel(userFallbackModels[0])
+      if (first) {
+        return { model: first }
+      }
+    } else {
+      for (const fallbackModel of userFallbackModels) {
+        const normalizedFallback = normalizeModel(fallbackModel)
+        if (!normalizedFallback) continue
+
+        const parts = normalizedFallback.split("/")
+        const providerHint = parts.length >= 2 ? [parts[0]] : undefined
+        const match = fuzzyMatchModel(normalizedFallback, input.availableModels, providerHint)
+        if (match) {
+          return { model: match }
+        }
+      }
+    }
+  }
+
  const fallbackChain = input.fallbackChain
  if (fallbackChain && fallbackChain.length > 0) {
    if (input.availableModels.size === 0) {
--- a/src/tools/delegate-task/subagent-resolver.test.ts
+++ b/src/tools/delegate-task/subagent-resolver.test.ts
@@ -17,7 +17,10 @@ function createBaseArgs(overrides?: Partial<DelegateTaskArgs>): DelegateTaskArgs
  }
 }

-function createExecutorContext(agentsFn: () => Promise<unknown>): ExecutorContext {
+function createExecutorContext(
+  agentsFn: () => Promise<unknown>,
+  overrides?: Partial<ExecutorContext>,
+): ExecutorContext {
  const client = {
    app: {
      agents: agentsFn,
@@ -28,6 +31,7 @@ function createExecutorContext(agentsFn: () => Promise<unknown>): ExecutorContex
    client,
    manager: {} as ExecutorContext["manager"],
    directory: "/tmp/test",
+    ...overrides,
  }
 }

@@ -101,4 +105,74 @@ describe("resolveSubagentExecution", () => {
    expect(result.categoryModel).toEqual({ providerID: "openai", modelID: "gpt-5.3-codex" })
    cacheSpy.mockRestore()
  })
+
+  test("uses agent override fallback_models for subagent runtime fallback chain", async () => {
+    //#given
+    const cacheSpy = spyOn(connectedProvidersCache, "readProviderModelsCache").mockReturnValue({
+      models: { quotio: ["claude-haiku-4-5"] },
+      connected: ["quotio"],
+      updatedAt: "2026-03-03T00:00:00.000Z",
+    })
+    const args = createBaseArgs({ subagent_type: "explore" })
+    const executorCtx = createExecutorContext(
+      async () => ([
+        { name: "explore", mode: "subagent", model: "quotio/claude-haiku-4-5" },
+      ]),
+      {
+        agentOverrides: {
+          explore: {
+            fallback_models: ["quotio/gpt-5.2", "glm-5(max)"],
+          },
+        } as ExecutorContext["agentOverrides"],
+      }
+    )
+
+    //#when
+    const result = await resolveSubagentExecution(args, executorCtx, "sisyphus", "deep")
+
+    //#then
+    expect(result.error).toBeUndefined()
+    expect(result.fallbackChain).toEqual([
+      { providers: ["quotio"], model: "gpt-5.2", variant: undefined },
+      { providers: ["quotio"], model: "glm-5", variant: "max" },
+    ])
+    cacheSpy.mockRestore()
+  })
+
+  test("uses category fallback_models when agent override points at category", async () => {
+    //#given
+    const cacheSpy = spyOn(connectedProvidersCache, "readProviderModelsCache").mockReturnValue({
+      models: { anthropic: ["claude-haiku-4-5"] },
+      connected: ["anthropic"],
+      updatedAt: "2026-03-03T00:00:00.000Z",
+    })
+    const args = createBaseArgs({ subagent_type: "explore" })
+    const executorCtx = createExecutorContext(
+      async () => ([
+        { name: "explore", mode: "subagent", model: "quotio/claude-haiku-4-5" },
+      ]),
+      {
+        agentOverrides: {
+          explore: {
+            category: "research",
+          },
+        } as ExecutorContext["agentOverrides"],
+        userCategories: {
+          research: {
+            fallback_models: ["anthropic/claude-haiku-4-5"],
+          },
+        } as ExecutorContext["userCategories"],
+      }
+    )
+
+    //#when
+    const result = await resolveSubagentExecution(args, executorCtx, "sisyphus", "deep")
+
+    //#then
+    expect(result.error).toBeUndefined()
+    expect(result.fallbackChain).toEqual([
+      { providers: ["anthropic"], model: "claude-haiku-4-5", variant: undefined },
+    ])
+    cacheSpy.mockRestore()
+  })
 })
--- a/src/tools/delegate-task/subagent-resolver.ts
+++ b/src/tools/delegate-task/subagent-resolver.ts
@@ -4,6 +4,8 @@ import { isPlanFamily } from "./constants"
 import { SISYPHUS_JUNIOR_AGENT } from "./sisyphus-junior-agent"
 import { normalizeModelFormat } from "../../shared/model-format-normalizer"
 import { AGENT_MODEL_REQUIREMENTS } from "../../shared/model-requirements"
+import { normalizeFallbackModels } from "../../shared/model-resolver"
+import { buildFallbackChainFromModels } from "../../shared/fallback-chain-from-models"
 import { getAgentDisplayName, getAgentConfigKey } from "../../shared/agent-display-names"
 import { normalizeSDKResponse } from "../../shared"
 import { log } from "../../shared/logger"
@@ -17,7 +19,7 @@ export async function resolveSubagentExecution(
  parentAgent: string | undefined,
  categoryExamples: string
 ): Promise<{ agentToUse: string; categoryModel: { providerID: string; modelID: string; variant?: string } | undefined; fallbackChain?: FallbackEntry[]; error?: string }> {
-  const { client, agentOverrides } = executorCtx
+  const { client, agentOverrides, userCategories } = executorCtx

  if (!args.subagent_type?.trim()) {
    return { agentToUse: "", categoryModel: undefined, error: `Agent name cannot be empty.` }
@@ -98,7 +100,10 @@ Create the work plan directly - that's your job as the planning agent.`,
    const agentOverride = agentOverrides?.[agentConfigKey as keyof typeof agentOverrides]
      ?? (agentOverrides ? Object.entries(agentOverrides).find(([key]) => key.toLowerCase() === agentConfigKey)?.[1] : undefined)
    const agentRequirement = AGENT_MODEL_REQUIREMENTS[agentConfigKey]
-    fallbackChain = agentRequirement?.fallbackChain
+    const normalizedAgentFallbackModels = normalizeFallbackModels(
+      agentOverride?.fallback_models
+      ?? (agentOverride?.category ? userCategories?.[agentOverride.category]?.fallback_models : undefined)
+    )

    if (agentOverride?.model || agentRequirement || matchedAgent.model) {
      const availableModels = await getAvailableModelsForDelegateTask(client)
@@ -112,6 +117,7 @@ Create the work plan directly - that's your job as the planning agent.`,

      const resolution = resolveModelForDelegateTask({
        userModel: agentOverride?.model,
+        userFallbackModels: normalizedAgentFallbackModels,
        categoryDefaultModel: matchedAgentModelStr,
        fallbackChain: agentRequirement?.fallbackChain,
        availableModels,
@@ -125,6 +131,15 @@ Create the work plan directly - that's your job as the planning agent.`,
          categoryModel = variantToUse ? { ...normalized, variant: variantToUse } : normalized
        }
      }
+
+      const defaultProviderID = categoryModel?.providerID
+        ?? normalizedMatchedModel?.providerID
+        ?? "opencode"
+      const configuredFallbackChain = buildFallbackChainFromModels(
+        normalizedAgentFallbackModels,
+        defaultProviderID,
+      )
+      fallbackChain = configuredFallbackChain ?? agentRequirement?.fallbackChain
    }

    if (!categoryModel && matchedAgent.model) {