fix(session-recovery): handle unavailable_tool (dummy_tool) errors

src/hooks/anthropic-context-window-limit-recovery/recovery-hook.test.ts

@@ -1,4 +1,4 @@
-import { afterAll, beforeEach, describe, expect, mock, test } from "bun:test"
+import { afterAll, afterEach, beforeEach, describe, expect, mock, test } from "bun:test"
 import type { PluginInput } from "@opencode-ai/plugin"
 import * as originalExecutor from "./executor"
 import * as originalParser from "./parser"
@@ -81,6 +81,10 @@ describe("createAnthropicContextWindowLimitRecoveryHook", () => {
     parseAnthropicTokenLimitErrorMock.mockClear()
   })
 
+  afterEach(() => {
+    mock.restore()
+  })
+
   test("cancels pending timer when session.idle handles compaction first", async () => {
     //#given
     const { restore, getClearTimeoutCalls } = setupDelayedTimeoutMocks()

src/hooks/session-recovery/detect-error-type.test.ts

@@ -1,6 +1,6 @@
 /// <reference types="bun-types" />
 import { describe, expect, it } from "bun:test"
-import { detectErrorType, extractMessageIndex } from "./detect-error-type"
+import { detectErrorType, extractMessageIndex, extractUnavailableToolName } from "./detect-error-type"
 
 describe("detectErrorType", () => {
   it("#given a tool_use/tool_result error #when detecting #then returns tool_result_missing", () => {
@@ -101,6 +101,56 @@ describe("detectErrorType", () => {
     //#then
     expect(result).toBe("tool_result_missing")
   })
+
+  it("#given a dummy_tool unavailable tool error #when detecting #then returns unavailable_tool", () => {
+    //#given
+    const error = { message: "model tried to call unavailable tool 'invalid'" }
+
+    //#when
+    const result = detectErrorType(error)
+
+    //#then
+    expect(result).toBe("unavailable_tool")
+  })
+
+  it("#given a no such tool error #when detecting #then returns unavailable_tool", () => {
+    //#given
+    const error = { message: "No such tool: grepppp" }
+
+    //#when
+    const result = detectErrorType(error)
+
+    //#then
+    expect(result).toBe("unavailable_tool")
+  })
+
+  it("#given a NoSuchToolError token #when detecting #then returns unavailable_tool", () => {
+    //#given
+    const error = { message: "NoSuchToolError: no such tool invalid" }
+
+    //#when
+    const result = detectErrorType(error)
+
+    //#then
+    expect(result).toBe("unavailable_tool")
+  })
+
+  it("#given a dummy_tool token in nested error #when detecting #then returns unavailable_tool", () => {
+    //#given
+    const error = {
+      data: {
+        error: {
+          message: "dummy_tool Model tried to call unavailable tool 'invalid'",
+        },
+      },
+    }
+
+    //#when
+    const result = detectErrorType(error)
+
+    //#then
+    expect(result).toBe("unavailable_tool")
+  })
 })
 
 describe("extractMessageIndex", () => {
@@ -127,3 +177,38 @@ describe("extractMessageIndex", () => {
     expect(result).toBeNull()
   })
 })
+
+describe("extractUnavailableToolName", () => {
+  it("#given unavailable tool error with quoted tool name #when extracting #then returns tool name", () => {
+    //#given
+    const error = { message: "model tried to call unavailable tool 'invalid'" }
+
+    //#when
+    const result = extractUnavailableToolName(error)
+
+    //#then
+    expect(result).toBe("invalid")
+  })
+
+  it("#given error without unavailable tool name #when extracting #then returns null", () => {
+    //#given
+    const error = { message: "dummy_tool appeared without tool name" }
+
+    //#when
+    const result = extractUnavailableToolName(error)
+
+    //#then
+    expect(result).toBeNull()
+  })
+
+  it("#given no such tool error with colon format #when extracting #then returns tool name", () => {
+    //#given
+    const error = { message: "No such tool: invalid_tool" }
+
+    //#when
+    const result = extractUnavailableToolName(error)
+
+    //#then
+    expect(result).toBe("invalid_tool")
+  })
+})

src/hooks/session-recovery/detect-error-type.ts

@@ -3,6 +3,7 @@ export type RecoveryErrorType =
   | "thinking_block_order"
   | "thinking_disabled_violation"
   | "assistant_prefill_unsupported"
+  | "unavailable_tool"
   | null
 
 function getErrorMessage(error: unknown): string {
@@ -43,6 +44,16 @@ export function extractMessageIndex(error: unknown): number | null {
   }
 }
 
+export function extractUnavailableToolName(error: unknown): string | null {
+  try {
+    const message = getErrorMessage(error)
+    const match = message.match(/(?:unavailable tool|no such tool)[:\s'"]+([^'".\s]+)/)
+    return match ? match[1] : null
+  } catch {
+    return null
+  }
+}
+
 export function detectErrorType(error: unknown): RecoveryErrorType {
   try {
     const message = getErrorMessage(error)
@@ -74,6 +85,16 @@ export function detectErrorType(error: unknown): RecoveryErrorType {
       return "tool_result_missing"
     }
 
+    if (
+      message.includes("dummy_tool") ||
+      message.includes("unavailable tool") ||
+      message.includes("model tried to call unavailable") ||
+      message.includes("nosuchtoolerror") ||
+      message.includes("no such tool")
+    ) {
+      return "unavailable_tool"
+    }
+
     return null
   } catch {
     return null

src/hooks/session-recovery/hook.ts

@@ -5,6 +5,7 @@ import { detectErrorType } from "./detect-error-type"
 import type { RecoveryErrorType } from "./detect-error-type"
 import type { MessageData } from "./types"
 import { recoverToolResultMissing } from "./recover-tool-result-missing"
+import { recoverUnavailableTool } from "./recover-unavailable-tool"
 import { recoverThinkingBlockOrder } from "./recover-thinking-block-order"
 import { recoverThinkingDisabledViolation } from "./recover-thinking-disabled-violation"
 import { extractResumeConfig, findLastUserMessage, resumeSession } from "./resume"
@@ -79,12 +80,14 @@ export function createSessionRecoveryHook(ctx: PluginInput, options?: SessionRec
 
       const toastTitles: Record<RecoveryErrorType & string, string> = {
         tool_result_missing: "Tool Crash Recovery",
+        unavailable_tool: "Tool Recovery",
         thinking_block_order: "Thinking Block Recovery",
         thinking_disabled_violation: "Thinking Strip Recovery",
         "assistant_prefill_unsupported": "Prefill Unsupported",
       }
       const toastMessages: Record<RecoveryErrorType & string, string> = {
         tool_result_missing: "Injecting cancelled tool results...",
+        unavailable_tool: "Recovering from unavailable tool call...",
         thinking_block_order: "Fixing message structure...",
         thinking_disabled_violation: "Stripping thinking blocks...",
         "assistant_prefill_unsupported": "Prefill not supported; continuing without recovery.",
@@ -105,6 +108,8 @@ export function createSessionRecoveryHook(ctx: PluginInput, options?: SessionRec
 
       if (errorType === "tool_result_missing") {
         success = await recoverToolResultMissing(ctx.client, sessionID, failedMsg)
+      } else if (errorType === "unavailable_tool") {
+        success = await recoverUnavailableTool(ctx.client, sessionID, failedMsg)
       } else if (errorType === "thinking_block_order") {
         success = await recoverThinkingBlockOrder(ctx.client, sessionID, failedMsg, ctx.directory, info.error)
         if (success && experimental?.auto_resume) {

src/hooks/session-recovery/recover-unavailable-tool.ts

@@ -0,0 +1,108 @@
+import type { createOpencodeClient } from "@opencode-ai/sdk"
+import { extractUnavailableToolName } from "./detect-error-type"
+import { readParts } from "./storage"
+import type { MessageData } from "./types"
+import { normalizeSDKResponse } from "../../shared"
+import { isSqliteBackend } from "../../shared/opencode-storage-detection"
+
+type Client = ReturnType<typeof createOpencodeClient>
+
+interface ToolResultPart {
+  type: "tool_result"
+  tool_use_id: string
+  content: string
+}
+
+interface PromptWithToolResultInput {
+  path: { id: string }
+  body: { parts: ToolResultPart[] }
+}
+
+interface ToolUsePart {
+  type: "tool_use"
+  id: string
+  name: string
+}
+
+interface MessagePart {
+  type: string
+  id?: string
+  name?: string
+}
+
+function extractToolUseParts(parts: MessagePart[]): ToolUsePart[] {
+  return parts.filter(
+    (part): part is ToolUsePart =>
+      part.type === "tool_use" && typeof part.id === "string" && typeof part.name === "string"
+  )
+}
+
+async function readPartsFromSDKFallback(
+  client: Client,
+  sessionID: string,
+  messageID: string
+): Promise<MessagePart[]> {
+  try {
+    const response = await client.session.messages({ path: { id: sessionID } })
+    const messages = normalizeSDKResponse(response, [] as MessageData[], { preferResponseOnMissingData: true })
+    const target = messages.find((message) => message.info?.id === messageID)
+    if (!target?.parts) return []
+
+    return target.parts.map((part) => ({
+      type: part.type === "tool" ? "tool_use" : part.type,
+      id: "callID" in part ? (part as { callID?: string }).callID : part.id,
+      name: "name" in part && typeof part.name === "string" ? part.name : ("tool" in part && typeof (part as { tool?: unknown }).tool === "string" ? (part as { tool: string }).tool : undefined),
+    }))
+  } catch {
+    return []
+  }
+}
+
+export async function recoverUnavailableTool(
+  client: Client,
+  sessionID: string,
+  failedAssistantMsg: MessageData
+): Promise<boolean> {
+  let parts = failedAssistantMsg.parts || []
+  if (parts.length === 0 && failedAssistantMsg.info?.id) {
+    if (isSqliteBackend()) {
+      parts = await readPartsFromSDKFallback(client, sessionID, failedAssistantMsg.info.id)
+    } else {
+      const storedParts = readParts(failedAssistantMsg.info.id)
+      parts = storedParts.map((part) => ({
+        type: part.type === "tool" ? "tool_use" : part.type,
+        id: "callID" in part ? (part as { callID?: string }).callID : part.id,
+        name: "tool" in part && typeof part.tool === "string" ? part.tool : undefined,
+      }))
+    }
+  }
+
+  const toolUseParts = extractToolUseParts(parts)
+  if (toolUseParts.length === 0) {
+    return false
+  }
+
+  const unavailableToolName = extractUnavailableToolName(failedAssistantMsg.info?.error)
+  const matchingToolUses = unavailableToolName
+    ? toolUseParts.filter((part) => part.name.toLowerCase() === unavailableToolName)
+    : []
+  const targetToolUses = matchingToolUses.length > 0 ? matchingToolUses : toolUseParts
+
+  const toolResultParts = targetToolUses.map((part) => ({
+    type: "tool_result" as const,
+    tool_use_id: part.id,
+    content: '{"status":"error","error":"Tool not available. Please continue without this tool."}',
+  }))
+
+  try {
+    const promptInput: PromptWithToolResultInput = {
+      path: { id: sessionID },
+      body: { parts: toolResultParts },
+    }
+    const promptAsync = client.session.promptAsync as (...args: never[]) => unknown
+    await Reflect.apply(promptAsync, client.session, [promptInput])
+    return true
+  } catch {
+    return false
+  }
+}

src/plugin-handlers/agent-config-handler.ts

@@ -82,7 +82,7 @@ export async function applyAgentConfig(params: {
     migratedDisabledAgents,
     params.pluginConfig.agents,
     params.ctx.directory,
-    undefined,
+    currentModel,
     params.pluginConfig.categories,
     params.pluginConfig.git_master,
     allDiscoveredSkills,

src/plugin-handlers/config-handler.test.ts

@@ -1277,12 +1277,15 @@ describe("per-agent todowrite/todoread deny when task_system enabled", () => {
 })
 
 describe("disable_omo_env pass-through", () => {
-  test("omits <omo-env> in generated sisyphus prompt when disable_omo_env is true", async () => {
+  test("passes disable_omo_env=true to createBuiltinAgents", async () => {
     //#given
-    ;(agents.createBuiltinAgents as any)?.mockRestore?.()
-    ;(shared.fetchAvailableModels as any).mockResolvedValue(
-      new Set(["anthropic/claude-opus-4-6", "google/gemini-3-flash"])
-    )
+    const createBuiltinAgentsMock = agents.createBuiltinAgents as unknown as {
+      mockResolvedValue: (value: Record<string, unknown>) => void
+      mock: { calls: unknown[][] }
+    }
+    createBuiltinAgentsMock.mockResolvedValue({
+      sisyphus: { name: "sisyphus", prompt: "without-env", mode: "primary" },
+    })
 
     const pluginConfig: OhMyOpenCodeConfig = {
       experimental: { disable_omo_env: true },
@@ -1304,18 +1307,21 @@ describe("disable_omo_env pass-through", () => {
     await handler(config)
 
     //#then
-    const agentResult = config.agent as Record<string, { prompt?: string }>
-    const sisyphusPrompt = agentResult[getAgentDisplayName("sisyphus")]?.prompt
-    expect(sisyphusPrompt).toBeDefined()
-    expect(sisyphusPrompt).not.toContain("<omo-env>")
+    const lastCall =
+      createBuiltinAgentsMock.mock.calls[createBuiltinAgentsMock.mock.calls.length - 1]
+    expect(lastCall).toBeDefined()
+    expect(lastCall?.[12]).toBe(true)
   })
 
-  test("keeps <omo-env> in generated sisyphus prompt when disable_omo_env is omitted", async () => {
+  test("passes disable_omo_env=false to createBuiltinAgents when omitted", async () => {
     //#given
-    ;(agents.createBuiltinAgents as any)?.mockRestore?.()
-    ;(shared.fetchAvailableModels as any).mockResolvedValue(
-      new Set(["anthropic/claude-opus-4-6", "google/gemini-3-flash"])
-    )
+    const createBuiltinAgentsMock = agents.createBuiltinAgents as unknown as {
+      mockResolvedValue: (value: Record<string, unknown>) => void
+      mock: { calls: unknown[][] }
+    }
+    createBuiltinAgentsMock.mockResolvedValue({
+      sisyphus: { name: "sisyphus", prompt: "with-env", mode: "primary" },
+    })
 
     const pluginConfig: OhMyOpenCodeConfig = {}
     const config: Record<string, unknown> = {
@@ -1335,9 +1341,9 @@ describe("disable_omo_env pass-through", () => {
     await handler(config)
 
     //#then
-    const agentResult = config.agent as Record<string, { prompt?: string }>
-    const sisyphusPrompt = agentResult[getAgentDisplayName("sisyphus")]?.prompt
-    expect(sisyphusPrompt).toBeDefined()
-    expect(sisyphusPrompt).toContain("<omo-env>")
+    const lastCall =
+      createBuiltinAgentsMock.mock.calls[createBuiltinAgentsMock.mock.calls.length - 1]
+    expect(lastCall).toBeDefined()
+    expect(lastCall?.[12]).toBe(false)
   })
 })

src/plugin/chat-headers.test.ts

@@ -66,7 +66,7 @@ describe("createChatHeadersHandler", () => {
         sessionID: "ses_1",
         provider: { id: "openai" },
         message: {
-          id: "msg_1",
+          id: "msg_2",
           role: "user",
         },
       },