fix(tool-pair-validator): emit schema-compatible synthetic tool results

src/hooks/session-recovery/recover-tool-result-missing.test.ts

@@ -82,8 +82,10 @@ describe("recoverToolResultMissing", () => {
       body: {
         parts: [{
           type: "tool_result",
+          toolUseId: "call_recovered",
           tool_use_id: "call_recovered",
-          content: "Operation cancelled by user (ESC pressed)",
+          isError: true,
+          content: [{ type: "text", text: "Operation cancelled by user (ESC pressed)" }],
         }],
       },
     })
@@ -123,8 +125,10 @@ describe("recoverToolResultMissing", () => {
       body: {
         parts: [{
           type: "tool_result",
+          toolUseId: "toolu_recovered",
           tool_use_id: "toolu_recovered",
-          content: "Operation cancelled by user (ESC pressed)",
+          isError: true,
+          content: [{ type: "text", text: "Operation cancelled by user (ESC pressed)" }],
         }],
       },
     })

src/hooks/session-recovery/recover-tool-result-missing.ts

@@ -6,6 +6,14 @@ import { normalizeSDKResponse } from "../../shared"
 import { promptAsyncAfterSessionIdle } from "../shared/prompt-async-gate"
 
 type Client = ReturnType<typeof createOpencodeClient>
+type ToolResultContent = { type: "text"; text: string }
+type ToolResultPart = {
+  type: "tool_result"
+  toolUseId: string
+  tool_use_id?: string
+  isError?: boolean
+  content: ToolResultContent[]
+}
 type ClientWithPromptAsync = {
   session: {
     promptAsync: (opts: { path: { id: string }; body: Record<string, unknown> }) => Promise<unknown>
@@ -96,8 +104,10 @@ export async function recoverToolResultMissing(
 
   const toolResultParts = toolUseIds.map((id) => ({
     type: "tool_result" as const,
+    toolUseId: id,
     tool_use_id: id,
-    content: "Operation cancelled by user (ESC pressed)",
+    isError: true,
+    content: [{ type: "text" as const, text: "Operation cancelled by user (ESC pressed)" }],
   }))
 
   const launchAgent = resumeConfig?.agent

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

@@ -0,0 +1,105 @@
+import { afterEach, beforeEach, describe, expect, it, mock } from "bun:test"
+
+import type { MessageData } from "./types"
+
+let sqliteBackend = false
+let storedParts: Array<{ type: string; id?: string; callID?: string; name?: string; tool?: string; [key: string]: unknown }> = []
+
+mock.module("../../shared/opencode-storage-detection", () => ({
+  isSqliteBackend: () => sqliteBackend,
+}))
+
+mock.module("./storage", () => ({
+  readParts: () => storedParts,
+}))
+
+const { recoverUnavailableTool } = await import("./recover-unavailable-tool")
+
+const failedAssistantMsg: MessageData = {
+  info: { id: "msg_failed", role: "assistant", error: 'No such tool: bash' },
+  parts: [],
+}
+
+function createMockClient(messages: MessageData[] = []) {
+  const promptAsync = mock(() => Promise.resolve({}))
+
+  return {
+    client: {
+      session: {
+        messages: mock(() => Promise.resolve({ data: messages })),
+        promptAsync,
+      },
+    } as never,
+    promptAsync,
+  }
+}
+
+describe("recoverUnavailableTool", () => {
+  beforeEach(() => {
+    sqliteBackend = false
+    storedParts = []
+  })
+
+  afterEach(() => {
+    mock.restore()
+  })
+
+  it("sends a schema-compatible recovered tool result for sqlite fallback", async () => {
+    //#given
+    sqliteBackend = true
+    const { client, promptAsync } = createMockClient([
+      {
+        info: { id: "msg_failed", role: "assistant" },
+        parts: [{ type: "tool", id: "prt_valid_call", callID: "call_recovered", name: "bash", input: {} }],
+      },
+    ])
+
+    //#when
+    const result = await recoverUnavailableTool(client, "ses_1", failedAssistantMsg)
+
+    //#then
+    expect(result).toBe(true)
+    expect(promptAsync).toHaveBeenCalledWith({
+      path: { id: "ses_1" },
+      body: {
+        parts: [{
+          type: "tool_result",
+          toolUseId: "call_recovered",
+          tool_use_id: "call_recovered",
+          isError: true,
+          content: [{ type: "text", text: '{"status":"error","error":"Tool not available. Please continue without this tool."}' }],
+        }],
+      },
+    })
+  })
+
+  it("sends a schema-compatible recovered tool result for stored parts fallback", async () => {
+    //#given
+    storedParts = [{
+      type: "tool",
+      id: "prt_stored_valid_call",
+      callID: "toolu_recovered",
+      tool: "bash",
+      state: { input: {} },
+    }]
+    const { client, promptAsync } = createMockClient()
+
+    //#when
+    const result = await recoverUnavailableTool(client, "ses_2", failedAssistantMsg)
+
+    //#then
+    expect(result).toBe(true)
+    expect(promptAsync).toHaveBeenCalledWith({
+      path: { id: "ses_2" },
+      body: {
+        parts: [{
+          type: "tool_result",
+          toolUseId: "toolu_recovered",
+          tool_use_id: "toolu_recovered",
+          isError: true,
+          content: [{ type: "text", text: '{"status":"error","error":"Tool not available. Please continue without this tool."}' }],
+        }],
+      },
+    })
+  })
+})

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

@@ -10,8 +10,10 @@ type Client = ReturnType<typeof createOpencodeClient>
 
 interface ToolResultPart {
   type: "tool_result"
-  tool_use_id: string
-  content: string
+  toolUseId: string
+  tool_use_id?: string
+  isError?: boolean
+  content: Array<{ type: "text"; text: string }>
 }
 
 interface PromptWithToolResultInput {
@@ -91,8 +93,10 @@ export async function recoverUnavailableTool(
 
   const toolResultParts = targetToolUses.map((part) => ({
     type: "tool_result" as const,
+    toolUseId: part.id,
     tool_use_id: part.id,
-    content: '{"status":"error","error":"Tool not available. Please continue without this tool."}',
+    isError: true,
+    content: [{ type: "text" as const, text: '{"status":"error","error":"Tool not available. Please continue without this tool."}' }],
   }))
 
   try {