agentclientprotocol · benbrandt · Sep 14, 2026 · Sep 14, 2026
diff --git a/src/CodexEventHandler.ts b/src/CodexEventHandler.ts
@@ -63,6 +63,7 @@ import {
     fuzzyFileSearchToolCallId,
 } from "./CodexToolCallMapper";
 import { stripShellPrefix } from "./CommandUtils";
+import {commandToolName, functionToolName} from "./ToolCallName";
 import {createTerminalOutputMeta, type TerminalOutputMode} from "./TerminalOutputMode";
 import {
     createCodexMessagePhaseMeta,
@@ -765,10 +766,16 @@ export class CodexEventHandler {
     private async completeItemEvent(event: ItemCompletedNotification): Promise<UpdateSessionEvent | null> {
         switch (event.item.type) {
             case "fileChange":
+                return {
+                    sessionUpdate: "tool_call_update",
+                    toolCallId: event.item.id,
+                    status: event.item.status === "completed" ? "completed" : "failed",
+                }
             case "dynamicToolCall":
                 return {
                     sessionUpdate: "tool_call_update",
                     toolCallId: event.item.id,
+                    name: functionToolName(event.item.tool, event.item.namespace),
                     status: event.item.status === "completed" ? "completed" : "failed",
                 }
             case "mcpToolCall":
@@ -1006,9 +1013,11 @@ export class CodexEventHandler {
     }
 
     private completeCommandExecutionEvent(item: ThreadItem & { "type": "commandExecution" }): UpdateSessionEvent {
+        const name = commandToolName(item.source);
         const update: UpdateSessionEvent = {
             sessionUpdate: "tool_call_update",
             toolCallId: item.id,
+            ...(name === undefined ? {} : {name}),
             status: item.status === "completed" ? "completed" : "failed",
             rawOutput: {
                 formatted_output: item.aggregatedOutput ?? "",

diff --git a/src/CodexToolCallMapper.ts b/src/CodexToolCallMapper.ts
@@ -33,6 +33,7 @@ import {
     type TerminalOutputMode,
 } from "./TerminalOutputMode";
 import {createContextCompactionMeta} from "./ContextCompactionMeta";
+import {commandToolName, functionToolName} from "./ToolCallName";
 
 type CodexItemStatus = CommandExecutionStatus | PatchApplyStatus | McpToolCallStatus | DynamicToolCallStatus | CollabAgentToolCallStatus;
 type AcpToolCallStatus = "pending" | "in_progress" | "completed" | "failed";
@@ -81,14 +82,19 @@ export async function createFileChangeUpdate(
 }
 
 export async function createCommandExecutionUpdate(item: CommandExecutionItem): Promise<UpdateSessionEvent> {
+    const name = commandToolName(item.source);
     const commandAction = item.commandActions.length === 1 ? item.commandActions[0] : undefined;
     if (commandAction) {
-        return createCommandActionEvent(item.id, item.status, item.cwd, commandAction);
+        return {
+            ...createCommandActionEvent(item.id, item.status, item.cwd, commandAction),
+            ...(name === undefined ? {} : {name}),
+        };
     }
     const command = stripShellPrefix(item.command);
     return createTerminalCommandEvent({
         sessionUpdate: "tool_call",
         toolCallId: item.id,
+        ...(name === undefined ? {} : {name}),
         kind: "execute",
         title: command,
         status: toAcpStatus(item.status),
@@ -157,7 +163,10 @@ export async function createMcpToolCallUpdate(
 export async function createDynamicToolCallUpdate(
     item: ThreadItem & { type: "dynamicToolCall" }
 ): Promise<UpdateSessionEvent> {
-    return createExecuteToolCallUpdate(item, item.tool, { arguments: item.arguments })
+    return {
+        ...await createExecuteToolCallUpdate(item, item.tool, { arguments: item.arguments }),
+        name: functionToolName(item.tool, item.namespace),
+    };
 }
 
 export function createImageViewUpdate(
@@ -168,6 +177,7 @@ export function createImageViewUpdate(
         sessionUpdate: "tool_call",
         toolCallId: item.id,
         kind: "read",
+        name: "view_image",
         title: `View Image ${displayPath}`,
         status: "completed",
         content: [createContent({
@@ -269,7 +279,7 @@ export async function createExecuteToolCallUpdate(
     title: string,
     rawInput?: Record<string, JsonValue | string>,
     rawOutput?: Record<string, JsonValue | string | null>,
-): Promise<UpdateSessionEvent> {
+): Promise<AcpToolCallEvent> {
     return {
         sessionUpdate: "tool_call",
         toolCallId: item.id,

diff --git a/src/ResponseItemHistoryFallback.ts b/src/ResponseItemHistoryFallback.ts
@@ -7,6 +7,7 @@ import type { CommandAction, Thread, ThreadItem } from "./app-server/v2";
 import { createCommandActionEvent } from "./CodexToolCallMapper";
 import { createTerminalOutputMeta, type TerminalOutputMode } from "./TerminalOutputMode";
 import { createAgentMessageChunk, createCodexMessagePhaseMeta } from "./ContentChunks";
+import { functionToolName } from "./ToolCallName";
 
 type JsonRecord = Record<string, unknown>;
 type AcpToolCallEvent = Extract<UpdateSessionEvent, { sessionUpdate: "tool_call" }>;
@@ -368,6 +369,7 @@ function createFunctionCallUpdate(item: JsonRecord): LegacyFunctionCallUpdate |
     if (!toolCallId || !name) {
         return null;
     }
+    const toolName = functionToolName(name, stringValue(item["namespace"]));
 
     const isExecCommand = name === "exec_command";
     const args = parseFunctionArguments(item["arguments"]);
@@ -376,7 +378,10 @@ function createFunctionCallUpdate(item: JsonRecord): LegacyFunctionCallUpdate |
     const commandAction = command ? inferCommandAction(command, cwd) : null;
     if (commandAction) {
         return {
-            update: createCommandActionEvent(toolCallId, "inProgress", cwd, commandAction),
+            update: {
+                ...createCommandActionEvent(toolCallId, "inProgress", cwd, commandAction),
+                name: toolName,
+            },
             usesTerminal: false,
             isExecCommand,
         };
@@ -385,6 +390,7 @@ function createFunctionCallUpdate(item: JsonRecord): LegacyFunctionCallUpdate |
     const update: AcpToolCallEvent = {
         sessionUpdate: "tool_call",
         toolCallId,
+        name: toolName,
         kind: toolKindForFunctionCall(name),
         title: titleForFunctionCall(name, args),
         status: "in_progress",

diff --git a/src/ToolCallName.ts b/src/ToolCallName.ts
@@ -0,0 +1,19 @@
+import type {CommandExecutionSource} from "./app-server/v2";
+
+/** Matches Codex's flattened ToolName at boundaries that require a single string. */
+export function functionToolName(name: string, namespace?: string | null): string {
+    return `${namespace ?? ""}${name}`;
+}
+
+export function commandToolName(source: CommandExecutionSource): string | undefined {
+    switch (source) {
+        case "unifiedExecStartup":
+            return "exec_command";
+        case "unifiedExecInteraction":
+            return "write_stdin";
+        // These sources do not identify a unique model tool.
+        case "agent":
+        case "userShell":
+            return undefined;
+    }
+}
diff --git a/src/__tests__/CodexACPAgent/approval-events.test.ts b/src/__tests__/CodexACPAgent/approval-events.test.ts
@@ -90,6 +90,46 @@ describe("Approval Events", () => {
     }
 
     describe("command approvals", () => {
+        it.each([
+            ["unifiedExecStartup", "exec_command"],
+            ["unifiedExecInteraction", "write_stdin"],
+            ["agent", undefined],
+            ["userShell", undefined],
+        ] as const)("uses only a known tool name for %s command approvals", async (source, name) => {
+            const prompt = setupSessionWithPendingPrompt();
+            fixture.sendServerNotification({
+                method: "item/started",
+                params: {
+                    threadId: sessionId,
+                    turnId: "turn-1",
+                    startedAtMs: 0,
+                    item: {
+                        type: "commandExecution",
+                        id: "command-item",
+                        pluginId: null,
+                        scriptPath: null,
+                        command: "npm test",
+                        cwd: "/workspace",
+                        processId: null,
+                        source,
+                        status: "inProgress",
+                        commandActions: [],
+                        aggregatedOutput: null,
+                        exitCode: null,
+                        durationMs: null,
+                    },
+                },
+            });
+            await fixture.getCodexAcpClient().waitForSessionNotifications(sessionId);
+            fixture.clearAcpConnectionDump();
+            fixture.setPermissionResponse({outcome: {outcome: "selected", optionId: ApprovalOptionId.AllowOnce}});
+
+            await fixture.sendServerRequest("item/commandExecution/requestApproval", commandParams(["accept", "cancel"]));
+
+            expect(permissionRequest().toolCall.name).toBe(name);
+            await finish(prompt);
+        });
+
         it("emits an autonomous ACP v1 snapshot and maps explicit reject to decline", async () => {
             const prompt = setupSessionWithPendingPrompt();
             fixture.setPermissionResponse({outcome: {outcome: "selected", optionId: ApprovalOptionId.Decline}});
@@ -653,6 +693,7 @@ describe("Approval Events", () => {
                 expect(permissionRequest()).toMatchObject({
                     toolCall: {
                         toolCallId: "permissions-item",
+                        name: "request_permissions",
                         kind: "other",
                         status: "pending",
                         title: "Additional sandbox permissions",

diff --git a/src/__tests__/CodexACPAgent/data/dynamic-tool-completed.json b/src/__tests__/CodexACPAgent/data/dynamic-tool-completed.json
@@ -6,6 +6,7 @@
       "update": {
         "sessionUpdate": "tool_call_update",
         "toolCallId": "dyn-tool-123",
+        "name": "list_apps",
         "status": "completed"
       }
     }

diff --git a/src/__tests__/CodexACPAgent/data/dynamic-tool-in-progress.json b/src/__tests__/CodexACPAgent/data/dynamic-tool-in-progress.json
@@ -13,7 +13,8 @@
           "arguments": {
             "includeDisabled": false
           }
-        }
+        },
+        "name": "list_apps"
       }
     }
   ]

diff --git a/src/__tests__/CodexACPAgent/data/load-session-history.json b/src/__tests__/CodexACPAgent/data/load-session-history.json
@@ -325,7 +325,8 @@
           "arguments": {
             "includeDisabled": false
           }
-        }
+        },
+        "name": "list_apps"
       }
     }
   ]
@@ -339,6 +340,7 @@
         "sessionUpdate": "tool_call",
         "toolCallId": "item-image-view-1",
         "kind": "read",
+        "name": "view_image",
         "title": "View Image /test/project/input.png",
         "status": "completed",
         "content": [

diff --git a/src/__tests__/CodexACPAgent/data/load-session-response-item-history-fallback.json b/src/__tests__/CodexACPAgent/data/load-session-response-item-history-fallback.json
@@ -192,7 +192,8 @@
         "toolCallId": "call-rg",
         "status": "in_progress",
         "kind": "search",
-        "title": "Search for 'Service' in src"
+        "title": "Search for 'Service' in src",
+        "name": "exec_command"
       }
     }
   ]
@@ -223,7 +224,8 @@
         "toolCallId": "call-rg-failed",
         "status": "in_progress",
         "kind": "search",
-        "title": "Search for 'Missing' in src"
+        "title": "Search for 'Missing' in src",
+        "name": "exec_command"
       }
     }
   ]
@@ -259,7 +261,8 @@
           {
             "path": "/test/project/src/index.ts"
           }
-        ]
+        ],
+        "name": "exec_command"
       }
     }
   ]
@@ -290,7 +293,8 @@
         "toolCallId": "call-ls",
         "status": "in_progress",
         "kind": "read",
-        "title": "List files"
+        "title": "List files",
+        "name": "exec_command"
       }
     }
   ]

diff --git a/src/__tests__/CodexACPAgent/data/response-item-history-tool-names.json b/src/__tests__/CodexACPAgent/data/response-item-history-tool-names.json
@@ -0,0 +1,89 @@
+[
+  {
+    "sessionUpdate": "tool_call",
+    "toolCallId": "call-search",
+    "status": "in_progress",
+    "kind": "search",
+    "title": "Search for 'Needle' in src",
+    "name": "exec_command"
+  },
+  {
+    "sessionUpdate": "tool_call",
+    "toolCallId": "call-terminal",
+    "name": "exec_command",
+    "kind": "execute",
+    "title": "npm test",
+    "status": "in_progress",
+    "content": [
+      {
+        "type": "terminal",
+        "terminalId": "call-terminal"
+      }
+    ],
+    "rawInput": {
+      "command": "npm test",
+      "cwd": "/workspace",
+      "arguments": {
+        "cmd": "npm test",
+        "workdir": "/workspace",
+        "yield_time_ms": 1000
+      }
+    },
+    "_meta": {
+      "terminal_info": {
+        "cwd": "/workspace",
+        "terminal_id": "call-terminal"
+      }
+    }
+  },
+  {
+    "sessionUpdate": "tool_call",
+    "toolCallId": "call-patch",
+    "name": "apply_patch",
+    "kind": "edit",
+    "title": "Apply patch",
+    "status": "in_progress",
+    "rawInput": {
+      "name": "apply_patch",
+      "arguments": {
+        "patch": "*** Begin Patch\n*** End Patch"
+      }
+    }
+  },
+  {
+    "sessionUpdate": "tool_call",
+    "toolCallId": "call-mcp",
+    "name": "mcp__docs__find_page",
+    "kind": "other",
+    "title": "mcp__docs__find_page",
+    "status": "in_progress",
+    "rawInput": {
+      "name": "mcp__docs__find_page",
+      "arguments": {
+        "query": "Tool names"
+      }
+    }
+  },
+  {
+    "sessionUpdate": "tool_call",
+    "toolCallId": "call-namespaced",
+    "name": "functions.read_file",
+    "kind": "other",
+    "title": "read_file",
+    "status": "in_progress",
+    "rawInput": {
+      "name": "read_file",
+      "arguments": {
+        "path": "README.md"
+      }
+    }
+  },
+  {
+    "sessionUpdate": "tool_call_update",
+    "toolCallId": "call-search",
+    "status": "completed",
+    "rawOutput": {
+      "output": "Chunk ID: search\nProcess exited with code 0\nOutput:\nsrc/index.ts\n"
+    }
+  }
+]
-Original file line number
+Diff line change
@@ Expand Up / @@ -13,7 +13,8 @@ @@
               "arguments": {
                 "includeDisabled": false
               }
-            }
+            },
+            "name": "list_apps"
           }
         }
       ]
@@ Expand Down @@