diff --git a/src/cli.test.ts b/src/cli.test.ts
index a9c640a..625f68d 100644
--- a/src/cli.test.ts
+++ b/src/cli.test.ts
@@ -42,3 +42,37 @@ describe("CLI model validation", () => {
     assert.equal(isKnownModel("unknown"), false);
   });
 });
+
+describe("CLI --no-timeout flag", () => {
+  function parseTimeout(optsTimeout: string | false): number {
+    // Mirrors cli.ts logic: --no-timeout sets opts.timeout to false
+    return optsTimeout === false ? 0 : parseInt(optsTimeout as string, 10);
+  }
+
+  function validateTimeout(optsTimeout: string | false): string | null {
+    const timeout = parseTimeout(optsTimeout);
+    if (optsTimeout !== false && (Number.isNaN(timeout) || timeout < 10 || timeout > 1800)) {
+      return "Error: --timeout must be a number between 10 and 1800 seconds";
+    }
+    return null;
+  }
+
+  it("--no-timeout sets timeout to 0", () => {
+    assert.equal(parseTimeout(false), 0);
+  });
+
+  it("--no-timeout passes validation", () => {
+    assert.equal(validateTimeout(false), null);
+  });
+
+  it("normal timeout values still validate", () => {
+    assert.equal(validateTimeout("300"), null);
+    assert.equal(parseTimeout("300"), 300);
+  });
+
+  it("invalid timeout values are rejected", () => {
+    assert.notEqual(validateTimeout("5"), null);
+    assert.notEqual(validateTimeout("abc"), null);
+    assert.notEqual(validateTimeout("9999"), null);
+  });
+});
diff --git a/src/cli.ts b/src/cli.ts
index 11137e1..49337d8 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -37,6 +37,7 @@ program
     String(cfg.testTimeout),
   )
   .option("--timeout <seconds>", "Timeout per agent in seconds", String(cfg.timeout))
+  .option("--no-timeout", "Disable agent timeout entirely")
   .option("--model <model>", "Claude model to use", cfg.model)
   .option("-r, --runner <name>", "AI coding tool to use", cfg.runner)
   .option(
@@ -46,7 +47,7 @@ program
   )
   .option("--scoring <method>", "Scoring method: copeland (default) or weighted", "copeland")
   .option("--no-color", "Disable colored output")
-  .option("--output-format <format>", "Output format: text (default) or json", "text")
+  .option("--output-format <format>", "Output format: text (default), json, or diff", "text")
   .option("--verbose", "Show detailed output from each agent")
   .option("--whitespace-insensitive", "Ignore whitespace differences in convergence comparison")
   .option("--retry", "Re-run only failed/timed-out agents from the last run")
@@ -57,8 +58,9 @@ program
       process.exit(1);
     }
 
-    const timeout = parseInt(opts.timeout, 10);
-    if (Number.isNaN(timeout) || timeout < 10 || timeout > 1800) {
+    // --no-timeout: commander sets opts.timeout to false
+    const timeout = opts.timeout === false ? 0 : parseInt(opts.timeout, 10);
+    if (opts.timeout !== false && (Number.isNaN(timeout) || timeout < 10 || timeout > 1800)) {
       console.error("Error: --timeout must be a number between 10 and 1800 seconds");
       process.exit(1);
     }
@@ -80,7 +82,7 @@ program
       process.env.NO_COLOR = "1";
     }
 
-    const validFormats = ["text", "json"];
+    const validFormats = ["text", "json", "diff"];
     if (!validFormats.includes(opts.outputFormat)) {
       console.error(`Error: --output-format must be one of: ${validFormats.join(", ")}`);
       process.exit(1);
diff --git a/src/commands/run.ts b/src/commands/run.ts
index 2be4566..41a32d8 100644
--- a/src/commands/run.ts
+++ b/src/commands/run.ts
@@ -306,6 +306,9 @@ export async function retry(opts: RunOptions): Promise<void> {
   // Display results
   if (opts.outputFormat === "json") {
     console.log(JSON.stringify(result));
+  } else if (opts.outputFormat === "diff") {
+    const recAgent = result.agents.find((a) => a.id === result.recommended);
+    if (recAgent?.diff) process.stdout.write(recAgent.diff);
   } else {
     displayResults(result);
     displayApplyInstructions(result);
@@ -506,6 +509,9 @@ export async function run(opts: RunOptions): Promise<void> {
   // Display results
   if (opts.outputFormat === "json") {
     console.log(JSON.stringify(result));
+  } else if (opts.outputFormat === "diff") {
+    const recAgent = result.agents.find((a) => a.id === result.recommended);
+    if (recAgent?.diff) process.stdout.write(recAgent.diff);
   } else {
     displayResults(result);
     displayApplyInstructions(result);
diff --git a/src/runners/claude-code.test.ts b/src/runners/claude-code.test.ts
index 40c50c3..58bcc5a 100644
--- a/src/runners/claude-code.test.ts
+++ b/src/runners/claude-code.test.ts
@@ -30,4 +30,20 @@ describe("claude-code runner", () => {
       });
     }
   });
+
+  describe("timeout=0 skips timer", () => {
+    it("does not call setTimeout when timeout is 0", () => {
+      // Mirrors the runner logic: timer is only created when timeout > 0
+      const timeout = 0;
+      const timer = timeout > 0 ? setTimeout(() => {}, timeout * 1000) : null;
+      assert.equal(timer, null);
+    });
+
+    it("creates timer when timeout is positive", () => {
+      const timeout = 300;
+      const timer = timeout > 0 ? setTimeout(() => {}, timeout * 1000) : null;
+      assert.notEqual(timer, null);
+      if (timer) clearTimeout(timer);
+    });
+  });
 });
diff --git a/src/runners/claude-code.ts b/src/runners/claude-code.ts
index 91280b2..bc7f491 100644
--- a/src/runners/claude-code.ts
+++ b/src/runners/claude-code.ts
@@ -82,28 +82,31 @@ export const claudeCodeRunner: Runner = {
         error += data.toString();
       });
 
-      const timer = setTimeout(() => {
-        if (!settled) {
-          settled = true;
-          child.kill("SIGTERM");
-          resolve({
-            id,
-            worktree: opts.worktreePath,
-            status: "timeout",
-            exitCode: -1,
-            duration: Date.now() - start,
-            output,
-            error: `Timed out after ${opts.timeout}s`,
-            diff: "",
-            filesChanged: [],
-            linesAdded: 0,
-            linesRemoved: 0,
-          });
-        }
-      }, opts.timeout * 1000);
+      const timer =
+        opts.timeout > 0
+          ? setTimeout(() => {
+              if (!settled) {
+                settled = true;
+                child.kill("SIGTERM");
+                resolve({
+                  id,
+                  worktree: opts.worktreePath,
+                  status: "timeout",
+                  exitCode: -1,
+                  duration: Date.now() - start,
+                  output,
+                  error: `Timed out after ${opts.timeout}s`,
+                  diff: "",
+                  filesChanged: [],
+                  linesAdded: 0,
+                  linesRemoved: 0,
+                });
+              }
+            }, opts.timeout * 1000)
+          : null;
 
       child.on("close", async (code) => {
-        clearTimeout(timer);
+        if (timer) clearTimeout(timer);
         if (settled) return;
         settled = true;
 
@@ -136,7 +139,7 @@ export const claudeCodeRunner: Runner = {
       });
 
       child.on("error", (err) => {
-        clearTimeout(timer);
+        if (timer) clearTimeout(timer);
         if (settled) return;
         settled = true;
 
diff --git a/src/types.ts b/src/types.ts
index ceae3ae..43d3df4 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -9,7 +9,7 @@ export interface RunOptions {
   verbose: boolean;
   runner?: string;
   scoring: "weighted" | "copeland";
-  outputFormat: "text" | "json";
+  outputFormat: "text" | "json" | "diff";
   retry?: boolean;
   whitespaceInsensitive?: boolean;
 }