diff --git a/src/cli.ts b/src/cli.ts
index bce3e7b..443a8fb 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -17,12 +17,13 @@ program
 
 program
   .command("run")
-  .description("Run a task with N parallel Claude Code agents")
+  .description("Run a task with N parallel AI coding agents")
   .argument("<prompt>", "The coding task to perform")
   .option("-n, --attempts <number>", "Number of parallel attempts", "3")
   .option("-t, --test-cmd <command>", "Test command to verify results (e.g., 'npm test')")
   .option("--timeout <seconds>", "Timeout per agent in seconds", "300")
   .option("--model <model>", "Claude model to use", "sonnet")
+  .option("-r, --runner <name>", "AI coding tool to use (default: claude-code)")
   .option("--verbose", "Show detailed output from each agent")
   .action(async (prompt: string, opts) => {
     const attempts = parseInt(opts.attempts, 10);
@@ -50,6 +51,7 @@ program
       testCmd: opts.testCmd,
       timeout,
       model: opts.model,
+      runner: opts.runner,
       verbose: opts.verbose ?? false,
     });
   });
diff --git a/src/commands/run.ts b/src/commands/run.ts
index bc08163..e66459b 100644
--- a/src/commands/run.ts
+++ b/src/commands/run.ts
@@ -1,15 +1,31 @@
 import { mkdir, writeFile } from "node:fs/promises";
 import { join } from "node:path";
-import { runClaudeAgent } from "../runners/claude-code.js";
+import { getDefaultRunner, getRunner } from "../runners/registry.js";
 import { analyzeConvergence, recommend } from "../scoring/convergence.js";
 import { runTests } from "../scoring/test-runner.js";
 import type { AgentResult, EnsembleResult, RunOptions } from "../types.js";
 import { displayApplyInstructions, displayHeader, displayResults } from "../utils/display.js";
-import { cleanupBranches, createWorktree, removeWorktree } from "../utils/git.js";
+import { cleanupBranches, createWorktree } from "../utils/git.js";
 
 export async function run(opts: RunOptions): Promise<void> {
   displayHeader(opts.prompt, opts.attempts, opts.model);
 
+  // Resolve runner
+  const runner = opts.runner ? getRunner(opts.runner) : getDefaultRunner();
+  if (!runner) {
+    console.error(`  Unknown runner: ${opts.runner}`);
+    console.error("  Available runners: claude-code");
+    process.exit(1);
+  }
+
+  const isAvailable = await runner.available();
+  if (!isAvailable) {
+    console.error(
+      `  Runner "${runner.name}" is not available. Is ${runner.description} installed?`,
+    );
+    process.exit(1);
+  }
+
   // Clean up any leftover worktrees/branches from previous runs
   await cleanupBranches().catch(() => {});
 
@@ -25,11 +41,17 @@ export async function run(opts: RunOptions): Promise<void> {
   console.log();
 
   // Phase 2: Run agents in parallel
-  console.log(`  Running ${opts.attempts} agents in parallel...`);
+  console.log(`  Running ${opts.attempts} agents in parallel (${runner.name})...`);
   console.log();
 
   const agentPromises = worktrees.map(({ id, path }) =>
-    runClaudeAgent(id, opts.prompt, path, opts.model, opts.timeout, opts.verbose),
+    runner.run(id, {
+      prompt: opts.prompt,
+      worktreePath: path,
+      model: opts.model,
+      timeout: opts.timeout,
+      verbose: opts.verbose,
+    }),
   );
 
   const agents: AgentResult[] = await Promise.all(agentPromises);
diff --git a/src/runners/base.ts b/src/runners/base.ts
new file mode 100644
index 0000000..4533281
--- /dev/null
+++ b/src/runners/base.ts
@@ -0,0 +1,27 @@
+import type { AgentResult } from "../types.js";
+
+export interface RunnerOptions {
+  prompt: string;
+  worktreePath: string;
+  model: string;
+  timeout: number;
+  verbose: boolean;
+}
+
+/**
+ * Interface for AI coding tool runners. Each runner wraps a specific
+ * tool (Claude Code, Aider, etc.) and executes a task in a worktree.
+ */
+export interface Runner {
+  /** Unique identifier for this runner (e.g., "claude-code", "aider") */
+  name: string;
+
+  /** Human-readable description */
+  description: string;
+
+  /** Check if this runner's tool is installed and available */
+  available(): Promise<boolean>;
+
+  /** Execute a task and return the result */
+  run(id: number, opts: RunnerOptions): Promise<AgentResult>;
+}
diff --git a/src/runners/claude-code.ts b/src/runners/claude-code.ts
index 4c34798..1ce9b59 100644
--- a/src/runners/claude-code.ts
+++ b/src/runners/claude-code.ts
@@ -1,118 +1,127 @@
 import { spawn } from "node:child_process";
 import type { AgentResult } from "../types.js";
 import { getDiff, getDiffStats } from "../utils/git.js";
+import type { Runner, RunnerOptions } from "./base.js";
 
-export async function runClaudeAgent(
-  id: number,
-  prompt: string,
-  worktreePath: string,
-  model: string,
-  timeout: number,
-  verbose: boolean,
-): Promise<AgentResult> {
-  const start = Date.now();
-
+async function isClaudeInstalled(): Promise<boolean> {
   return new Promise((resolve) => {
-    let output = "";
-    let error = "";
-    let settled = false;
+    const child = spawn("claude", ["--version"], { stdio: "ignore" });
+    child.on("close", (code) => resolve(code === 0));
+    child.on("error", () => resolve(false));
+  });
+}
 
-    const args = [
-      "-p",
-      prompt,
-      "--output-format",
-      "text",
-      "--model",
-      model,
-      "--max-turns",
-      "50",
-      "--allowedTools",
-      "Edit",
-      "Write",
-      "Read",
-      "Glob",
-      "Grep",
-      "Bash",
-    ];
+export const claudeCodeRunner: Runner = {
+  name: "claude-code",
+  description: "Claude Code CLI (claude -p)",
 
-    const child = spawn("claude", args, {
-      cwd: worktreePath,
-      stdio: ["ignore", "pipe", "pipe"],
-      env: { ...process.env },
-    });
+  available: isClaudeInstalled,
 
-    child.stdout.on("data", (data: Buffer) => {
-      const chunk = data.toString();
-      output += chunk;
-      if (verbose) {
-        process.stdout.write(`  [agent ${id}] ${chunk}`);
-      }
-    });
+  async run(id: number, opts: RunnerOptions): Promise<AgentResult> {
+    const start = Date.now();
 
-    child.stderr.on("data", (data: Buffer) => {
-      error += data.toString();
-    });
+    return new Promise((resolve) => {
+      let output = "";
+      let error = "";
+      let settled = false;
+
+      const args = [
+        "-p",
+        opts.prompt,
+        "--output-format",
+        "text",
+        "--model",
+        opts.model,
+        "--max-turns",
+        "50",
+        "--allowedTools",
+        "Edit",
+        "Write",
+        "Read",
+        "Glob",
+        "Grep",
+        "Bash",
+      ];
+
+      const child = spawn("claude", args, {
+        cwd: opts.worktreePath,
+        stdio: ["ignore", "pipe", "pipe"],
+        env: { ...process.env },
+      });
 
-    const timer = setTimeout(() => {
-      if (!settled) {
+      child.stdout.on("data", (data: Buffer) => {
+        const chunk = data.toString();
+        output += chunk;
+        if (opts.verbose) {
+          process.stdout.write(`  [agent ${id}] ${chunk}`);
+        }
+      });
+
+      child.stderr.on("data", (data: Buffer) => {
+        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);
+
+      child.on("close", async (code) => {
+        clearTimeout(timer);
+        if (settled) return;
         settled = true;
-        child.kill("SIGTERM");
+
+        const duration = Date.now() - start;
+        const diff = await getDiff(opts.worktreePath);
+        const stats = await getDiffStats(opts.worktreePath);
+
         resolve({
           id,
-          worktree: worktreePath,
-          status: "timeout",
+          worktree: opts.worktreePath,
+          status: code === 0 ? "success" : "error",
+          exitCode: code ?? 1,
+          duration,
+          output,
+          error: error || undefined,
+          diff,
+          ...stats,
+        });
+      });
+
+      child.on("error", (err) => {
+        clearTimeout(timer);
+        if (settled) return;
+        settled = true;
+
+        resolve({
+          id,
+          worktree: opts.worktreePath,
+          status: "error",
           exitCode: -1,
           duration: Date.now() - start,
           output,
-          error: `Timed out after ${timeout}s`,
+          error: err.message,
           diff: "",
           filesChanged: [],
           linesAdded: 0,
           linesRemoved: 0,
         });
-      }
-    }, timeout * 1000);
-
-    child.on("close", async (code) => {
-      clearTimeout(timer);
-      if (settled) return;
-      settled = true;
-
-      const duration = Date.now() - start;
-      const diff = await getDiff(worktreePath);
-      const stats = await getDiffStats(worktreePath);
-
-      resolve({
-        id,
-        worktree: worktreePath,
-        status: code === 0 ? "success" : "error",
-        exitCode: code ?? 1,
-        duration,
-        output,
-        error: error || undefined,
-        diff,
-        ...stats,
-      });
-    });
-
-    child.on("error", (err) => {
-      clearTimeout(timer);
-      if (settled) return;
-      settled = true;
-
-      resolve({
-        id,
-        worktree: worktreePath,
-        status: "error",
-        exitCode: -1,
-        duration: Date.now() - start,
-        output,
-        error: err.message,
-        diff: "",
-        filesChanged: [],
-        linesAdded: 0,
-        linesRemoved: 0,
       });
     });
-  });
-}
+  },
+};
diff --git a/src/runners/registry.test.ts b/src/runners/registry.test.ts
new file mode 100644
index 0000000..64de6ad
--- /dev/null
+++ b/src/runners/registry.test.ts
@@ -0,0 +1,36 @@
+import assert from "node:assert/strict";
+import { describe, it } from "node:test";
+import { getDefaultRunner, getRunner, listRunners } from "./registry.js";
+
+describe("runner registry", () => {
+  it("returns claude-code runner by name", () => {
+    const runner = getRunner("claude-code");
+    assert.ok(runner);
+    assert.equal(runner.name, "claude-code");
+  });
+
+  it("returns undefined for unknown runner", () => {
+    const runner = getRunner("nonexistent");
+    assert.equal(runner, undefined);
+  });
+
+  it("lists all available runners", () => {
+    const runners = listRunners();
+    assert.ok(runners.length >= 1);
+    assert.ok(runners.some((r) => r.name === "claude-code"));
+  });
+
+  it("returns claude-code as default runner", () => {
+    const runner = getDefaultRunner();
+    assert.equal(runner.name, "claude-code");
+  });
+
+  it("claude-code runner has required interface fields", () => {
+    const runner = getRunner("claude-code");
+    assert.ok(runner);
+    assert.equal(typeof runner.name, "string");
+    assert.equal(typeof runner.description, "string");
+    assert.equal(typeof runner.available, "function");
+    assert.equal(typeof runner.run, "function");
+  });
+});
diff --git a/src/runners/registry.ts b/src/runners/registry.ts
new file mode 100644
index 0000000..12fc579
--- /dev/null
+++ b/src/runners/registry.ts
@@ -0,0 +1,16 @@
+import type { Runner } from "./base.js";
+import { claudeCodeRunner } from "./claude-code.js";
+
+const runners = new Map<string, Runner>([["claude-code", claudeCodeRunner]]);
+
+export function getRunner(name: string): Runner | undefined {
+  return runners.get(name);
+}
+
+export function listRunners(): Runner[] {
+  return [...runners.values()];
+}
+
+export function getDefaultRunner(): Runner {
+  return claudeCodeRunner;
+}
diff --git a/src/types.ts b/src/types.ts
index bde75a0..076d733 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -5,6 +5,7 @@ export interface RunOptions {
   timeout: number;
   model: string;
   verbose: boolean;
+  runner?: string;
 }
 
 export interface AgentResult {