diff --git a/src/index.ts b/src/index.ts
index d29a63a..a8ee30e 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -140,7 +140,9 @@ import {
 import {
   createWorktreeLease,
   cleanWorktreeLease,
+  cancelWorktreeLease,
   formatWorktreeLeaseResult,
+  formatWorktreeCancelResult,
 } from "./worktree-lease.js";
 import { evaluateCommandPolicy, formatCommandPolicyDecision } from "./command-policy.js";
 import {
@@ -373,6 +375,8 @@ program
   .option("--outcomes-file <file>", "Command-outcomes file (JSON array) to include in --export-evidence")
   .option("--create-worktree", "Create a leased git worktree for a mutating delegated agent and exit")
   .option("--clean-worktree", "Clean a leased git worktree after verified completion and exit")
+  .option("--cancel-worktree", "Cancel a leased git worktree, preserving committed work and failing closed on uncommitted work, and exit")
+  .option("--cancel-force", "With --cancel-worktree, discard uncommitted work instead of refusing")
   .option("--agent-identity <id>", "Stable agent identity for a leased worktree (with --create-worktree/--clean-worktree)")
   .option("--worktree-root <dir>", "Directory where leased worktrees live (default <workspace>/.oh-my-cli/worktrees)")
   .option("--command-policy <command>", "Evaluate one shell command against the offline command policy and exit")
@@ -1378,14 +1382,15 @@ program
       // mutating delegated agent, offline (no provider config needed). Exits 0
       // on success (including idempotent no-ops), 1 on a safety refusal, and 2
       // on a usage error or unexpected git failure.
-      if (opts.createWorktree || opts.cleanWorktree) {
+      if (opts.createWorktree || opts.cleanWorktree || opts.cancelWorktree) {
         const format = String(opts.output ?? "text");
         if (format !== "text" && format !== "json") {
           process.stderr.write(`Error: invalid output format "${format}"\n`);
           process.exit(2);
         }
-        if (opts.createWorktree && opts.cleanWorktree) {
-          process.stderr.write("Error: choose one of --create-worktree or --clean-worktree\n");
+        const chosen = [opts.createWorktree, opts.cleanWorktree, opts.cancelWorktree].filter(Boolean).length;
+        if (chosen > 1) {
+          process.stderr.write("Error: choose one of --create-worktree, --clean-worktree, or --cancel-worktree\n");
           process.exit(2);
         }
         if (!opts.taskIdentity) {
@@ -1402,6 +1407,15 @@ program
           agentIdentity: String(opts.agentIdentity),
           worktreeRoot: opts.worktreeRoot,
         };
+        if (opts.cancelWorktree) {
+          const cancelResult = cancelWorktreeLease(leaseOpts, { force: Boolean(opts.cancelForce) });
+          if (format === "json") {
+            process.stdout.write(JSON.stringify(cancelResult) + "\n");
+          } else {
+            process.stdout.write(formatWorktreeCancelResult(cancelResult) + "\n");
+          }
+          process.exit(cancelResult.ok ? 0 : cancelResult.reason === "git_error" ? 2 : 1);
+        }
         const result = opts.createWorktree
           ? createWorktreeLease(leaseOpts)
           : cleanWorktreeLease(leaseOpts);
diff --git a/src/worktree-lease.ts b/src/worktree-lease.ts
index 690df8c..7a4a940 100644
--- a/src/worktree-lease.ts
+++ b/src/worktree-lease.ts
@@ -88,6 +88,39 @@ export type WorktreeCleanResult =
   | { ok: true; lease: WorktreeLease; cleaned: boolean }
   | { ok: false; reason: WorktreeCleanRefusalReason; message: string };
 
+/** Why a lease cancellation was refused (the lease is retained safely). */
+export type WorktreeCancelRefusalReason =
+  | "non_repository"
+  | "ambiguous"
+  | "uncommitted_changes"
+  | "git_error";
+
+/** A commit preserved on the lease branch by a cancellation (bounded, redacted). */
+export interface PreservedCommit {
+  sha: string;
+  subject: string;
+}
+
+/** The committed work a cancellation preserves on the (kept) lease branch. */
+export interface WorktreeCancelPreserved {
+  branch: string;
+  commits: PreservedCommit[];
+  truncatedCommits: number;
+}
+
+export type WorktreeCancelResult =
+  | {
+      ok: true;
+      lease: WorktreeLease;
+      /** False when the lease was already absent (idempotent no-op). */
+      cancelled: boolean;
+      worktreeRemoved: boolean;
+      /** True when uncommitted work was discarded via --cancel-force. */
+      forced: boolean;
+      preserved: WorktreeCancelPreserved;
+    }
+  | { ok: false; reason: WorktreeCancelRefusalReason; message: string };
+
 function redact(text: string): string {
   return redactSecrets(text).text;
 }
@@ -394,6 +427,102 @@ export function cleanWorktreeLease(opts: WorktreeLeaseOptions): WorktreeCleanRes
   return { ok: true, cleaned: true, lease };
 }
 
+// Bound the preserved-commit list so a long-lived lease cannot inflate the report.
+const MAX_PRESERVED_COMMITS = 50;
+
+// List the lease branch's commits not yet in the parent HEAD — the work a
+// cancellation preserves by keeping the branch. Bounded and redacted.
+function collectPreservedCommits(repo: string, branch: string): WorktreeCancelPreserved {
+  const parentHead = git(repo, ["rev-parse", "HEAD"]).stdout.trim();
+  if (!parentHead || !branchRefExists(repo, branch)) {
+    return { branch, commits: [], truncatedCommits: 0 };
+  }
+  const log = git(repo, ["log", "--format=%H%x09%s", `${parentHead}..${branch}`]);
+  const lines = log.stdout.split("\n").filter((line) => line.trim() !== "");
+  const commits = lines.slice(0, MAX_PRESERVED_COMMITS).map((line) => {
+    const tab = line.indexOf("\t");
+    const sha = tab >= 0 ? line.slice(0, tab) : line;
+    const subject = tab >= 0 ? line.slice(tab + 1) : "";
+    return { sha: sha.slice(0, 12), subject: redact(subject) };
+  });
+  return { branch, commits, truncatedCommits: Math.max(0, lines.length - commits.length) };
+}
+
+/**
+ * Cancel a leased workspace: the safe teardown path for a cancelled agent. Unlike
+ * `cleanWorktreeLease` (which requires the work to be merged before deleting the
+ * branch), cancellation PRESERVES committed work by keeping the lease branch and
+ * only removing the worktree, so the agent's commits survive for later integration.
+ * It fails closed when the worktree holds uncommitted changes that would be lost,
+ * unless `force` acknowledges the discard. Idempotent: cancelling an absent lease
+ * is a no-op. The parent worktree is never touched.
+ */
+export function cancelWorktreeLease(
+  opts: WorktreeLeaseOptions,
+  cancelOpts: { force?: boolean } = {},
+): WorktreeCancelResult {
+  const force = Boolean(cancelOpts.force);
+  const repo = path.resolve(opts.repo);
+  const task = (opts.taskIdentity ?? "").trim();
+  const agent = (opts.agentIdentity ?? "").trim();
+  if (!task || !agent) {
+    return {
+      ok: false,
+      reason: "ambiguous",
+      message: "both --task-identity and --agent-identity are required to locate a lease",
+    };
+  }
+
+  const commonDir = repoCommonDir(repo);
+  if (commonDir === null) {
+    return { ok: false, reason: "non_repository", message: "target is not a git repository" };
+  }
+
+  const identity = deriveLeaseIdentity({ repoKey: commonDir, taskIdentity: task, agentIdentity: agent });
+  const worktreeRoot = path.resolve(opts.worktreeRoot ?? defaultWorktreeRoot(commonDir));
+  const worktreePath = path.join(worktreeRoot, identity.leaseId);
+
+  const wtListed = worktreeRegistered(repo, worktreePath);
+  const branchExists = branchRefExists(repo, identity.branch);
+  const baseSha = git(repo, ["rev-parse", "--verify", "--quiet", identity.branch]).stdout.trim();
+  const lease = buildLease({ identity, worktreePath, baseSha, taskIdentity: task, agentIdentity: agent });
+  const emptyPreserved: WorktreeCancelPreserved = { branch: identity.branch, commits: [], truncatedCommits: 0 };
+
+  if (!wtListed && !branchExists) {
+    // Already absent — idempotent no-op.
+    return { ok: true, cancelled: false, worktreeRemoved: false, forced: force, lease, preserved: emptyPreserved };
+  }
+
+  // Fail closed on uncommitted work unless --force acknowledges the loss.
+  const dirty = wtListed ? dirtyCount(worktreePath) : 0;
+  if (dirty > 0 && !force) {
+    return {
+      ok: false,
+      reason: "uncommitted_changes",
+      message: `lease worktree has ${dirty} uncommitted change(s) that would be lost; commit them or pass --cancel-force to discard`,
+    };
+  }
+
+  // Preserve committed work (the branch is kept), then remove the worktree.
+  const preserved = collectPreservedCommits(repo, identity.branch);
+  let worktreeRemoved = false;
+  if (wtListed) {
+    const rm = force
+      ? git(repo, ["worktree", "remove", "--force", worktreePath])
+      : git(repo, ["worktree", "remove", worktreePath]);
+    if (!rm.ok) {
+      return {
+        ok: false,
+        reason: "git_error",
+        message: redact(`git worktree remove failed: ${rm.stderr.trim() || "unknown error"}`),
+      };
+    }
+    worktreeRemoved = true;
+  }
+
+  return { ok: true, cancelled: true, worktreeRemoved, forced: force, lease, preserved };
+}
+
 // --- formatting -------------------------------------------------------------
 
 /** A concise, redacted, human-readable lease result. */
@@ -430,3 +559,35 @@ export function formatWorktreeLeaseResult(
   }
   return lines.join("\n");
 }
+
+/** A concise, redacted, human-readable cancellation result. */
+export function formatWorktreeCancelResult(result: WorktreeCancelResult): string {
+  const lines: string[] = [];
+  lines.push(`Worktree lease cancellation (${WORKTREE_LEASE_SCHEMA} v${WORKTREE_LEASE_VERSION})`);
+  lines.push("─".repeat(40));
+  lines.push("action:   cancel");
+  if (result.ok) {
+    const status = !result.cancelled
+      ? "already absent (idempotent)"
+      : result.forced
+        ? "cancelled (forced; uncommitted work discarded)"
+        : "cancelled";
+    lines.push("result:   ok");
+    lines.push(`status:   ${status}`);
+    lines.push(`lease:    ${result.lease.leaseId}`);
+    lines.push(`branch:   ${result.lease.branch} (preserved)`);
+    lines.push(`worktree: ${result.lease.worktreePath}${result.worktreeRemoved ? " (removed)" : ""}`);
+    lines.push(`preserved commits: ${result.preserved.commits.length}`);
+    for (const commit of result.preserved.commits) {
+      lines.push(`  ${commit.sha}  ${commit.subject}`);
+    }
+    if (result.preserved.truncatedCommits > 0) {
+      lines.push(`  … ${result.preserved.truncatedCommits} more commit(s) beyond the bound`);
+    }
+  } else {
+    lines.push("result:   refused");
+    lines.push(`reason:   ${result.reason}`);
+    lines.push(`detail:   ${redact(result.message)}`);
+  }
+  return lines.join("\n");
+}
diff --git a/tests/integration/cancellation-cleanup.test.ts b/tests/integration/cancellation-cleanup.test.ts
new file mode 100644
index 0000000..22a4d27
--- /dev/null
+++ b/tests/integration/cancellation-cleanup.test.ts
@@ -0,0 +1,133 @@
+import { describe, it, expect, beforeAll, afterAll } from "vitest";
+import { execFileSync } from "node:child_process";
+import { spawn } from "node:child_process";
+import path from "node:path";
+import fs from "node:fs";
+import os from "node:os";
+
+function runCli(
+  args: string[],
+  env: Record<string, string | undefined>,
+  timeoutMs = 20_000,
+): Promise<{ stdout: string; stderr: string; code: number | null }> {
+  return new Promise((resolve, reject) => {
+    const cliPath = path.resolve(import.meta.dirname, "../../dist/index.js");
+    const proc = spawn("node", [cliPath, ...args], {
+      env: { ...process.env, ...env },
+      timeout: timeoutMs,
+    });
+    let stdout = "";
+    let stderr = "";
+    proc.stdout.on("data", (d) => { stdout += d; });
+    proc.stderr.on("data", (d) => { stderr += d; });
+    proc.on("close", (code) => resolve({ stdout, stderr, code }));
+    proc.on("error", reject);
+  });
+}
+
+function git(cwd: string, ...args: string[]): void {
+  execFileSync("git", ["-C", cwd, ...args], { stdio: ["ignore", "pipe", "ignore"] });
+}
+
+const tmpDirs: string[] = [];
+function makeRepo(): string {
+  const repo = fs.mkdtempSync(path.join(os.tmpdir(), "omc-cancel-int-"));
+  tmpDirs.push(repo);
+  execFileSync("git", ["init", "-q", "-b", "main", repo], { stdio: ["ignore", "pipe", "ignore"] });
+  git(repo, "config", "user.email", "test@example.com");
+  git(repo, "config", "user.name", "Test");
+  fs.writeFileSync(path.join(repo, "a.txt"), "base\n");
+  git(repo, "add", "a.txt");
+  git(repo, "commit", "-q", "-m", "base");
+  return repo;
+}
+
+describe("Integration: cancellation cleanup (--cancel-worktree)", () => {
+  let homeDir: string;
+  let env: Record<string, string>;
+
+  beforeAll(() => {
+    homeDir = fs.mkdtempSync(path.join(os.tmpdir(), "omc-cancel-int-home-"));
+    tmpDirs.push(homeDir);
+    env = { HOME: homeDir, OPENAI_API_KEY: "", OPENAI_BASE_URL: "", OPENAI_MODEL: "" };
+  });
+
+  afterAll(() => {
+    for (const d of tmpDirs) fs.rmSync(d, { recursive: true, force: true });
+  });
+
+  async function createLease(repo: string, task: string, agent: string): Promise<string> {
+    const r = await runCli(
+      ["--create-worktree", "--task-identity", task, "--agent-identity", agent, "--workspace", repo, "--output", "json"],
+      env,
+    );
+    expect(r.code).toBe(0);
+    const result = JSON.parse(r.stdout);
+    expect(result.ok).toBe(true);
+    return result.lease.worktreePath as string;
+  }
+
+  it("cancels a clean lease via the CLI: worktree removed, branch preserved", async () => {
+    const repo = makeRepo();
+    const wtPath = await createLease(repo, "task-clean", "agent-1");
+    expect(fs.existsSync(wtPath)).toBe(true);
+
+    const r = await runCli(
+      ["--cancel-worktree", "--task-identity", "task-clean", "--agent-identity", "agent-1", "--workspace", repo, "--output", "json"],
+      env,
+    );
+    expect(r.code).toBe(0);
+    const result = JSON.parse(r.stdout);
+    expect(result.ok).toBe(true);
+    expect(result.cancelled).toBe(true);
+    expect(result.worktreeRemoved).toBe(true);
+    expect(fs.existsSync(wtPath)).toBe(false);
+    // The lease branch is preserved.
+    const branches = execFileSync("git", ["-C", repo, "branch", "--list", "lease/wt-*"], { encoding: "utf8" });
+    expect(branches.trim()).not.toBe("");
+  });
+
+  it("refuses to cancel a dirty lease without --cancel-force (exit 1)", async () => {
+    const repo = makeRepo();
+    const wtPath = await createLease(repo, "task-dirty", "agent-1");
+    fs.writeFileSync(path.join(wtPath, "c.txt"), "uncommitted\n");
+
+    const r = await runCli(
+      ["--cancel-worktree", "--task-identity", "task-dirty", "--agent-identity", "agent-1", "--workspace", repo, "--output", "json"],
+      env,
+    );
+    expect(r.code).toBe(1);
+    const result = JSON.parse(r.stdout);
+    expect(result.ok).toBe(false);
+    expect(result.reason).toBe("uncommitted_changes");
+    // The worktree is retained.
+    expect(fs.existsSync(wtPath)).toBe(true);
+  });
+
+  it("discards uncommitted work with --cancel-force (exit 0)", async () => {
+    const repo = makeRepo();
+    const wtPath = await createLease(repo, "task-force", "agent-1");
+    fs.writeFileSync(path.join(wtPath, "c.txt"), "uncommitted\n");
+
+    const r = await runCli(
+      ["--cancel-worktree", "--cancel-force", "--task-identity", "task-force", "--agent-identity", "agent-1", "--workspace", repo, "--output", "json"],
+      env,
+    );
+    expect(r.code).toBe(0);
+    const result = JSON.parse(r.stdout);
+    expect(result.ok).toBe(true);
+    expect(result.forced).toBe(true);
+    expect(result.worktreeRemoved).toBe(true);
+    expect(fs.existsSync(wtPath)).toBe(false);
+  });
+
+  it("rejects combining --cancel-worktree with --clean-worktree (exit 2)", async () => {
+    const repo = makeRepo();
+    const r = await runCli(
+      ["--cancel-worktree", "--clean-worktree", "--task-identity", "t", "--agent-identity", "a", "--workspace", repo],
+      env,
+    );
+    expect(r.code).toBe(2);
+    expect(r.stderr).toContain("choose one of");
+  });
+});
diff --git a/tests/unit/cancellation-cleanup.test.ts b/tests/unit/cancellation-cleanup.test.ts
new file mode 100644
index 0000000..7f8d6cd
--- /dev/null
+++ b/tests/unit/cancellation-cleanup.test.ts
@@ -0,0 +1,165 @@
+import { describe, it, expect, afterAll } from "vitest";
+import { execFileSync } from "node:child_process";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import {
+  createWorktreeLease,
+  cancelWorktreeLease,
+  formatWorktreeCancelResult,
+  WORKTREE_LEASE_SCHEMA,
+  WORKTREE_LEASE_VERSION,
+} from "../../src/worktree-lease.js";
+
+const tmpDirs: string[] = [];
+afterAll(() => {
+  for (const d of tmpDirs) fs.rmSync(d, { recursive: true, force: true });
+});
+
+function git(cwd: string, ...args: string[]): void {
+  execFileSync("git", ["-C", cwd, ...args], { stdio: ["ignore", "pipe", "ignore"] });
+}
+
+// A temp repo with one commit on `main`.
+function makeRepo(): string {
+  const repo = fs.mkdtempSync(path.join(os.tmpdir(), "omc-cancel-"));
+  tmpDirs.push(repo);
+  execFileSync("git", ["init", "-q", "-b", "main", repo], { stdio: ["ignore", "pipe", "ignore"] });
+  git(repo, "config", "user.email", "test@example.com");
+  git(repo, "config", "user.name", "Test");
+  fs.writeFileSync(path.join(repo, "a.txt"), "base\n");
+  git(repo, "add", "a.txt");
+  git(repo, "commit", "-q", "-m", "base");
+  return repo;
+}
+
+function createLease(repo: string): string {
+  const result = createWorktreeLease({ repo, taskIdentity: "task-1", agentIdentity: "agent-1" });
+  if (!result.ok) throw new Error(`create failed: ${result.reason}`);
+  return result.lease.worktreePath;
+}
+
+describe("cancelWorktreeLease", () => {
+  it("cancels a clean lease: removes the worktree, preserves the branch", () => {
+    const repo = makeRepo();
+    const wtPath = createLease(repo);
+    expect(fs.existsSync(wtPath)).toBe(true);
+
+    const result = cancelWorktreeLease({ repo, taskIdentity: "task-1", agentIdentity: "agent-1" });
+    expect(result.ok).toBe(true);
+    if (result.ok) {
+      expect(result.cancelled).toBe(true);
+      expect(result.worktreeRemoved).toBe(true);
+      expect(result.forced).toBe(false);
+    }
+    // The worktree is gone but the lease branch is preserved.
+    expect(fs.existsSync(wtPath)).toBe(false);
+    const branches = execFileSync("git", ["-C", repo, "branch", "--list", "lease/wt-*"], { encoding: "utf8" });
+    expect(branches.trim()).not.toBe("");
+  });
+
+  it("preserves committed work and reports the preserved commits", () => {
+    const repo = makeRepo();
+    const wtPath = createLease(repo);
+    fs.writeFileSync(path.join(wtPath, "b.txt"), "agent work\n");
+    git(wtPath, "add", "b.txt");
+    git(wtPath, "commit", "-q", "-m", "agent commit");
+
+    const result = cancelWorktreeLease({ repo, taskIdentity: "task-1", agentIdentity: "agent-1" });
+    expect(result.ok).toBe(true);
+    if (result.ok) {
+      expect(result.cancelled).toBe(true);
+      expect(result.preserved.commits.map((c) => c.subject)).toContain("agent commit");
+      // The branch (with the commit) still exists.
+      expect(execFileSync("git", ["-C", repo, "branch", "--list", result.lease.branch], { encoding: "utf8" }).trim()).not.toBe("");
+    }
+  });
+
+  it("fails closed on uncommitted work without --cancel-force", () => {
+    const repo = makeRepo();
+    const wtPath = createLease(repo);
+    fs.writeFileSync(path.join(wtPath, "c.txt"), "uncommitted\n");
+
+    const result = cancelWorktreeLease({ repo, taskIdentity: "task-1", agentIdentity: "agent-1" });
+    expect(result.ok).toBe(false);
+    if (!result.ok) {
+      expect(result.reason).toBe("uncommitted_changes");
+    }
+    // The worktree is retained (not removed).
+    expect(fs.existsSync(wtPath)).toBe(true);
+  });
+
+  it("discards uncommitted work with --cancel-force", () => {
+    const repo = makeRepo();
+    const wtPath = createLease(repo);
+    fs.writeFileSync(path.join(wtPath, "c.txt"), "uncommitted\n");
+
+    const result = cancelWorktreeLease({ repo, taskIdentity: "task-1", agentIdentity: "agent-1" }, { force: true });
+    expect(result.ok).toBe(true);
+    if (result.ok) {
+      expect(result.cancelled).toBe(true);
+      expect(result.forced).toBe(true);
+      expect(result.worktreeRemoved).toBe(true);
+    }
+    expect(fs.existsSync(wtPath)).toBe(false);
+  });
+
+  it("is an idempotent no-op when the lease is already absent", () => {
+    const repo = makeRepo();
+    const result = cancelWorktreeLease({ repo, taskIdentity: "never-leased", agentIdentity: "agent-x" });
+    expect(result.ok).toBe(true);
+    if (result.ok) {
+      expect(result.cancelled).toBe(false);
+      expect(result.worktreeRemoved).toBe(false);
+    }
+  });
+
+  it("fails closed when identities are missing", () => {
+    const repo = makeRepo();
+    const result = cancelWorktreeLease({ repo, taskIdentity: "", agentIdentity: "" });
+    expect(result.ok).toBe(false);
+    if (!result.ok) expect(result.reason).toBe("ambiguous");
+  });
+});
+
+describe("formatWorktreeCancelResult", () => {
+  it("renders a successful cancellation with preserved commits", () => {
+    const text = formatWorktreeCancelResult({
+      ok: true,
+      cancelled: true,
+      worktreeRemoved: true,
+      forced: false,
+      lease: {
+        schema: WORKTREE_LEASE_SCHEMA,
+        v: WORKTREE_LEASE_VERSION,
+        leaseId: "abc123",
+        branch: "lease/wt-abc123",
+        worktreePath: "~/repo/.oh-my-cli/worktrees/abc123",
+        baseSha: "def456",
+        taskIdentity: "task",
+        agentIdentity: "agent",
+      },
+      preserved: {
+        branch: "lease/wt-abc123",
+        commits: [{ sha: "1234567890ab", subject: "agent commit" }],
+        truncatedCommits: 0,
+      },
+    });
+    expect(text).toContain("Worktree lease cancellation");
+    expect(text).toContain("status:   cancelled");
+    expect(text).toContain("branch:   lease/wt-abc123 (preserved)");
+    expect(text).toContain("(removed)");
+    expect(text).toContain("preserved commits: 1");
+    expect(text).toContain("agent commit");
+  });
+
+  it("renders a refusal", () => {
+    const text = formatWorktreeCancelResult({
+      ok: false,
+      reason: "uncommitted_changes",
+      message: "lease worktree has 1 uncommitted change(s) that would be lost",
+    });
+    expect(text).toContain("result:   refused");
+    expect(text).toContain("reason:   uncommitted_changes");
+  });
+});