diff --git a/web/src/fastForward.test.ts b/web/src/fastForward.test.ts
new file mode 100644
index 0000000..4acd661
--- /dev/null
+++ b/web/src/fastForward.test.ts
@@ -0,0 +1,93 @@
+import { describe, expect, it } from "vitest";
+import {
+  buildFastForwardRequest,
+  fastForwardSeed,
+  resolveFastForward,
+} from "./fastForward.js";
+import type { Project, SpawnPreset } from "./types.js";
+
+const presets: SpawnPreset[] = [
+  { id: "custom", label: "Custom…", command: "" },
+  { id: "claude", label: "Claude", command: "claude" },
+];
+
+function project(overrides: Partial<Project>): Project {
+  return {
+    path: "/repos/p",
+    name: "p",
+    last_activity: new Date().toISOString(),
+    ...overrides,
+  };
+}
+
+describe("resolveFastForward (#67)", () => {
+  it("resolves every default from the most recent project", () => {
+    const projects = [
+      project({ path: "/repos/old", name: "old", last_activity: "2020-01-01T00:00:00Z" }),
+      project({
+        path: "/repos/fresh",
+        name: "fresh",
+        base_repo: "/repos/fresh",
+        last_command: "aider",
+      }),
+    ];
+    const res = resolveFastForward(projects, presets, "amber-falcon");
+    expect(res.project?.path).toBe("/repos/fresh");
+    expect(res.command).toBe("aider");
+    expect(res.name).toBe("amber-falcon");
+
+    const req = buildFastForwardRequest(res)!;
+    expect(req.cwd).toBe("/repos/fresh");
+    expect(req.command).toBe("aider");
+    expect(req.metadata).toEqual({ name: "amber-falcon" });
+    expect(req.worktree).toEqual({
+      base_repo: "/repos/fresh",
+      branch: "amber-falcon",
+      cleanup_on_kill: true,
+      create_branch: true,
+    });
+  });
+
+  it("falls back to the first non-custom preset when there is no last command", () => {
+    const res = resolveFastForward([project({ last_command: undefined })], presets, "n");
+    expect(res.command).toBe("claude");
+  });
+
+  it("treats an empty last command as no command", () => {
+    const res = resolveFastForward([project({ last_command: "" })], [presets[0]], "n");
+    expect(res.command).toBeUndefined();
+    expect(buildFastForwardRequest(res)).toBeNull();
+  });
+
+  it("resolves nothing when no projects are known yet", () => {
+    const res = resolveFastForward([], presets, "n");
+    expect(res.project).toBeUndefined();
+    expect(buildFastForwardRequest(res)).toBeNull();
+  });
+
+  it("downgrades to a draft when the generated name is missing", () => {
+    const res = resolveFastForward([project({ last_command: "claude" })], presets);
+    expect(res.name).toBeUndefined();
+    expect(buildFastForwardRequest(res)).toBeNull();
+  });
+
+  it("seeds the fallback draft with whatever did resolve", () => {
+    const res = resolveFastForward(
+      [project({ path: "/repos/p", base_repo: "/repos/p", last_command: "aider" })],
+      presets,
+    );
+    expect(fastForwardSeed(res)).toEqual({
+      cwd: "/repos/p",
+      command: "aider",
+      name: "",
+      worktreeEnabled: true,
+      worktreeBranch: undefined,
+    });
+  });
+
+  it("seeds worktree off when not even a project resolved", () => {
+    const seed = fastForwardSeed(resolveFastForward([], presets));
+    expect(seed.worktreeEnabled).toBe(false);
+    expect(seed.cwd).toBe("");
+  });
+});
diff --git a/web/src/fastForward.ts b/web/src/fastForward.ts
new file mode 100644
index 0000000..fe05dd5
--- /dev/null
+++ b/web/src/fastForward.ts
@@ -0,0 +1,62 @@
+// Fast-forward spawn (#67): one keystroke, every default resolved, no form.
+// Pure resolution only — the caller (main.ts) owns the fetches and the POST,
+// and falls back to a seeded draft pane when anything is missing.
+
+import type { CreateSessionRequest, Project, SpawnPreset } from "./types.js";
+import { sortProjects } from "./projectList.js";
+
+/** What one fast-forward keystroke resolved. Anything absent means "open a
+ *  draft pre-filled with the rest instead of spawning". */
+export interface FastForwardResolution {
+  project?: Project;
+  command?: string;
+  name?: string;
+}
+
+/** The defaults: most recent project (fresh-first, same ordering the picker
+ *  shows), its last command falling back to the first non-custom preset, and
+ *  a freshly generated name when the daemon supplied one. */
+export function resolveFastForward(
+  projects: Project[],
+  presets: SpawnPreset[],
+  name?: string,
+): FastForwardResolution {
+  const project = sortProjects(projects, new Date())[0];
+  const lastCommand = project?.last_command?.trim();
+  const command =
+    lastCommand || presets.find((p) => p.command !== "")?.command || undefined;
+  return { project, command, name: name || undefined };
+}
+
+/** The immediate spawn request — worktree on, new branch named after the
+ *  generated session name — or `null` when any default is missing. */
+export function buildFastForwardRequest(
+  res: FastForwardResolution,
+): CreateSessionRequest | null {
+  const { project, command, name } = res;
+  if (!project || !command?.trim() || !name) return null;
+  return {
+    cwd: project.path,
+    command,
+    metadata: { name },
+    worktree: {
+      base_repo: project.base_repo ?? project.path,
+      branch: name,
+      cleanup_on_kill: true,
+      create_branch: true,
+    },
+  };
+}
+
+/** Seed for the fallback draft pane: whatever did resolve goes into the
+ *  form; the rest stays with its own defaults. */
+export function fastForwardSeed(res: FastForwardResolution) {
+  return {
+    cwd: res.project?.path ?? "",
+    command: res.command ?? "",
+    name: res.name ?? "",
+    worktreeEnabled: Boolean(res.project),
+    worktreeBranch:
+      res.project && res.name ? res.name : undefined,
+  };
+}