FN-5675: add mission branch strategy and planning breakdown controls

Add mission-level branch strategy support and expose planning breakdown controls across mission flows. - Extend mission/core data models and store logic to track and persist base-branch strategy metadata. - Update mission API routes and legacy adapters to read/write new mission branch strategy fields. - Enhance MissionManager and PlanningModeModal UX to configure branch strategy and planning breakdown behavior. - Add/adjust coverage across core, dashboard, and roadmap plugin tests for mission branch and planning flow behavior. - Add a changeset and mission docs updates for the new mission branch strategy behavior. Files changed: .changeset/fn-5675-mission-branch-strategy.md | 9 + docs/missions.md | 13 ++ packages/core/src/__tests__/db-migrate.test.ts | 12 +- .../src/__tests__/db-mission-base-branch.test.ts | 14 +- packages/core/src/__tests__/db.test.ts | 34 ++-- packages/core/src/__tests__/goals-schema.test.ts | 2 +- packages/core/src/__tests__/insight-store.test.ts | 10 +- packages/core/src/__tests__/mission-store.test.ts | 148 +++++++++++++- packages/core/src/__tests__/run-audit.test.ts | 2 +- packages/core/src/__tests__/secrets-schema.test.ts | 6 +- .../core/src/__tests__/store-merge-queue.test.ts | 2 +- packages/core/src/__tests__/task-documents.test.ts | 2 +- packages/core/src/db.ts | 9 +- packages/core/src/index.ts | 1 + packages/core/src/mission-store.ts | 64 ++++-- packages/core/src/mission-types.ts | 9 + packages/dashboard/app/api/legacy.ts | 23 ++- .../dashboard/app/components/MissionManager.tsx | 226 +++++++++++++++++++-- .../dashboard/app/components/PlanningModeModal.tsx | 9 +- .../components/__tests__/MissionManager.test.tsx | 100 +++++++++ .../PlanningModeModal.planning-flow.test.tsx | 91 +++++++++ packages/dashboard/app/components/mission-types.ts | 4 + .../dashboard/src/__tests__/mission-e2e.test.ts | 49 ++++- packages/dashboard/src/mission-routes.ts | 41 +++- .../src/store/__tests__/roadmap-store.test.ts | 4 +- 25 files changed, 808 insertions(+), 76 deletions(-) Fusion-Task-Id: FN-5675 Fusion-Task-Lineage: cfd13c13-9eff-4b82-90c3-88505d51bfb2
2026-05-29 15:25:47 -07:00
parent dae4c0ea5d
commit 0605d13ab5
25 changed files with 808 additions and 76 deletions
--- a/packages/core/src/tests/db-migrate.test.ts
+++ b/packages/core/src/tests/db-migrate.test.ts
@@ -715,7 +715,7 @@ describe("schema migration", () => {

    const row = db.prepare("SELECT deletedAt FROM tasks WHERE id = 'FN-legacy'").get() as { deletedAt: string | null };
    expect(row.deletedAt).toBeNull();
-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    db.close();
  });
@@ -748,7 +748,7 @@ describe("schema migration", () => {
      { id: "WS-001", mode: "prompt", gateMode: "advisory" },
      { id: "WS-002", mode: "script", gateMode: "advisory" },
    ]);
-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    db.close();
  });
@@ -798,7 +798,7 @@ describe("schema migration", () => {
      reviewerContextRetryCount: 0,
      reviewerFallbackRetryCount: 0,
    });
-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    db.close();
  });
@@ -827,7 +827,7 @@ describe("schema migration", () => {

    const columns = db.prepare("PRAGMA table_info(milestones)").all() as Array<{ name: string }>;
    expect(columns.map((column) => column.name)).toContain("acceptanceCriteria");
-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    db.close();
  });
@@ -868,7 +868,7 @@ describe("schema migration", () => {
    const missionColumns = db.prepare("PRAGMA table_info(missions)").all() as Array<{ name: string }>;
    expect(missionColumns.map((column) => column.name)).toContain("autoMerge");

-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);
    db.close();
  });

@@ -902,7 +902,7 @@ describe("schema migration", () => {
      { id: "WS-002", mode: "script", enabled: 1, gateMode: "advisory" },
      { id: "WS-003", mode: "prompt", enabled: 0, gateMode: "advisory" },
    ]);
-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    db.close();
  });
--- a/packages/core/src/tests/db-mission-base-branch.test.ts
+++ b/packages/core/src/tests/db-mission-base-branch.test.ts
@@ -10,7 +10,7 @@ function makeTmpDir(): string {
  return mkdtempSync(join(tmpdir(), "kb-db-mission-base-branch-"));
 }

-describe("mission baseBranch persistence", () => {
+describe("mission branch strategy persistence", () => {
  let tmpDir: string;
  let fusionDir: string;
  let db: Database;
@@ -29,21 +29,29 @@ describe("mission baseBranch persistence", () => {
    await rm(tmpDir, { recursive: true, force: true });
  });

-  it("creates, reads, and updates mission baseBranch", () => {
+  it("creates, reads, and updates mission baseBranch and branchStrategy", () => {
    const created = store.createMission({
      title: "Mission",
      baseBranch: "develop",
+      branchStrategy: { mode: "existing", branchName: "release/shared" },
    });

    expect(created.baseBranch).toBe("develop");
+    expect(created.branchStrategy).toEqual({ mode: "existing", branchName: "release/shared" });

    const fetched = store.getMission(created.id);
    expect(fetched?.baseBranch).toBe("develop");
+    expect(fetched?.branchStrategy).toEqual({ mode: "existing", branchName: "release/shared" });

-    const updated = store.updateMission(created.id, { baseBranch: "release/1.0" });
+    const updated = store.updateMission(created.id, {
+      baseBranch: "release/1.0",
+      branchStrategy: { mode: "auto-per-task" },
+    });
    expect(updated.baseBranch).toBe("release/1.0");
+    expect(updated.branchStrategy).toEqual({ mode: "auto-per-task" });

    const refetched = store.getMission(created.id);
    expect(refetched?.baseBranch).toBe("release/1.0");
+    expect(refetched?.branchStrategy).toEqual({ mode: "auto-per-task" });
  });
 });
--- a/packages/core/src/tests/db.test.ts
+++ b/packages/core/src/tests/db.test.ts
@@ -330,7 +330,7 @@ describe("Database", () => {
    });

    it("seeds schema version", () => {
-      expect(db.getSchemaVersion()).toBe(97);
+      expect(db.getSchemaVersion()).toBe(98);
    });

    it("includes tokenUsageCacheWriteTokens on freshly initialized tasks table", () => {
@@ -389,7 +389,7 @@ describe("Database", () => {

    it("is idempotent - calling init() twice does not fail", () => {
      expect(() => db.init()).not.toThrow();
-      expect(db.getSchemaVersion()).toBe(97);
+      expect(db.getSchemaVersion()).toBe(98);
    });
    it("does not overwrite existing config on re-init", () => {
      // Update the config
@@ -1459,7 +1459,7 @@ describe("schema migrations", () => {
    db.init();

    // Verify version bumped to 29 (includes v1→v2 through v26→v29)
-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    // Verify new columns exist and existing data is intact
    const cols = db.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
@@ -1484,11 +1484,11 @@ describe("schema migrations", () => {
    const db = new Database(fusionDir);
    db.init();

-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    // Re-init should not fail
    db.init();
-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    db.close();
  });
@@ -1523,7 +1523,7 @@ describe("schema migrations", () => {

    db.init();

-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    const cols = db.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
    expect(cols.map((col) => col.name)).toContain("priority");
@@ -1564,7 +1564,7 @@ describe("schema migrations", () => {

    db.init();

-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    const cols = db.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
    const colNames = cols.map((col) => col.name);
@@ -1636,7 +1636,7 @@ describe("schema migrations", () => {

    db.init();

-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    const cols = db.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
    const colNames = cols.map((col) => col.name);
@@ -1876,7 +1876,7 @@ describe("schema migrations", () => {

    db.init();

-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    const cols = db.prepare("PRAGMA table_info(chat_messages)").all() as Array<{ name: string }>;
    expect(cols.map((col) => col.name)).toContain("attachments");
@@ -1950,7 +1950,7 @@ describe("schema migrations", () => {

    db.init();

-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    const tables = db.prepare("SELECT name FROM sqlite_master WHERE type='table' AND name = 'agentRatings'").all() as Array<{ name: string }>;
    expect(tables).toEqual([{ name: "agentRatings" }]);
@@ -1974,7 +1974,7 @@ describe("schema migrations", () => {

    db.init();

-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    const tables = db.prepare("SELECT name FROM sqlite_master WHERE type='table' AND name = 'mission_events'").all() as Array<{ name: string }>;
    expect(tables).toEqual([{ name: "mission_events" }]);
@@ -2078,7 +2078,7 @@ describe("schema migrations", () => {
    db.init();

    // Verify version bumped to 29
-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    // Verify new columns exist and existing data is intact
    const cols = db.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
@@ -2297,7 +2297,7 @@ describe("schema migrations", () => {

    localDb.init();

-    expect(localDb.getSchemaVersion()).toBe(97);
+    expect(localDb.getSchemaVersion()).toBe(98);
    const columns = localDb.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
    expect(columns.map((column) => column.name)).toContain("tokenUsageCacheWriteTokens");

@@ -2608,7 +2608,7 @@ describe("createDatabase factory", () => {
    const db = createDatabase(fusionDir);
    db.init();

-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);
    expect(db.getLastModified()).toBeGreaterThan(0);

    db.close();
@@ -2762,7 +2762,7 @@ describe("migration v77 task token budget columns", () => {

      migrated = new Database(fusion);
      migrated.init();
-      expect(migrated.getSchemaVersion()).toBe(97);
+      expect(migrated.getSchemaVersion()).toBe(98);
      const rows = migrated.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
      const names = new Set(rows.map((row) => row.name));
      expect(names.has("tokenBudgetSoftAlertedAt")).toBe(true);
@@ -2808,7 +2808,7 @@ describe("migration v67 drops orphan project auth tables", () => {

      migrated = new Database(fusion);
      migrated.init();
-      expect(migrated.getSchemaVersion()).toBe(97);
+      expect(migrated.getSchemaVersion()).toBe(98);
      const tables = migrated
        .prepare("SELECT name FROM sqlite_master WHERE type='table' AND name LIKE 'project_auth_%'")
        .all() as Array<{ name: string }>;
@@ -2835,7 +2835,7 @@ describe("migration v67 drops orphan project auth tables", () => {

    try {
      fresh.init();
-      expect(fresh.getSchemaVersion()).toBe(97);
+      expect(fresh.getSchemaVersion()).toBe(98);
      const tables = fresh
        .prepare("SELECT name FROM sqlite_master WHERE type='table' AND name LIKE 'project_auth_%'")
        .all() as Array<{ name: string }>;
--- a/packages/core/src/tests/goals-schema.test.ts
+++ b/packages/core/src/tests/goals-schema.test.ts
@@ -91,6 +91,6 @@ describe("goals schema", () => {
  });

  it("reports schema version 92", () => {
-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);
  });
 });
--- a/packages/core/src/tests/insight-store.test.ts
+++ b/packages/core/src/tests/insight-store.test.ts
@@ -1000,7 +1000,7 @@ describe("Migration: pre-33 DB upgrade", () => {
      // Step 1: Create a fresh database at v33 (runs all migrations up to 33)
      const db1 = createDatabase(legacyDir);
      db1.init();
-      expect(db1.getSchemaVersion()).toBe(97);
+      expect(db1.getSchemaVersion()).toBe(98);
      db1.close();

      // Step 2: Manually downgrade to version 32 and drop insight tables
@@ -1035,7 +1035,7 @@ describe("Migration: pre-33 DB upgrade", () => {
      expect(tableNamesBefore).not.toContain("project_insight_runs");
      // Now run init — this triggers the v32→v33 migration
      db3.init();
-      expect(db3.getSchemaVersion()).toBe(97);
+      expect(db3.getSchemaVersion()).toBe(98);

      // Step 4: Verify insight tables exist after migration
      const tablesAfter = db3.prepare(
@@ -1066,12 +1066,12 @@ describe("Migration: pre-33 DB upgrade", () => {
    try {
      const db1 = createDatabase(testDir);
      db1.init();
-      expect(db1.getSchemaVersion()).toBe(97);
+      expect(db1.getSchemaVersion()).toBe(98);
      db1.close();

      const db2 = createDatabase(testDir);
      expect(() => db2.init()).not.toThrow();
-      expect(db2.getSchemaVersion()).toBe(97);
+      expect(db2.getSchemaVersion()).toBe(98);
      db2.close();
    } finally {
      rmSync(testDir, { recursive: true, force: true });
@@ -1085,7 +1085,7 @@ describe("Migration: pre-33 DB upgrade", () => {
      // Step 1: Create a fresh DB and run migrations
      const db1 = createDatabase(compatDir);
      db1.init();
-      expect(db1.getSchemaVersion()).toBe(97);
+      expect(db1.getSchemaVersion()).toBe(98);

      // Step 2: Strip lifecycle and cancelledAt columns by recreating the
      // table without them. This simulates a DB that was created before the
--- a/packages/core/src/tests/mission-store.test.ts
+++ b/packages/core/src/tests/mission-store.test.ts
@@ -97,6 +97,35 @@ describe("MissionStore", () => {
      expect(list[2].id).toBe(m1.id);
    });

+    it("round-trips mission branchStrategy on create", () => {
+      const mission = store.createMission({
+        title: "Branch strategy",
+        branchStrategy: { mode: "custom-new", branchName: "feature/mission" },
+      });
+
+      const fetched = store.getMission(mission.id);
+      expect(fetched?.branchStrategy).toEqual({ mode: "custom-new", branchName: "feature/mission" });
+    });
+
+    it("updates mission branchStrategy", () => {
+      const mission = store.createMission({ title: "Original" });
+      const updated = store.updateMission(mission.id, {
+        branchStrategy: { mode: "auto-per-task" },
+      });
+
+      expect(updated.branchStrategy).toEqual({ mode: "auto-per-task" });
+      expect(store.getMission(mission.id)?.branchStrategy).toEqual({ mode: "auto-per-task" });
+    });
+
+    it("reads undefined branchStrategy for legacy and corrupt rows", () => {
+      const mission = store.createMission({ title: "Legacy row" });
+      db.prepare("UPDATE missions SET branchStrategy = NULL WHERE id = ?").run(mission.id);
+      expect(store.getMission(mission.id)?.branchStrategy).toBeUndefined();
+
+      db.prepare("UPDATE missions SET branchStrategy = ? WHERE id = ?").run("{not-json", mission.id);
+      expect(store.getMission(mission.id)?.branchStrategy).toBeUndefined();
+    });
+
    it("updates a mission", async () => {
      const mission = store.createMission({ title: "Original" });
      await new Promise((r) => setTimeout(r, 5)); // Ensure timestamp difference
@@ -1901,6 +1930,62 @@ describe("MissionStore", () => {
      expect(task?.baseBranch).toBe("release/1.0");
    });

+    it("uses mission branchStrategy auto-per-task when branch options are omitted", async () => {
+      const { TaskStore } = await import("../store.js");
+      const ts = new TaskStore(tmpDir, join(tmpDir, ".fusion-global-settings"), { inMemoryDb: true });
+      const msWithTs = ts.getMissionStore();
+
+      const mission = msWithTs.createMission({ title: "Mission", branchStrategy: { mode: "auto-per-task" } });
+      const milestone = msWithTs.addMilestone(mission.id, { title: "Milestone" });
+      const slice = msWithTs.addSlice(milestone.id, { title: "Slice" });
+      const feature = msWithTs.addFeature(slice.id, { title: "Original" });
+
+      const triaged = await msWithTs.triageFeature(feature.id);
+      const task = await ts.getTask(triaged.taskId!);
+
+      expect(task?.branchContext?.assignmentMode).toBe("per-task-derived");
+    });
+
+    it("uses mission branchStrategy existing branch when branch options are omitted", async () => {
+      const { TaskStore } = await import("../store.js");
+      const ts = new TaskStore(tmpDir, join(tmpDir, ".fusion-global-settings"), { inMemoryDb: true });
+      const msWithTs = ts.getMissionStore();
+
+      const mission = msWithTs.createMission({
+        title: "Mission",
+        branchStrategy: { mode: "existing", branchName: "release/shared" },
+      });
+      const milestone = msWithTs.addMilestone(mission.id, { title: "Milestone" });
+      const slice = msWithTs.addSlice(milestone.id, { title: "Slice" });
+      const feature = msWithTs.addFeature(slice.id, { title: "Original" });
+
+      const triaged = await msWithTs.triageFeature(feature.id);
+      const task = await ts.getTask(triaged.taskId!);
+
+      expect(task?.branch).toBe("release/shared");
+      expect(task?.branchContext?.assignmentMode).toBe("shared");
+    });
+
+    it("explicit branch options override mission branchStrategy defaults", async () => {
+      const { TaskStore } = await import("../store.js");
+      const ts = new TaskStore(tmpDir, join(tmpDir, ".fusion-global-settings"), { inMemoryDb: true });
+      const msWithTs = ts.getMissionStore();
+
+      const mission = msWithTs.createMission({ title: "Mission", branchStrategy: { mode: "auto-per-task" } });
+      const milestone = msWithTs.addMilestone(mission.id, { title: "Milestone" });
+      const slice = msWithTs.addSlice(milestone.id, { title: "Slice" });
+      const feature = msWithTs.addFeature(slice.id, { title: "Original" });
+
+      const triaged = await msWithTs.triageFeature(feature.id, undefined, undefined, {
+        branch: "hotfix/shared",
+        assignmentMode: "shared",
+      });
+      const task = await ts.getTask(triaged.taskId!);
+
+      expect(task?.branch).toBe("hotfix/shared");
+      expect(task?.branchContext?.assignmentMode).toBe("shared");
+    });
+
    it("uses provided title and description overrides", async () => {
      const { TaskStore } = await import("../store.js");
      const ts = new TaskStore(tmpDir, join(tmpDir, ".fusion-global-settings"), { inMemoryDb: true });
@@ -2080,6 +2165,52 @@ describe("MissionStore", () => {
      expect(task?.baseBranch).toBe("develop");
    });

+    it("triageSlice uses mission auto-per-task branchStrategy defaults", async () => {
+      const { TaskStore } = await import("../store.js");
+      const ts = new TaskStore(tmpDir, join(tmpDir, ".fusion-global-settings"), { inMemoryDb: true });
+      const msWithTs = ts.getMissionStore();
+
+      const mission = msWithTs.createMission({
+        title: "Mission",
+        branchStrategy: { mode: "auto-per-task" },
+      });
+      const milestone = msWithTs.addMilestone(mission.id, { title: "Milestone" });
+      const slice = msWithTs.addSlice(milestone.id, { title: "Slice" });
+      const f1 = msWithTs.addFeature(slice.id, { title: "Feature 1" });
+
+      const triaged = await msWithTs.triageSlice(slice.id);
+      const task = await ts.getTask(triaged[0].taskId!);
+
+      expect(triaged[0].id).toBe(f1.id);
+      expect(task?.branchContext?.assignmentMode).toBe("per-task-derived");
+    });
+
+    it("triageSlice respects explicit branch options over mission strategy defaults", async () => {
+      const { TaskStore } = await import("../store.js");
+      const ts = new TaskStore(tmpDir, join(tmpDir, ".fusion-global-settings"), { inMemoryDb: true });
+      const msWithTs = ts.getMissionStore();
+
+      const mission = msWithTs.createMission({
+        title: "Mission",
+        baseBranch: "develop",
+        branchStrategy: { mode: "auto-per-task" },
+      });
+      const milestone = msWithTs.addMilestone(mission.id, { title: "Milestone" });
+      const slice = msWithTs.addSlice(milestone.id, { title: "Slice" });
+      msWithTs.addFeature(slice.id, { title: "Feature 1" });
+
+      const triaged = await msWithTs.triageSlice(slice.id, {
+        branch: "feature/manual",
+        assignmentMode: "shared",
+        baseBranch: "release",
+      });
+      const task = await ts.getTask(triaged[0].taskId!);
+
+      expect(task?.branch).toBe("feature/manual");
+      expect(task?.baseBranch).toBe("release");
+      expect(task?.branchContext?.assignmentMode).toBe("shared");
+    });
+
    it("triageSlice does not inject baseBranch when mission has none", async () => {
      const { TaskStore } = await import("../store.js");
      const ts = new TaskStore(tmpDir, join(tmpDir, ".fusion-global-settings"), { inMemoryDb: true });
@@ -2159,6 +2290,21 @@ describe("MissionStore", () => {
      expect(task2!.missionId).toBe(mission.id);
    });

+    it("auto-triage uses mission branchStrategy defaults", async () => {
+      const { ts, ms } = await createStoreWithTaskStore();
+
+      const mission = ms.createMission({ title: "Mission", branchStrategy: { mode: "auto-per-task" } });
+      ms.updateMission(mission.id, { autoAdvance: true });
+      const milestone = ms.addMilestone(mission.id, { title: "Milestone" });
+      const slice = ms.addSlice(milestone.id, { title: "Slice" });
+      const feature = ms.addFeature(slice.id, { title: "Feature 1" });
+
+      await ms.activateSlice(slice.id);
+
+      const task = await ts.getTask(ms.getFeature(feature.id)!.taskId!);
+      expect(task?.branchContext?.assignmentMode).toBe("per-task-derived");
+    });
+
    it("does not triage features when autoAdvance is false", async () => {
      const { ms } = await createStoreWithTaskStore();

@@ -3036,7 +3182,7 @@ describe("MissionStore", () => {

  describe("Loop State & Validator Run Schema (v31)", () => {
    it("schema version is 40 after migration", () => {
-      expect(db.getSchemaVersion()).toBe(97);
+      expect(db.getSchemaVersion()).toBe(98);
    });

    it("mission_features table has loop state columns", () => {
--- a/packages/core/src/tests/run-audit.test.ts
+++ b/packages/core/src/tests/run-audit.test.ts
@@ -584,7 +584,7 @@ describe("Run Audit", () => {
    });

    it("schema version is bumped to 40", () => {
-      expect(db.getSchemaVersion()).toBe(97);
+      expect(db.getSchemaVersion()).toBe(98);
    });
  });
 });
--- a/packages/core/src/tests/secrets-schema.test.ts
+++ b/packages/core/src/tests/secrets-schema.test.ts
@@ -42,7 +42,7 @@ describe("secrets schema migrations", () => {
      const version = db
        .prepare("SELECT value FROM __meta WHERE key = 'schemaVersion'")
        .get() as { value: string };
-      expect(version.value).toBe("97");
+      expect(version.value).toBe("98");
    } finally {
      db.close();
      rmSync(dir, { recursive: true, force: true });
@@ -105,7 +105,7 @@ describe("secrets schema migrations", () => {
      const version = db
        .prepare("SELECT value FROM __meta WHERE key = 'schemaVersion'")
        .get() as { value: string };
-      expect(version.value).toBe("97");
+      expect(version.value).toBe("98");
    } finally {
      db.close();
      rmSync(dir, { recursive: true, force: true });
@@ -155,7 +155,7 @@ describe("secrets schema migrations", () => {
        .prepare("SELECT value FROM __meta WHERE key = 'schemaVersion'")
        .get() as { value: string };

-      expect(projectVersion.value).toBe("97");
+      expect(projectVersion.value).toBe("98");
      expect(centralVersion.value).toBe("13");
    } finally {
      projectDb.close();
--- a/packages/core/src/tests/store-merge-queue.test.ts
+++ b/packages/core/src/tests/store-merge-queue.test.ts
@@ -60,7 +60,7 @@ describe("TaskStore merge queue", () => {
      expect.arrayContaining(["idx_mergeQueue_lease_ready", "idx_mergeQueue_leaseExpiresAt"]),
    );

-    expect(store.getDatabase().getSchemaVersion()).toBe(97);
+    expect(store.getDatabase().getSchemaVersion()).toBe(98);
  });

  it("migrates a legacy v88 database and preserves task rows", async () => {
--- a/packages/core/src/tests/task-documents.test.ts
+++ b/packages/core/src/tests/task-documents.test.ts
@@ -51,7 +51,7 @@ describe("TaskStore task documents", () => {

    expect(tableNames.has("task_documents")).toBe(true);
    expect(tableNames.has("task_document_revisions")).toBe(true);
-    expect(db.getSchemaVersion()).toBe(97);
+    expect(db.getSchemaVersion()).toBe(98);

    const index = db
      .prepare(
--- a/packages/core/src/db.ts
+++ b/packages/core/src/db.ts
@@ -149,7 +149,7 @@ export function probeFts5(db: DatabaseSync): boolean {

 // ── Schema Definition ────────────────────────────────────────────────

-const SCHEMA_VERSION = 97;
+const SCHEMA_VERSION = 98;

 function normalizeTaskComments(
  steeringComments: SteeringComment[] | undefined,
@@ -758,6 +758,7 @@ CREATE TABLE IF NOT EXISTS missions (
  status TEXT NOT NULL,
  interviewState TEXT NOT NULL,
  baseBranch TEXT,
+  branchStrategy TEXT,
  autoAdvance INTEGER DEFAULT 0,
  autoMerge INTEGER,
  createdAt TEXT NOT NULL,
@@ -3719,6 +3720,12 @@ export class Database {
      });
    }

+    if (version < 98) {
+      this.applyMigration(98, () => {
+        this.addColumnIfMissing("missions", "branchStrategy", "TEXT");
+      });
+    }
+
  }

  /**
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -675,6 +675,7 @@ export type {
  MissionEventType,
  AutopilotStatus,
  Mission,
+  MissionBranchStrategy,
  Milestone,
  Slice,
  MissionFeature,
--- a/packages/core/src/mission-store.ts
+++ b/packages/core/src/mission-store.ts
@@ -16,6 +16,7 @@ import type { Database } from "./db.js";
 import { fromJson, toJson, toJsonNullable } from "./db.js";
 import type {
  Mission,
+  MissionBranchStrategy,
  Milestone,
  Slice,
  MissionFeature,
@@ -63,6 +64,22 @@ import { reconcileDeterministicDuplicate, runDeterministicDuplicateGuard } from
 */
 const DEFAULT_IMPLEMENTATION_RETRY_BUDGET = 3;

+function missionBranchStrategyDefaults(strategy?: MissionBranchStrategy): {
+  branch?: string;
+  assignmentMode: "shared" | "per-task-derived";
+} {
+  if (!strategy) {
+    return { assignmentMode: "shared" };
+  }
+  if (strategy.mode === "auto-per-task") {
+    return { assignmentMode: "per-task-derived" };
+  }
+  if ((strategy.mode === "existing" || strategy.mode === "custom-new") && strategy.branchName?.trim()) {
+    return { branch: strategy.branchName.trim(), assignmentMode: "shared" };
+  }
+  return { assignmentMode: "shared" };
+}
+
 export function deriveMilestoneAcceptanceCriteriaFromFeatures(features: MissionFeature[]): string | undefined {
  const lines = features
    .map((feature) => {
@@ -189,6 +206,7 @@ interface MissionRow {
  status: string;
  interviewState: string;
  baseBranch: string | null;
+  branchStrategy: string | null;
  autoMerge: number | null;
  autoAdvance: number;
  autopilotEnabled: number;
@@ -356,6 +374,15 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
   * Convert a database row to a Mission object.
   */
  private rowToMission(row: MissionRow): Mission {
+    let branchStrategy: MissionBranchStrategy | undefined;
+    if (row.branchStrategy) {
+      try {
+        branchStrategy = JSON.parse(row.branchStrategy) as MissionBranchStrategy;
+      } catch {
+        branchStrategy = undefined;
+      }
+    }
+
    return {
      id: row.id,
      title: row.title,
@@ -363,6 +390,7 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
      status: row.status as MissionStatus,
      interviewState: row.interviewState as InterviewState,
      baseBranch: row.baseBranch || undefined,
+      branchStrategy,
      autoMerge: row.autoMerge === null ? undefined : Boolean(row.autoMerge),
      autoAdvance: Boolean(row.autoAdvance),
      autopilotEnabled: Boolean(row.autopilotEnabled),
@@ -555,6 +583,7 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
      status: "planning",
      interviewState: "not_started",
      baseBranch: input.baseBranch,
+      branchStrategy: input.branchStrategy,
      autoMerge: input.autoMerge,
      autoAdvance: false,
      autopilotEnabled: input.autopilotEnabled ?? false,
@@ -564,8 +593,8 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
    };

    this.db.prepare(`
-      INSERT INTO missions (id, title, description, status, interviewState, baseBranch, autoMerge, autoAdvance, autopilotEnabled, autopilotState, createdAt, updatedAt)
-      VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+      INSERT INTO missions (id, title, description, status, interviewState, baseBranch, branchStrategy, autoMerge, autoAdvance, autopilotEnabled, autopilotState, createdAt, updatedAt)
+      VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
    `).run(
      mission.id,
      mission.title,
@@ -573,6 +602,7 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
      mission.status,
      mission.interviewState,
      mission.baseBranch ?? null,
+      mission.branchStrategy ? JSON.stringify(mission.branchStrategy) : null,
      mission.autoMerge === undefined ? null : (mission.autoMerge ? 1 : 0),
      mission.autoAdvance ? 1 : 0,
      mission.autopilotEnabled ? 1 : 0,
@@ -1126,6 +1156,7 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
        status = ?,
        interviewState = ?,
        baseBranch = ?,
+        branchStrategy = ?,
        autoMerge = ?,
        autoAdvance = ?,
        autopilotEnabled = ?,
@@ -1139,6 +1170,7 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
      updated.status,
      updated.interviewState,
      updated.baseBranch ?? null,
+      updated.branchStrategy ? JSON.stringify(updated.branchStrategy) : null,
      updated.autoMerge === undefined ? null : (updated.autoMerge ? 1 : 0),
      updated.autoAdvance ? 1 : 0,
      updated.autopilotEnabled ? 1 : 0,
@@ -3305,7 +3337,10 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
    const milestone = slice ? this.getMilestone(slice.milestoneId) : undefined;
    const missionId = milestone?.missionId;
    const mission = missionId ? this.getMission(missionId) : undefined;
+    const strategyDefaults = missionBranchStrategyDefaults(mission?.branchStrategy);
    const resolvedBaseBranch = branchOptions?.baseBranch ?? mission?.baseBranch;
+    const resolvedBranch = branchOptions?.branch ?? strategyDefaults.branch;
+    const resolvedAssignmentMode = branchOptions?.assignmentMode ?? strategyDefaults.assignmentMode;

    const lockScope = missionId ? `mission:${missionId}` : `mission-store:${this.taskStore.getRootDir()}`;
    const guard = await runDeterministicDuplicateGuard(this.taskStore, {
@@ -3321,14 +3356,14 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
        const createdTask = await this.taskStore.createTask({
          title: taskTitle || feature.title,
          description,
-          branch: branchOptions?.branch,
+          branch: resolvedBranch,
          baseBranch: resolvedBaseBranch,
          ...(missionId
            ? {
                branchContext: {
                  groupId: `mission:${missionId}`,
                  source: "mission" as const,
-                  assignmentMode: branchOptions?.assignmentMode ?? "shared",
+                  assignmentMode: resolvedAssignmentMode,
                  inheritedBaseBranch: resolvedBaseBranch,
                },
              }
@@ -3389,17 +3424,21 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
    const definedFeatures = features.filter((f) => f.status === "defined");
    const milestone = this.getMilestone(slice.milestoneId);
    const mission = milestone ? this.getMission(milestone.missionId) : undefined;
+    const strategyDefaults = missionBranchStrategyDefaults(mission?.branchStrategy);
    const resolvedBaseBranch = branchOptions?.baseBranch ?? mission?.baseBranch;
+    const resolvedAssignmentMode = branchOptions?.assignmentMode ?? strategyDefaults.assignmentMode;
+    const resolvedBranch = branchOptions?.branch ?? strategyDefaults.branch;

    const triaged: MissionFeature[] = [];
    for (const feature of definedFeatures) {
-      const branch = branchOptions?.assignmentMode === "per-task-derived"
-        ? (branchOptions?.branch ? `${branchOptions.branch}/${feature.id.toLowerCase()}` : undefined)
-        : branchOptions?.branch;
+      const strategyBranch = resolvedAssignmentMode === "per-task-derived"
+        ? (resolvedBranch ? `${resolvedBranch}/${feature.id.toLowerCase()}` : undefined)
+        : resolvedBranch;
      const updated = await this.triageFeature(feature.id, undefined, undefined, {
-        ...branchOptions,
-        branch,
+        branch: strategyBranch,
        baseBranch: resolvedBaseBranch,
+        assignmentMode: resolvedAssignmentMode,
+        ...branchOptions,
      });
      triaged.push(updated);
    }
@@ -3589,13 +3628,14 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
    let applied = 0;

    for (const mission of snapshot.payload.missions) {
-      this.db.prepare(`INSERT INTO missions (id, title, description, status, interviewState, autoMerge, autoAdvance, autopilotEnabled, autopilotState, lastAutopilotActivityAt, createdAt, updatedAt)
-        VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+      this.db.prepare(`INSERT INTO missions (id, title, description, status, interviewState, baseBranch, branchStrategy, autoMerge, autoAdvance, autopilotEnabled, autopilotState, lastAutopilotActivityAt, createdAt, updatedAt)
+        VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
        ON CONFLICT(id) DO UPDATE SET
          title=excluded.title, description=excluded.description, status=excluded.status, interviewState=excluded.interviewState,
-          autoMerge=excluded.autoMerge, autoAdvance=excluded.autoAdvance, autopilotEnabled=excluded.autopilotEnabled, autopilotState=excluded.autopilotState,
+          baseBranch=excluded.baseBranch, branchStrategy=excluded.branchStrategy, autoMerge=excluded.autoMerge, autoAdvance=excluded.autoAdvance, autopilotEnabled=excluded.autopilotEnabled, autopilotState=excluded.autopilotState,
          lastAutopilotActivityAt=excluded.lastAutopilotActivityAt, updatedAt=excluded.updatedAt`).run(
        mission.id, mission.title, mission.description ?? null, mission.status, mission.interviewState,
+        mission.baseBranch ?? null, mission.branchStrategy ? JSON.stringify(mission.branchStrategy) : null,
        mission.autoMerge === undefined ? null : (mission.autoMerge ? 1 : 0), mission.autoAdvance ? 1 : 0,
        mission.autopilotEnabled ? 1 : 0, mission.autopilotState, mission.lastAutopilotActivityAt ?? null, mission.createdAt, mission.updatedAt,
      );
--- a/packages/core/src/mission-types.ts
+++ b/packages/core/src/mission-types.ts
@@ -113,6 +113,11 @@ export interface MissionHealth {
 * A Mission represents a high-level objective or project.
 * Missions contain milestones that break down the work into phases.
 */
+export type MissionBranchStrategy = {
+  mode: "project-default" | "existing" | "custom-new" | "auto-per-task";
+  branchName?: string;
+};
+
 export interface Mission {
  /** Unique identifier (e.g., "M-LZ7DN0-A2B5") */
  id: string;
@@ -124,6 +129,8 @@ export interface Mission {
  status: MissionStatus;
  /** Optional integration base branch inherited by triaged feature tasks */
  baseBranch?: string;
+  /** Mission triage branch strategy: auto-per-task => assignmentMode "per-task-derived"; existing/custom-new => shared branchName; project-default/absent => shared default behavior. */
+  branchStrategy?: MissionBranchStrategy;
  /** State of the AI specification interview process */
  interviewState: InterviewState;
  /**
@@ -375,6 +382,8 @@ export interface MissionCreateInput {
  description?: string;
  /** Optional integration base branch for tasks created from this mission */
  baseBranch?: string;
+  /** Optional branch strategy applied as the default for mission triage operations. */
+  branchStrategy?: MissionBranchStrategy;
  /** Optional mission-level auto-merge override for linked task branches. */
  autoMerge?: boolean;
 }
--- a/packages/dashboard/app/api/legacy.ts
+++ b/packages/dashboard/app/api/legacy.ts
@@ -3426,10 +3426,25 @@ export function createTasksFromPlanning(
  planningSessionId: string,
  subtasks: PlanningSubtaskDraft[],
  projectId?: string,
+  options?: {
+    branchSelection?: {
+      mode: "project-default" | "auto-new" | "existing" | "custom-new";
+      branchName?: string;
+      baseBranch?: string;
+    };
+    branchAssignment?: {
+      mode: "shared" | "per-task-derived";
+    };
+  },
 ): Promise<{ tasks: Task[] }> {
  return api<{ tasks: Task[] }>(withProjectId("/planning/create-tasks", projectId), {
    method: "POST",
-    body: JSON.stringify({ planningSessionId, subtasks }),
+    body: JSON.stringify({
+      planningSessionId,
+      subtasks,
+      ...(options?.branchSelection ? { branchSelection: options.branchSelection } : {}),
+      ...(options?.branchAssignment ? { branchAssignment: options.branchAssignment } : {}),
+    }),
  });
 }

@@ -6803,6 +6818,10 @@ export interface Mission {
  title: string;
  description?: string;
  baseBranch?: string;
+  branchStrategy?: {
+    mode: "project-default" | "existing" | "custom-new" | "auto-per-task";
+    branchName?: string;
+  };
  status: MissionStatus;
  interviewState: "not_started" | "in_progress" | "completed" | "needs_update";
  autoAdvance?: boolean;
@@ -6890,7 +6909,7 @@ export function fetchMissions(projectId?: string): Promise<MissionWithSummary[]>
 }

 /** Create a new mission */
-export function createMission(input: { title: string; description?: string; autoAdvance?: boolean; autopilotEnabled?: boolean; baseBranch?: string }, projectId?: string): Promise<Mission> {
+export function createMission(input: { title: string; description?: string; autoAdvance?: boolean; autopilotEnabled?: boolean; baseBranch?: string; branchStrategy?: Mission["branchStrategy"] }, projectId?: string): Promise<Mission> {
  return api<Mission>(withProjectId("/missions", projectId), {
    method: "POST",
    body: JSON.stringify(input),
--- a/packages/dashboard/app/components/MissionManager.tsx
+++ b/packages/dashboard/app/components/MissionManager.tsx
@@ -250,12 +250,20 @@ function formatValidationState(state?: string): string {
 }

 // Form types
+type MissionBranchStrategyMode = "project-default" | "existing" | "custom-new" | "auto-per-task";
+
+interface MissionBranchStrategy {
+  mode: MissionBranchStrategyMode;
+  branchName?: string;
+}
+
 interface MissionFormData {
  title: string;
  description: string;
  status: MissionStatus;
  autopilotEnabled: boolean;
  baseBranch: string;
+  branchStrategy: MissionBranchStrategy;
 }

 interface MilestoneFormData {
@@ -285,6 +293,9 @@ const EMPTY_MISSION_FORM: MissionFormData = {
  status: "planning",
  autopilotEnabled: false,
  baseBranch: "",
+  branchStrategy: {
+    mode: "project-default",
+  },
 };

 const EMPTY_MILESTONE_FORM: MilestoneFormData = {
@@ -308,6 +319,53 @@ const EMPTY_FEATURE_FORM: FeatureFormData = {
  status: "defined",
 };

+function normalizeMissionBranchStrategy(strategy?: Mission["branchStrategy"]): MissionBranchStrategy {
+  if (!strategy) {
+    return { mode: "project-default" };
+  }
+
+  if (strategy.mode === "existing" || strategy.mode === "custom-new") {
+    return {
+      mode: strategy.mode,
+      branchName: strategy.branchName ?? "",
+    };
+  }
+
+  if (strategy.mode === "auto-per-task") {
+    return { mode: "auto-per-task" };
+  }
+
+  return { mode: "project-default" };
+}
+
+function toMissionBranchOptions(mission?: Mission): Parameters<typeof triageFeature>[4] | undefined {
+  if (!mission?.baseBranch && !mission?.branchStrategy) {
+    return undefined;
+  }
+
+  const strategy = mission.branchStrategy;
+  const branchSelection: NonNullable<Parameters<typeof triageFeature>[4]>["branchSelection"] = {
+    mode: "project-default",
+    ...(mission.baseBranch ? { baseBranch: mission.baseBranch } : {}),
+  };
+  const options: NonNullable<Parameters<typeof triageFeature>[4]> = { branchSelection };
+
+  if (strategy?.mode === "existing" || strategy?.mode === "custom-new") {
+    const branchName = strategy.branchName?.trim();
+    if (branchName) {
+      options.branchSelection = {
+        mode: strategy.mode,
+        branchName,
+        ...(mission.baseBranch ? { baseBranch: mission.baseBranch } : {}),
+      };
+    }
+  } else if (strategy?.mode === "auto-per-task") {
+    options.branchAssignment = { mode: "per-task-derived" };
+  }
+
+  return options;
+}
+
 type MissionHealthState = "healthy" | "warning" | "error";

 const HOUR_MS = 60 * 60 * 1000;
@@ -1420,6 +1478,7 @@ export function MissionManager({ isOpen, isInline = false, onClose, addToast, pr
      status: mission.status,
      autopilotEnabled: mission.autopilotEnabled ?? false,
      baseBranch: mission.baseBranch ?? "",
+      branchStrategy: normalizeMissionBranchStrategy(mission.branchStrategy),
    });
  }, []);

@@ -1435,6 +1494,19 @@ export function MissionManager({ isOpen, isInline = false, onClose, addToast, pr
      return;
    }

+    const branchNameRequired =
+      missionForm.branchStrategy.mode === "existing" || missionForm.branchStrategy.mode === "custom-new";
+    const branchName = missionForm.branchStrategy.branchName?.trim() ?? "";
+    if (branchNameRequired && !branchName) {
+      addToast("Branch name is required for selected branch strategy", "error");
+      return;
+    }
+
+    const branchStrategy: Mission["branchStrategy"] =
+      missionForm.branchStrategy.mode === "existing" || missionForm.branchStrategy.mode === "custom-new"
+        ? { mode: missionForm.branchStrategy.mode, branchName }
+        : { mode: missionForm.branchStrategy.mode };
+
    try {
      setSaving(true);
      if (isCreatingMission) {
@@ -1442,6 +1514,8 @@ export function MissionManager({ isOpen, isInline = false, onClose, addToast, pr
          title: missionForm.title.trim(),
          description: missionForm.description.trim() || undefined,
          autopilotEnabled: missionForm.autopilotEnabled,
+          baseBranch: missionForm.baseBranch.trim() || undefined,
+          branchStrategy,
        }, projectId);
        addToast("Mission created", "success");
      } else if (editingMissionId) {
@@ -1453,6 +1527,7 @@ export function MissionManager({ isOpen, isInline = false, onClose, addToast, pr
          status: missionForm.status,
          autopilotEnabled: missionForm.autopilotEnabled,
          baseBranch: missionForm.baseBranch.trim() || "",
+          branchStrategy,
        };
        if (missionForm.autopilotEnabled) {
          updates.autoAdvance = true;
@@ -1778,14 +1853,7 @@ export function MissionManager({ isOpen, isInline = false, onClose, addToast, pr
  const handleTriageFeature = useCallback(async (featureId: string) => {
    try {
      setSaving(true);
-      await triageFeature(featureId, undefined, undefined, projectId, selectedMission?.baseBranch
-        ? {
-            branchSelection: {
-              mode: "project-default",
-              baseBranch: selectedMission.baseBranch,
-            },
-          }
-        : undefined);
+      await triageFeature(featureId, undefined, undefined, projectId, toMissionBranchOptions(selectedMission ?? undefined));
      addToast("Feature triaged — task created", "success");
      await loadMissionDetail(selectedMission!.id);
    } catch (err) {
@@ -1825,14 +1893,7 @@ export function MissionManager({ isOpen, isInline = false, onClose, addToast, pr
  const handleTriageAllSliceFeatures = useCallback(async (sliceId: string) => {
    try {
      setSaving(true);
-      const result = await triageAllSliceFeatures(sliceId, projectId, selectedMission?.baseBranch
-        ? {
-            branchSelection: {
-              mode: "project-default",
-              baseBranch: selectedMission.baseBranch,
-            },
-          }
-        : undefined);
+      const result = await triageAllSliceFeatures(sliceId, projectId, toMissionBranchOptions(selectedMission ?? undefined));
      addToast(`Triaged ${result.count} feature${result.count !== 1 ? "s" : ""}`, "success");
      await loadMissionDetail(selectedMission!.id);
    } catch (err) {
@@ -2460,6 +2521,47 @@ export function MissionManager({ isOpen, isInline = false, onClose, addToast, pr
                      aria-label="Mission target branch"
                    />
                  </label>
+                  <label>
+                    Branch strategy
+                    <select
+                      value={missionForm.branchStrategy.mode}
+                      onChange={(e) =>
+                        setMissionForm({
+                          ...missionForm,
+                          branchStrategy: {
+                            mode: e.target.value as MissionBranchStrategyMode,
+                            branchName: missionForm.branchStrategy.branchName,
+                          },
+                        })
+                      }
+                      aria-label="Mission branch strategy"
+                    >
+                      <option value="project-default">Use project/default branch</option>
+                      <option value="auto-per-task">Auto-name a branch per task (from details)</option>
+                      <option value="existing">Use existing branch</option>
+                      <option value="custom-new">Create custom branch</option>
+                    </select>
+                  </label>
+                  {(missionForm.branchStrategy.mode === "existing" || missionForm.branchStrategy.mode === "custom-new") && (
+                    <label>
+                      Branch name
+                      <input
+                        type="text"
+                        placeholder="e.g. feature/mission-work"
+                        value={missionForm.branchStrategy.branchName ?? ""}
+                        onChange={(e) =>
+                          setMissionForm({
+                            ...missionForm,
+                            branchStrategy: {
+                              ...missionForm.branchStrategy,
+                              branchName: e.target.value,
+                            },
+                          })
+                        }
+                        aria-label="Mission branch name"
+                      />
+                    </label>
+                  )}
                  <div className="mission-form-card__row">
                    <select
                      value={missionForm.status}
@@ -4056,6 +4158,57 @@ export function MissionManager({ isOpen, isInline = false, onClose, addToast, pr
                    onChange={(e) => setMissionForm({ ...missionForm, description: e.target.value })}
                    rows={2}
                  />
+                  <label>
+                    Target branch
+                    <input
+                      type="text"
+                      placeholder="e.g. main"
+                      value={missionForm.baseBranch}
+                      onChange={(e) => setMissionForm({ ...missionForm, baseBranch: e.target.value })}
+                      aria-label="Mission target branch"
+                    />
+                  </label>
+                  <label>
+                    Branch strategy
+                    <select
+                      value={missionForm.branchStrategy.mode}
+                      onChange={(e) =>
+                        setMissionForm({
+                          ...missionForm,
+                          branchStrategy: {
+                            mode: e.target.value as MissionBranchStrategyMode,
+                            branchName: missionForm.branchStrategy.branchName,
+                          },
+                        })
+                      }
+                      aria-label="Mission branch strategy"
+                    >
+                      <option value="project-default">Use project/default branch</option>
+                      <option value="auto-per-task">Auto-name a branch per task (from details)</option>
+                      <option value="existing">Use existing branch</option>
+                      <option value="custom-new">Create custom branch</option>
+                    </select>
+                  </label>
+                  {(missionForm.branchStrategy.mode === "existing" || missionForm.branchStrategy.mode === "custom-new") && (
+                    <label>
+                      Branch name
+                      <input
+                        type="text"
+                        placeholder="e.g. feature/mission-work"
+                        value={missionForm.branchStrategy.branchName ?? ""}
+                        onChange={(e) =>
+                          setMissionForm({
+                            ...missionForm,
+                            branchStrategy: {
+                              ...missionForm.branchStrategy,
+                              branchName: e.target.value,
+                            },
+                          })
+                        }
+                        aria-label="Mission branch name"
+                      />
+                    </label>
+                  )}
                  <div className="mission-form-card__actions">
                    <button className="mission-btn mission-btn--primary" onClick={handleSaveMission} disabled={saving}>
                      {saving ? <Loader2 size={14} className="spinner" /> : <Check size={14} />}
@@ -4121,6 +4274,47 @@ export function MissionManager({ isOpen, isInline = false, onClose, addToast, pr
                      aria-label="Mission target branch"
                    />
                  </label>
+                  <label>
+                    Branch strategy
+                    <select
+                      value={missionForm.branchStrategy.mode}
+                      onChange={(e) =>
+                        setMissionForm({
+                          ...missionForm,
+                          branchStrategy: {
+                            mode: e.target.value as MissionBranchStrategyMode,
+                            branchName: missionForm.branchStrategy.branchName,
+                          },
+                        })
+                      }
+                      aria-label="Mission branch strategy"
+                    >
+                      <option value="project-default">Use project/default branch</option>
+                      <option value="auto-per-task">Auto-name a branch per task (from details)</option>
+                      <option value="existing">Use existing branch</option>
+                      <option value="custom-new">Create custom branch</option>
+                    </select>
+                  </label>
+                  {(missionForm.branchStrategy.mode === "existing" || missionForm.branchStrategy.mode === "custom-new") && (
+                    <label>
+                      Branch name
+                      <input
+                        type="text"
+                        placeholder="e.g. feature/mission-work"
+                        value={missionForm.branchStrategy.branchName ?? ""}
+                        onChange={(e) =>
+                          setMissionForm({
+                            ...missionForm,
+                            branchStrategy: {
+                              ...missionForm.branchStrategy,
+                              branchName: e.target.value,
+                            },
+                          })
+                        }
+                        aria-label="Mission branch name"
+                      />
+                    </label>
+                  )}
                  <div className="mission-form-card__row">
                    <select
                      value={missionForm.status}
--- a/packages/dashboard/app/components/PlanningModeModal.tsx
+++ b/packages/dashboard/app/components/PlanningModeModal.tsx
@@ -1643,6 +1643,13 @@ export function PlanningModeModal({ isOpen, onClose, onTaskCreated, onTasksCreat
          })),
        ),
        projectId,
+        {
+          branchSelection: {
+            mode: branchMode,
+            ...(branchMode === "existing" || branchMode === "custom-new" ? { branchName: branchName.trim() } : {}),
+            ...(baseBranch.trim() ? { baseBranch: baseBranch.trim() } : {}),
+          },
+        },
      );
      onTasksCreated(result.tasks);
      // Server cleans up the planning session after task creation; mirror that
@@ -1674,7 +1681,7 @@ export function PlanningModeModal({ isOpen, onClose, onTaskCreated, onTasksCreat
    } finally {
      setIsCreatingFromBreakdown(false);
    }
-  }, [broadcastCompleted, handleClose, view, onTasksCreated, projectId]);
+  }, [baseBranch, branchMode, branchName, broadcastCompleted, handleClose, view, onTasksCreated, projectId]);

  const handleBack = useCallback(async () => {
    if (view.type !== "question" || responseHistory.length === 0) {
--- a/packages/dashboard/app/components/tests/MissionManager.test.tsx
+++ b/packages/dashboard/app/components/tests/MissionManager.test.tsx
@@ -4703,6 +4703,106 @@ describe("MissionManager", () => {
    });
  });

+  describe("mission branch strategy controls", () => {
+    it("renders branch strategy selector and toggles branch-name input", async () => {
+      globalThis.fetch = createFetchMock();
+      render(<MissionManager isOpen={true} onClose={vi.fn()} addToast={vi.fn()} />);
+
+      await waitFor(() => {
+        expect(screen.getByText("Build Auth System")).toBeInTheDocument();
+      });
+
+      fireEvent.click(screen.getByText("Build Auth System"));
+      await waitForDetailLoaded();
+      fireEvent.click(screen.getByLabelText("Edit mission"));
+
+      const strategySelect = await screen.findByLabelText("Mission branch strategy");
+      expect(strategySelect).toBeInTheDocument();
+      expect(screen.queryByLabelText("Mission branch name")).toBeNull();
+
+      fireEvent.change(strategySelect, { target: { value: "existing" } });
+      expect(await screen.findByLabelText("Mission branch name")).toBeInTheDocument();
+    });
+
+    it("sends branch strategy and base branch on mission update", async () => {
+      const fetchSpy = vi.fn((input: RequestInfo | URL, init?: RequestInit) => {
+        const url = String(input);
+        if (url.includes("/api/missions/M-001") && init?.method === "PATCH") {
+          return Promise.resolve(mockApiResponse(mockMissionDetail));
+        }
+        return createFetchMock()(input, init);
+      });
+      globalThis.fetch = fetchSpy as unknown as typeof fetch;
+
+      render(<MissionManager isOpen={true} onClose={vi.fn()} addToast={vi.fn()} />);
+
+      await waitFor(() => {
+        expect(screen.getByText("Build Auth System")).toBeInTheDocument();
+      });
+
+      fireEvent.click(screen.getByText("Build Auth System"));
+      await waitForDetailLoaded();
+      fireEvent.click(screen.getByLabelText("Edit mission"));
+
+      fireEvent.change(screen.getByLabelText("Mission target branch"), { target: { value: "release/2026" } });
+      fireEvent.change(screen.getByLabelText("Mission branch strategy"), { target: { value: "custom-new" } });
+      fireEvent.change(await screen.findByLabelText("Mission branch name"), { target: { value: "feature/mission-custom" } });
+      fireEvent.click(screen.getByRole("button", { name: "Update" }));
+
+      await waitFor(() => {
+        const patchCall = fetchSpy.mock.calls.find(([input, init]) =>
+          String(input).includes("/api/missions/M-001") && init?.method === "PATCH",
+        );
+        expect(patchCall).toBeTruthy();
+        const body = JSON.parse(String(patchCall?.[1]?.body ?? "{}"));
+        expect(body.baseBranch).toBe("release/2026");
+        expect(body.branchStrategy).toEqual({ mode: "custom-new", branchName: "feature/mission-custom" });
+      });
+    });
+
+    it("maps mission branch strategy into triage branch options", async () => {
+      const triageMission = {
+        ...mockMissionDetail,
+        baseBranch: "main",
+        branchStrategy: { mode: "auto-per-task" as const },
+      };
+
+      globalThis.fetch = ((input: RequestInfo | URL) => {
+        const url = String(input);
+        if (url.includes("/api/missions/M-001") && !url.includes("/milestones") && !url.includes("/events") && !url.includes("/health")) {
+          return Promise.resolve(mockApiResponse(triageMission));
+        }
+        return createFetchMock()(input);
+      }) as unknown as typeof fetch;
+
+      render(<MissionManager isOpen={true} onClose={vi.fn()} addToast={vi.fn()} />);
+
+      await waitFor(() => {
+        expect(screen.getByText("Build Auth System")).toBeInTheDocument();
+      });
+      fireEvent.click(screen.getByText("Build Auth System"));
+      await waitForDetailLoaded();
+
+      mockPreviewEnrichedDescription.mockRejectedValueOnce(new Error("skip preview"));
+      fireEvent.click(screen.getByTitle("Triage — create task"));
+
+      await waitFor(() => {
+        expect(mockTriageFeature).toHaveBeenCalled();
+      });
+
+      expect(mockTriageFeature).toHaveBeenCalledWith(
+        "F-001",
+        undefined,
+        undefined,
+        undefined,
+        {
+          branchSelection: { mode: "project-default", baseBranch: "main" },
+          branchAssignment: { mode: "per-task-derived" },
+        },
+      );
+    });
+  });
+
  describe("MissionManager tokenized sizing regression", () => {
    it("does not retain targeted hardcoded px literals in MissionManager selectors", async () => {
      const css = await loadAllAppCssBaseOnly();
--- a/packages/dashboard/app/components/tests/PlanningModeModal.planning-flow.test.tsx
+++ b/packages/dashboard/app/components/tests/PlanningModeModal.planning-flow.test.tsx
@@ -1184,6 +1184,93 @@ describe("PlanningModeModal", () => {
      expect(screen.getByRole("textbox", { name: "Branch name" })).toBeDefined();
    });

+    it("forwards selected branchSelection when creating tasks from breakdown", async () => {
+      const resumedSummary: PlanningSummary = {
+        title: "Resume-branch-breakdown",
+        description: "Recovered summary for branch breakdown",
+        suggestedSize: "M",
+        suggestedDependencies: [],
+        keyDeliverables: ["Implement", "Verify"],
+      };
+
+      mockFetchAiSession.mockResolvedValueOnce({
+        id: "session-branch-breakdown",
+        type: "planning",
+        status: "complete",
+        title: "Resume-branch-breakdown",
+        inputPayload: JSON.stringify({ initialPlan: "Recover and create breakdown with branch controls" }),
+        conversationHistory: "[]",
+        currentQuestion: null,
+        result: JSON.stringify(resumedSummary),
+        thinkingOutput: "",
+        error: null,
+        projectId: null,
+        createdAt: "2026-01-01T00:00:00.000Z",
+        updatedAt: "2026-01-01T00:00:00.000Z",
+      });
+
+      mockStartPlanningBreakdown.mockResolvedValueOnce({
+        sessionId: "session-branch-breakdown",
+        subtasks: [
+          {
+            id: "subtask-1",
+            title: "First subtask",
+            description: "First description",
+            suggestedSize: "M",
+            dependsOn: [],
+          },
+        ],
+      });
+      mockCreateTasksFromPlanning.mockResolvedValueOnce({ tasks: [] });
+
+      render(
+        <PlanningModeModal
+          isOpen={true}
+          onClose={mockOnClose}
+          onTaskCreated={mockOnTaskCreated}
+          onTasksCreated={vi.fn()}
+          tasks={mockTasks}
+          resumeSessionId="session-branch-breakdown"
+        />
+      );
+
+      await waitFor(() => {
+        expect(screen.getByRole("button", { name: "Break into Tasks" })).toBeDefined();
+      });
+
+      const branchStrategy = screen.getByRole("combobox", { name: "Branch strategy" }) as HTMLSelectElement;
+      fireEvent.change(branchStrategy, { target: { value: "existing" } });
+      fireEvent.change(screen.getByRole("textbox", { name: "Branch name" }), {
+        target: { value: "feat/planning-branch" },
+      });
+      fireEvent.change(screen.getByRole("textbox", { name: "Merge target / base branch (optional)" }), {
+        target: { value: "develop" },
+      });
+
+      fireEvent.click(screen.getByRole("button", { name: "Break into Tasks" }));
+
+      await waitFor(() => {
+        expect(screen.getByRole("button", { name: "Create Tasks" })).toBeDefined();
+      });
+
+      fireEvent.click(screen.getByRole("button", { name: "Create Tasks" }));
+
+      await waitFor(() => {
+        expect(mockCreateTasksFromPlanning).toHaveBeenCalledWith(
+          "session-branch-breakdown",
+          [{ id: "subtask-1" }],
+          undefined,
+          {
+            branchSelection: {
+              mode: "existing",
+              branchName: "feat/planning-branch",
+              baseBranch: "develop",
+            },
+          },
+        );
+      });
+    });
+
    it("preserves per-subtask priority selections when creating tasks from breakdown", async () => {
      const resumedSummary: PlanningSummary = {
        title: "Resume-to-breakdown-priority",
@@ -1253,6 +1340,7 @@ describe("PlanningModeModal", () => {
          "session-breakdown-priority",
          [{ id: "subtask-1", priority: "urgent" }],
          undefined,
+          { branchSelection: { mode: "project-default" } },
        );
      });
    });
@@ -1342,6 +1430,7 @@ describe("PlanningModeModal", () => {
            { id: "subtask-2", description: "Edited second description" },
          ],
          undefined,
+          { branchSelection: { mode: "project-default" } },
        );
      });
    });
@@ -1429,6 +1518,7 @@ describe("PlanningModeModal", () => {
            },
          ],
          undefined,
+          { branchSelection: { mode: "project-default" } },
        );
      });
    });
@@ -1508,6 +1598,7 @@ describe("PlanningModeModal", () => {
          "session-breakdown-remove-subtask",
          [{ id: "subtask-1" }],
          undefined,
+          { branchSelection: { mode: "project-default" } },
        );
      });
    });
--- a/packages/dashboard/app/components/mission-types.ts
+++ b/packages/dashboard/app/components/mission-types.ts
@@ -51,6 +51,10 @@ export interface Mission {
  title: string;
  description?: string;
  baseBranch?: string;
+  branchStrategy?: {
+    mode: "project-default" | "existing" | "custom-new" | "auto-per-task";
+    branchName?: string;
+  };
  status: MissionStatus;
  interviewState: "not_started" | "in_progress" | "completed" | "needs_update";
  autoAdvance?: boolean;
--- a/packages/dashboard/src/tests/mission-e2e.test.ts
+++ b/packages/dashboard/src/tests/mission-e2e.test.ts
@@ -66,11 +66,13 @@ function createMockMissionStore() {
  const generateAssertionId = () => `CA-MOCK${(assertionCounter++).toString(36).toUpperCase()}-TST`;

  return {
-    createMission: vi.fn((input: { title: string; description?: string }) => {
+    createMission: vi.fn((input: { title: string; description?: string; baseBranch?: string; branchStrategy?: Mission["branchStrategy"] }) => {
      const mission: Mission = {
        id: generateMissionId(),
        title: input.title,
        description: input.description,
+        baseBranch: input.baseBranch,
+        branchStrategy: input.branchStrategy,
        status: "planning",
        interviewState: "not_started",
        autoAdvance: false,
@@ -747,6 +749,34 @@ describe("Mission API", () => {
      expect(res.body.baseBranch).toBe("develop");
    });

+    it("should persist branchStrategy when provided during creation", async () => {
+      const { app } = buildApp();
+
+      const res = await request(
+        app,
+        "POST",
+        "/api/missions",
+        JSON.stringify({ title: "Mission", branchStrategy: { mode: "custom-new", branchName: "feature/mission" } }),
+        { "content-type": "application/json" }
+      );
+
+      expect(res.status).toBe(201);
+      expect(res.body.branchStrategy).toEqual({ mode: "custom-new", branchName: "feature/mission" });
+    });
+
+    it("rejects invalid branchStrategy mode", async () => {
+      const { app } = buildApp();
+      const res = await request(
+        app,
+        "POST",
+        "/api/missions",
+        JSON.stringify({ title: "Mission", branchStrategy: { mode: "bad-mode" } }),
+        { "content-type": "application/json" },
+      );
+      expect(res.status).toBe(400);
+      expect(String(res.body.error)).toContain("branchStrategy.mode");
+    });
+
    it("should persist auto-advance when provided during creation", async () => {
      const { app, missionStore } = buildApp();

@@ -1035,6 +1065,23 @@ describe("Mission API", () => {
      expect(updated?.baseBranch).toBe("release/1.0");
    });

+    it("should update mission branchStrategy", async () => {
+      const { app, missionStore } = buildApp();
+      const mission = missionStore.createMission({ title: "Original Title" });
+
+      const res = await request(
+        app,
+        "PATCH",
+        `/api/missions/${mission.id}`,
+        JSON.stringify({ branchStrategy: { mode: "auto-per-task" } }),
+        { "content-type": "application/json" }
+      );
+
+      expect(res.status).toBe(200);
+      expect(res.body.branchStrategy).toEqual({ mode: "auto-per-task" });
+      expect(missionStore.getMission(mission.id)?.branchStrategy).toEqual({ mode: "auto-per-task" });
+    });
+
    it("should update mission title with generated-format ID", async () => {
      const { app, missionStore } = buildApp();
      const mission = missionStore.createMission({ title: "Original Title" });
--- a/packages/dashboard/src/mission-routes.ts
+++ b/packages/dashboard/src/mission-routes.ts
@@ -18,6 +18,7 @@ import { TaskStore, resolvePlanningSettingsModel } from "@fusion/core";
 import { getOrCreateProjectStore } from "./project-store-resolver.js";
 import type {
  Mission,
+  MissionBranchStrategy,
  Milestone,
  Slice,
  MissionFeature,
@@ -134,6 +135,38 @@ function validateBoolean(value: unknown, fieldName: string): boolean {
  return value;
 }

+function validateMissionBranchStrategy(value: unknown): MissionBranchStrategy | undefined {
+  if (value === undefined || value === null) return undefined;
+  if (typeof value !== "object") {
+    throw new Error("branchStrategy must be an object");
+  }
+  const input = value as Record<string, unknown>;
+  const mode = input.mode;
+  if (
+    mode !== "project-default" &&
+    mode !== "existing" &&
+    mode !== "custom-new" &&
+    mode !== "auto-per-task"
+  ) {
+    throw new Error("branchStrategy.mode must be one of: project-default, existing, custom-new, auto-per-task");
+  }
+  const branchName = input.branchName;
+  if (branchName !== undefined && typeof branchName !== "string") {
+    throw new Error("branchStrategy.branchName must be a string when provided");
+  }
+  const trimmedBranchName = branchName?.trim();
+  if ((mode === "existing" || mode === "custom-new") && !trimmedBranchName) {
+    throw new Error("branchStrategy.branchName is required for existing/custom-new");
+  }
+  if (mode === "project-default" || mode === "auto-per-task") {
+    return { mode };
+  }
+  return {
+    mode,
+    branchName: trimmedBranchName,
+  };
+}
+
 function validateOrderedIds(body: unknown): string[] {
  if (!body || typeof body !== "object") {
    throw new Error("Request body must contain orderedIds array");
@@ -299,7 +332,7 @@ export function createMissionRouter(
  router.post(
    "/",
    catchTypedHandler(async (req, res) => {
-      const { title, description, autoAdvance, autopilotEnabled, baseBranch } = req.body;
+      const { title, description, autoAdvance, autopilotEnabled, baseBranch, branchStrategy } = req.body;

      const validatedTitle = validateTitle(title);
      const validatedDescription = validateDescription(description);
@@ -308,6 +341,7 @@ export function createMissionRouter(
        title: validatedTitle,
        description: validatedDescription,
        baseBranch: validateDescription(baseBranch),
+        branchStrategy: validateMissionBranchStrategy(branchStrategy),
      };

      const mission = missionStore.createMission(input);
@@ -880,7 +914,7 @@ export function createMissionRouter(
    "/:missionId",
    catchTypedHandler(async (req, res) => {
      const { missionId } = req.params;
-      const { title, description, status, autoAdvance, autopilotEnabled, baseBranch } = req.body;
+      const { title, description, status, autoAdvance, autopilotEnabled, baseBranch, branchStrategy } = req.body;

      if (!validateMissionId(missionId)) {
        throw badRequest("Invalid mission ID format");
@@ -906,6 +940,9 @@ export function createMissionRouter(
      if (baseBranch !== undefined) {
        updates.baseBranch = validateDescription(baseBranch);
      }
+      if (branchStrategy !== undefined) {
+        updates.branchStrategy = validateMissionBranchStrategy(branchStrategy);
+      }

      if (Object.keys(updates).length === 0) {
        throw badRequest("No valid fields to update");