diff --git a/.github/workflows/smoke.yml b/.github/workflows/smoke.yml
index 13650c28..ec29f228 100644
--- a/.github/workflows/smoke.yml
+++ b/.github/workflows/smoke.yml
@@ -10,7 +10,7 @@ jobs:
   smoke:
     name: Testnet Smoke Tests
     runs-on: ubuntu-latest
-    timeout-minutes: 5
+    timeout-minutes: 10
     continue-on-error: true
 
     steps:
@@ -41,3 +41,5 @@ jobs:
 
       - name: Run smoke tests
         run: npm run test:smoke
+        env:
+          CLI_SMOKE_TIMEOUT_MS: 240000
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index e52bf0a0..5995aa80 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -33,19 +33,11 @@ Have ideas for new features or use cases? We're eager to hear them! But first:
 
 ## Branch model
 
-This repo uses a branch-per-major release model. There is no `main`.
-
-- **`v0.39`** — current stable major (semver-zero, so 0.39 IS the major; 0.40 would be a major bump that gets its own branch). PRs for bug fixes / non-breaking features target this branch.
-- **`v<next>-dev`** — when next-major work is in progress, this branch is open for breaking changes. PRs introducing them target this branch.
-- **Older majors** stay for back-ports. Default branch on github.com is whichever major is current stable.
-
-When you fork or clone, the default branch is `v0.39` today. If you have a `main` branch from a previous checkout, delete it locally:
-
-```sh
-git checkout v0.39
-git branch -D main
-git remote prune origin
-```
+See [docs/BRANCHING.md](docs/BRANCHING.md) for the current release-train model.
+In short: independently releasable work may target the stable branch directly;
+multi-feature or cross-repo train work uses the active `*-dev` integration
+branch and is promoted to the matching stable branch when ready. `main` is only
+the default/static GitHub branch.
 
 The previous `staging` branch (beta channel) has been retired. Pre-releases now go through the same release script with an explicit version (`scripts/release.sh 0.39.2-beta.0`).
 
@@ -138,4 +130,4 @@ Connect with the GenLayer community to discuss, collaborate, and share insights:
 - **[Discord Channel](https://discord.gg/8Jm4v89VAu)**: Our primary hub for discussions, support, and announcements.
 - **[Telegram Group](https://t.me/genlayer)**: For more informal chats and quick updates.
 
-Your continuous feedback drives better product development. Please engage with us regularly to test, discuss, and improve the GenLayer CLI.
\ No newline at end of file
+Your continuous feedback drives better product development. Please engage with us regularly to test, discuss, and improve the GenLayer CLI.
diff --git a/docs/BRANCHING.md b/docs/BRANCHING.md
new file mode 100644
index 00000000..5b8d3d60
--- /dev/null
+++ b/docs/BRANCHING.md
@@ -0,0 +1,58 @@
+# Branching and Release Trains
+
+This repo follows the GenLayer release-train model.
+
+## Current Train
+
+- Current stable branch: `v0.39`
+- Active integration branch: `v0.40-dev`
+- Next stable target: `v0.40`
+- `main`: default/static branch alias for the active integration branch
+
+## Stable Branches
+
+Stable branches are long-lived release lines. For semver-zero packages, each
+minor line is treated as the release line, for example `v0.39` or `v0.40`.
+
+PRs may target a stable branch directly when the merged result should be
+releasable immediately. This is appropriate for bug fixes, small non-breaking
+features, isolated release fixes, or a breaking change that is intentionally
+shipping as the next version by itself.
+
+Stable branches must remain releasable. PRs into stable branches are expected to
+pass the required cross-repo `E2E Tests` gate before merge.
+
+## Integration Branches
+
+Integration branches are optional. Use one when multiple changes need to
+accumulate before release, especially for cross-repo work, dependent features,
+breaking changes that must ship together, or a train that needs advisory E2E
+while still expected to be red.
+
+Integration branches are named after the target stable branch plus `-dev`, for
+example `v0.40-dev`. Feature PRs for that train target the integration branch.
+
+PRs into integration branches may run `E2E Tests` as advisory checks. They are
+not the release gate.
+
+## Promotion and Release
+
+When an integration train is ready, open a promotion PR from the integration
+branch to the matching stable branch, for example `v0.40-dev` to `v0.40`.
+
+That promotion PR is the release-readiness gate and must pass required
+cross-repo `E2E Tests`. The actual package release is cut from the stable branch
+using a version tag after the stable branch is ready.
+
+## `main`
+
+`main` exists for GitHub UX and tools that require a stable default branch. It is
+not a release branch and it is not the integration target.
+
+This repo keeps `main` forwarded to the active integration branch using
+automation. PRs opened against `main` are automatically retargeted to the branch
+listed in `support/ci/ACTIVE_DEV_BRANCH`.
+
+When changing the active integration branch, update
+`support/ci/ACTIVE_DEV_BRANCH`, the repo docs, and the corresponding
+`genlayer-e2e` release-train matrix in the same change set.
diff --git a/tests/smoke.test.ts b/tests/smoke.test.ts
index 56808871..7c34ed33 100644
--- a/tests/smoke.test.ts
+++ b/tests/smoke.test.ts
@@ -1,16 +1,19 @@
 import {describe, it, expect, beforeAll} from "vitest";
-import {execSync} from "child_process";
+import {execFile} from "child_process";
+import {promisify} from "util";
 import path from "path";
 import {createClient, parseStakingAmount, formatStakingAmount} from "genlayer-js";
 import {testnetAsimov, testnetBradbury} from "genlayer-js/chains";
 import type {Address, GenLayerChain} from "genlayer-js/types";
 
 const CLI = path.resolve(__dirname, "../dist/index.js");
+const execFileAsync = promisify(execFile);
 
 // Testnet validator-list fetches ALL validators + per-validator detail in
-// batches; on bradbury/asimov that routinely passes 30s. 90s gives headroom
-// without hiding real hangs.
+// batches; on bradbury/asimov that routinely passes 30s. Keep RPC calls capped
+// at 90s, but give the full CLI smoke path extra room for live testnet slowness.
 const TIMEOUT = 90_000;
+const CLI_TIMEOUT = Number(process.env.CLI_SMOKE_TIMEOUT_MS ?? 180_000);
 
 const testnets: {name: string; chain: GenLayerChain}[] = [
   {name: "Asimov", chain: testnetAsimov},
@@ -127,14 +130,16 @@ describe(`Testnet ${name} - CLI Staking Smoke Tests`, () => {
     }
   }, TIMEOUT);
 
-  it("CLI: genlayer staking validators lists validators", () => {
-    const output = execSync(
-      `node ${CLI} staking validators --network ${name === "Asimov" ? "testnet-asimov" : "testnet-bradbury"}`,
-      {encoding: "utf-8", timeout: TIMEOUT},
+  it("CLI: genlayer staking validators lists validators", async () => {
+    const {stdout, stderr} = await execFileAsync(
+      "node",
+      [CLI, "staking", "validators", "--network", name === "Asimov" ? "testnet-asimov" : "testnet-bradbury"],
+      {encoding: "utf-8", timeout: CLI_TIMEOUT},
     );
+    const output = `${stdout}${stderr}`;
     expect(output).toContain("active");
     expect(output).toMatch(/Total: \d+ validators/);
-  }, TIMEOUT);
+  }, CLI_TIMEOUT + 10_000);
 
   it("parseStakingAmount and formatStakingAmount round-trip", () => {
     const parsed = parseStakingAmount("1.5gen");