diff --git a/docs/manage-sandboxes/runtime-controls.mdx b/docs/manage-sandboxes/runtime-controls.mdx
index a55ccf862ae..a50ccdfd837 100644
--- a/docs/manage-sandboxes/runtime-controls.mdx
+++ b/docs/manage-sandboxes/runtime-controls.mdx
@@ -33,6 +33,7 @@ The table below maps each commonly changed item to the layer that owns it and th
 | Channel enable/disable (turn a configured channel off without removing the token) | Rebuild required (`openclaw.json` is the source of truth at runtime, see #3453) | `$$nemoclaw <name> channels stop <channel>` then rebuild |
 | Dashboard forward port | Runtime. Port is re-resolved on next `connect` | `NEMOCLAW_DASHBOARD_PORT=<port> $$nemoclaw <name> connect` |
 | Dashboard bind address (loopback compared to all interfaces) | Runtime. Applies on next `connect` | `NEMOCLAW_DASHBOARD_BIND=0.0.0.0 $$nemoclaw <name> connect` (see #3259) |
+| Default OpenClaw workspace template seed (`AGENTS.md`, `SOUL.md`, `IDENTITY.md`, `USER.md`, `TOOLS.md`, `HEARTBEAT.md`) | Locked at first sandbox boot. Re-onboard required to change the bake-time choice. | Set `NEMOCLAW_MINIMAL_BOOTSTRAP=1` before `$$nemoclaw onboard` to skip default template seeding for new/pristine workspaces. **Does not delete files already present.** Partial mitigation for #2598 (cuts ~3k tokens of project-context overhead off OpenClaw's per-turn bootstrap injection). |
 | Web search backend (Brave, Tavily, and so on) | Runtime through `web.backend` config flag; rebuild only if `web.fetchEnabled` flips | `$$nemoclaw <name> config set --key web.backend --value tavily` |
 | Filesystem layout (Landlock zones, read-only mounts, container caps) | **Locked at creation**. No runtime change | Re-onboard with `$$nemoclaw onboard --recreate-sandbox` |
 | Sandbox name | **Locked at creation** | Re-onboard with a different `--name` |
diff --git a/scripts/nemoclaw-start.sh b/scripts/nemoclaw-start.sh
index b3387529318..57837b497cc 100755
--- a/scripts/nemoclaw-start.sh
+++ b/scripts/nemoclaw-start.sh
@@ -2746,6 +2746,14 @@ seed_default_workspace_templates() {
   local templates_dir="${2:-}"
   local config_file="${3:-/sandbox/.openclaw/openclaw.json}"
 
+  # #2598: opt-in flag that skips default workspace template seeding for
+  # new/pristine workspaces (does NOT delete files already present). Cuts
+  # ~3k tokens off OpenClaw's per-turn bootstrap context injection.
+  if [ "${NEMOCLAW_MINIMAL_BOOTSTRAP:-}" = "1" ]; then
+    echo "[setup] NEMOCLAW_MINIMAL_BOOTSTRAP=1; skipping default workspace template seed" >&2
+    return 0
+  fi
+
   if [ ! -f "$config_file" ]; then
     return 0
   fi
diff --git a/src/lib/onboard/host-proxy-env.ts b/src/lib/onboard/host-proxy-env.ts
index 8b0f242a751..c0185961011 100644
--- a/src/lib/onboard/host-proxy-env.ts
+++ b/src/lib/onboard/host-proxy-env.ts
@@ -29,6 +29,21 @@ export function appendHostProxyEnvArgs(
     }
   }
 
+  // #2598: NEMOCLAW_MINIMAL_BOOTSTRAP is a host-side opt-in flag (set to
+  // "1") that the sandbox's nemoclaw-start.sh:seed_default_workspace_templates
+  // reads to skip default workspace template seeding for new/pristine
+  // workspaces (does NOT delete files already present), knocking ~3k tokens
+  // off OpenClaw's per-turn bootstrap context injection. Partial #2598
+  // mitigation: addresses the project-context contribution from NemoClaw's
+  // seeded templates; the remaining OpenClaw framework/non-project context
+  // is tracked upstream. Bundled here with the proxy propagation because
+  // both are env vars forwarded from the host into `openshell sandbox
+  // create -- env ... nemoclaw-start`, and the top-level onboard.ts
+  // entrypoint is line-budget-constrained per codebase-growth-guardrails.
+  if (env.NEMOCLAW_MINIMAL_BOOTSTRAP === "1") {
+    envArgs.push(formatEnvAssignment("NEMOCLAW_MINIMAL_BOOTSTRAP", "1"));
+  }
+
   const hasProxy =
     proxyEnv.HTTP_PROXY || proxyEnv.HTTPS_PROXY || proxyEnv.http_proxy || proxyEnv.https_proxy;
   if (!hasProxy) return;
diff --git a/test/nemoclaw-start.test.ts b/test/nemoclaw-start.test.ts
index d00f2324069..78accada81d 100644
--- a/test/nemoclaw-start.test.ts
+++ b/test/nemoclaw-start.test.ts
@@ -2652,7 +2652,7 @@ describe("seed_default_workspace_templates (#3240)", () => {
     );
     return spawnSync("bash", [scriptPath], {
       encoding: "utf-8",
-      env: { ...process.env, ...(options.env ?? {}) },
+      env: { ...process.env, NEMOCLAW_MINIMAL_BOOTSTRAP: "", ...(options.env ?? {}) },
       timeout: 5000,
     });
   }
@@ -2934,6 +2934,52 @@ describe("seed_default_workspace_templates (#3240)", () => {
       fs.rmSync(tmpDir, { recursive: true, force: true });
     }
   });
+
+  it("skips seeding when NEMOCLAW_MINIMAL_BOOTSTRAP=1 (#2598)", () => {
+    const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "nemoclaw-seed-minimal-"));
+    const workspaceDir = path.join(tmpDir, "workspace");
+    const templatesDir = path.join(tmpDir, "templates");
+    fs.mkdirSync(workspaceDir, { recursive: true });
+    writeTemplates(templatesDir);
+    try {
+      const result = runSeed(workspaceDir, templatesDir, path.join(tmpDir, "seed.sh"), {
+        env: { NEMOCLAW_MINIMAL_BOOTSTRAP: "1" },
+      });
+      expect(result.status).toBe(0);
+      expect(result.stderr).toContain("NEMOCLAW_MINIMAL_BOOTSTRAP=1");
+      expect(result.stderr).toContain("skipping default workspace template seed");
+      for (const name of [
+        "AGENTS.md",
+        "SOUL.md",
+        "IDENTITY.md",
+        "USER.md",
+        "TOOLS.md",
+        "HEARTBEAT.md",
+      ]) {
+        expect(fs.existsSync(path.join(workspaceDir, name))).toBe(false);
+      }
+    } finally {
+      fs.rmSync(tmpDir, { recursive: true, force: true });
+    }
+  });
+
+  it("still seeds when NEMOCLAW_MINIMAL_BOOTSTRAP is not '1' (#2598)", () => {
+    const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "nemoclaw-seed-noopt-"));
+    const workspaceDir = path.join(tmpDir, "workspace");
+    const templatesDir = path.join(tmpDir, "templates");
+    fs.mkdirSync(workspaceDir, { recursive: true });
+    writeTemplates(templatesDir);
+    try {
+      const result = runSeed(workspaceDir, templatesDir, path.join(tmpDir, "seed.sh"), {
+        env: { NEMOCLAW_MINIMAL_BOOTSTRAP: "0" },
+      });
+      expect(result.status).toBe(0);
+      expect(result.stderr).not.toContain("skipping default workspace template seed");
+      expect(fs.existsSync(path.join(workspaceDir, "SOUL.md"))).toBe(true);
+    } finally {
+      fs.rmSync(tmpDir, { recursive: true, force: true });
+    }
+  });
 });
 
 describe("Slack secrets-on-disk tripwire (#2085)", () => {
diff --git a/test/onboard.test.ts b/test/onboard.test.ts
index 17a6ca861f5..761a9ad198e 100644
--- a/test/onboard.test.ts
+++ b/test/onboard.test.ts
@@ -173,6 +173,21 @@ describe("onboard helpers", () => {
     }
   });
 
+  it("propagates NEMOCLAW_MINIMAL_BOOTSTRAP=1 from host into sandbox env (#2598)", () => {
+    const envArgs: string[] = [];
+    appendHostProxyEnvArgs(envArgs, { NEMOCLAW_MINIMAL_BOOTSTRAP: "1" });
+    expect(envArgs).toContain("NEMOCLAW_MINIMAL_BOOTSTRAP=1");
+  });
+
+  it("omits NEMOCLAW_MINIMAL_BOOTSTRAP when unset or not the literal '1' (#2598)", () => {
+    for (const value of [undefined, "", "0", "true", "yes"]) {
+      const envArgs: string[] = [];
+      const env: NodeJS.ProcessEnv = value === undefined ? {} : { NEMOCLAW_MINIMAL_BOOTSTRAP: value };
+      appendHostProxyEnvArgs(envArgs, env);
+      expect(envArgs.some((e) => e.startsWith("NEMOCLAW_MINIMAL_BOOTSTRAP="))).toBe(false);
+    }
+  });
+
   it("prints doctor logs automatically when gateway fails to start (#1605)", testTimeoutOptions(20_000), () => {
     const repoRoot = path.join(import.meta.dirname, "..");
     const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "nemoclaw-gateway-diag-"));