diff --git a/CHANGELOG.md b/CHANGELOG.md
index 827b45e..25053c9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+### Changed
+
+- **Default `sonnet` alias → `claude-sonnet-5`.** The `sonnet` alias (the model used for every `/v1/chat/completions` request that omits `model`, and OpenClaw's OCP primary via `ocp-connect`) now resolves to `claude-sonnet-5` instead of `claude-sonnet-4-6`. `claude-sonnet-4-6` remains available by full ID for pinning. This is a behavior change for clients relying on the default — pin `claude-sonnet-4-6` explicitly to retain the previous model. Split out from the additive `claude-sonnet-5` model entry (#152) per Iron Rule 11.
+
 ## v3.22.1 — 2026-07-17
 
 Minor release: TUI-mode latency and streaming features — **all opt-in and off by default**, so the default request path (`-p` / `--output-format stream-json`) is byte-for-byte unchanged — plus hardening from an independent (Codex) re-review of the streaming work, Windows `claude.exe` startup resolution, and the Claude Sonnet 5 model entry. No new `cli.js` wire behavior and no new endpoint; the new surface is entirely OCP-owned TUI-mode configuration (env vars), startup binary discovery, model metadata, and `/health` observation. Every code PR carried a fresh-context reviewer (Iron Rule 10). (Version note: v3.22.0 was prepared but never tagged; its contents ship here as v3.22.1 together with the additions below.)
diff --git a/README.md b/README.md
index 7752cc0..c4c1e54 100644
--- a/README.md
+++ b/README.md
@@ -716,8 +716,8 @@ Any tool use happens server-side, under the `--allowedTools` set configured on t
 | `claude-opus-4-8` | Most capable (default for `opus` alias) |
 | `claude-opus-4-7` | Previous Opus, retained for pinning |
 | `claude-opus-4-6` | Older Opus, retained for pinning |
-| `claude-sonnet-5` | Latest Sonnet (available by full ID; `sonnet` alias repoint tracked separately) |
-| `claude-sonnet-4-6` | Good balance of speed/quality (default for `sonnet` alias) |
+| `claude-sonnet-5` | Latest Sonnet (default for `sonnet` alias) |
+| `claude-sonnet-4-6` | Previous Sonnet, retained for pinning |
 | `claude-haiku-4-5-20251001` | Fastest, lightweight (default for `haiku` alias) |
 
 The canonical list lives in [`models.json`](./models.json) — the single source of truth as of v3.11.0. Both `server.mjs` (the `/v1/models` endpoint) and `setup.mjs` (the OpenClaw registration) derive from it. Adding a new model is now a one-file edit:
diff --git a/models.json b/models.json
index 0f417f1..c311585 100644
--- a/models.json
+++ b/models.json
@@ -53,7 +53,7 @@
   ],
   "aliases": {
     "opus": "claude-opus-4-8",
-    "sonnet": "claude-sonnet-4-6",
+    "sonnet": "claude-sonnet-5",
     "haiku": "claude-haiku-4-5-20251001"
   },
   "legacyAliases": {
diff --git a/ocp-connect b/ocp-connect
index 1cc31d7..0722806 100755
--- a/ocp-connect
+++ b/ocp-connect
@@ -202,8 +202,13 @@ for mid in model_ids:
 
 # Handle primary/backup
 if priority == "1":
-    # OCP as primary — pick the best model (prefer sonnet for daily use)
-    primary_model = provider_name + "/claude-sonnet-4-6" if "claude-sonnet-4-6" in model_ids else provider_name + "/" + model_ids[0]
+    # OCP as primary — pick the best model (prefer the latest Sonnet for daily use,
+    # tracking the `sonnet` alias default in models.json; fall back across versions).
+    _sonnet_pref = ["claude-sonnet-5", "claude-sonnet-4-6"]
+    primary_model = next(
+        (provider_name + "/" + m for m in _sonnet_pref if m in model_ids),
+        provider_name + "/" + model_ids[0],
+    )
     config["agents"]["defaults"].setdefault("model", {})
     config["agents"]["defaults"]["model"]["primary"] = primary_model
     # Keep existing fallbacks
diff --git a/test-features.mjs b/test-features.mjs
index 0571b74..e9d5ca6 100644
--- a/test-features.mjs
+++ b/test-features.mjs
@@ -3322,8 +3322,8 @@ test("models.json aliases.haiku === 'claude-haiku-4-5-20251001' (usage-probe SPO
   assert.equal(_spotModels.aliases.haiku, "claude-haiku-4-5-20251001");
 });
 
-test("models.json aliases.sonnet === 'claude-sonnet-4-6' (default-request-model SPOT)", () => {
-  assert.equal(_spotModels.aliases.sonnet, "claude-sonnet-4-6");
+test("models.json aliases.sonnet === 'claude-sonnet-5' (default-request-model SPOT)", () => {
+  assert.equal(_spotModels.aliases.sonnet, "claude-sonnet-5");
 });
 
 // ── Referential integrity (PR #152 review) ──────────────────────────────────