fix: harden Gmail hook model defaults (#472) (thanks @koala73)

docs/automation/gmail-pubsub.md

@@ -65,6 +65,25 @@ uses the last delivery route (falls back to WhatsApp).
 To force a cheaper model for Gmail runs, set `model` in the mapping
 (`provider/model` or alias). If you enforce `agents.defaults.models`, include it there.
 
+To set a default model and thinking level specifically for Gmail hooks, add
+`hooks.gmail.model` / `hooks.gmail.thinking` in your config:
+
+```json5
+{
+  hooks: {
+    gmail: {
+      model: "openrouter/meta-llama/llama-3.3-70b-instruct:free",
+      thinking: "off"
+    }
+  }
+}
+```
+
+Notes:
+- Per-hook `model`/`thinking` in the mapping still overrides these defaults.
+- Fallback order: `hooks.gmail.model` → `agents.defaults.model.fallbacks` → primary (auth/rate-limit/timeouts).
+- If `agents.defaults.models` is set, the Gmail model must be in the allowlist.
+
 To customize payload handling further, add `hooks.mappings` or a JS/TS transform module
 under `hooks.transformsDir` (see [`docs/webhook.md`](https://docs.clawd.bot/automation/webhook)).