docs: clarify OpenAI fast mode precedence (#120682)

docs/cli/config.md

@@ -114,6 +114,13 @@ openclaw config validate --json
 If validation is already failing, start with `openclaw configure` or `openclaw doctor --fix`. `openclaw chat` does not bypass the invalid-config guard.
 </Note>
 
+Provider and runtime `params` bags are intentionally typed as
+`Record<string, unknown>` because their owners define the supported keys and
+values. `openclaw config validate` can validate the container and overall
+config shape, but it cannot type-check provider-specific parameter names or
+values. Passing validation does not prove that a param is supported; consult
+the provider docs and verify behavior on the selected runtime and provider.
+
 ## Values
 
 Values parse as JSON5 when possible; otherwise they are treated as raw strings. Use `--strict-json` to require standard JSON with no string fallback (JSON5-only syntax such as comments, trailing commas, or unquoted keys is then rejected). `--json` is a legacy alias for `--strict-json` on `config set`.
@@ -301,13 +308,20 @@ Example patch:
     defaults: {
       model: { primary: "openai/gpt-5.6-sol" },
       models: {
-        "openai/gpt-5.6-sol": { params: { fastMode: true } },
+        "openai/gpt-5.6-sol": {
+          agentRuntime: { id: "openclaw" },
+          params: { fastMode: true },
+        },
       },
     },
   },
 }
 ```
 
+The runtime pin makes this an embedded OpenClaw recipe. A valid `fastMode`
+value is a portable typed runtime control and does not choose OpenClaw by
+itself.
+
 Use `--replace-path <path>` when one object or array must become exactly the provided value instead of being recursively patched:
 
 ```bash