fix(adaptive): keep string key_strategy inputs serializable

Address CodeRabbit review on #818.

- `ResponseCacheConfig.to_dict()` in Python no longer raises `AttributeError`
  when `key_strategy` is a plain wire string. Enum members serialize through
  `.value`; strings pass through unchanged so unsupported values reach native
  validation with the `response_cache.unsupported_key_strategy` diagnostic,
  matching the Go string alias and the Node.js runtime.
- Drop the stale "exact-match" wording from the two `response_cache` doc
  comments in `crates/adaptive/src/config.rs`.

User-facing docs stay deferred to #819.

Signed-off-by: Zhongxuan (Daniel) Wang <52872691+ZhongxuanWang@users.noreply.github.com>

Author: ZhongxuanWang

crates/adaptive/src/config.rs

@@ -34,7 +34,7 @@ pub struct AdaptiveConfig {
     /// Adaptive Cache Governor settings.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub acg: Option<AcgComponentConfig>,
-    /// Opt-in exact-match LLM response and tool-result cache. When present,
+    /// Opt-in LLM response and tool-result cache. When present,
     /// the adaptive plugin installs the response-cache execution intercept(s).
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub response_cache: Option<ResponseCacheConfig>,
@@ -191,7 +191,7 @@ impl Default for AcgComponentConfig {
     }
 }
 
-/// Configuration for the adaptive plugin's exact-match LLM response and
+/// Configuration for the adaptive plugin's LLM response and
 /// opt-in tool-result cache feature.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(default)]

python/nemo_relay/adaptive.py

@@ -419,7 +419,11 @@ def to_dict(self) -> JsonObject:
                 "priority": self.priority,
                 "bypass_rate": self.bypass_rate,
                 "cache_nondeterministic": self.cache_nondeterministic,
-                "key_strategy": self.key_strategy.value,
+                "key_strategy": (
+                    self.key_strategy.value
+                    if isinstance(self.key_strategy, ResponseCacheKeyStrategy)
+                    else self.key_strategy
+                ),
                 "header_allowlist": self.header_allowlist,
                 "backend": _normalize(self.backend),
                 "tools": _normalize(self.tools),