fix: make Codex V2 agent payloads provider-agnostic

docs/superpowers/specs/2026-08-05-codex-cross-provider-v2-subagent-payload-design.md

@@ -17,14 +17,13 @@ because the official backend rejects any deviation with HTTP 400.
 
 The compatibility layer has two independent stages.
 
-Stage A runs only for an OpenAI-official parent request that belongs to a
-MultiRouter with at least one enabled third-party or ownership-ambiguous route.
-It removes only `parameters.properties.message.encrypted` from the non-reserved
+Stage A runs for any Codex parent request that belongs to a MultiRouter with at
+least one enabled third-party or ownership-ambiguous route. It removes only
+`parameters.properties.message.encrypted` from the non-reserved
 `agents.spawn_agent`, `agents.send_message`, and `agents.followup_task` schemas.
 It handles both top-level `tools` and Responses Lite `additional_tools`, including
 nested namespace containers. It never changes `collaboration.*`, unrelated
-functions, unrelated `encrypted` fields, third-party parent requests, or pure
-official routers.
+functions, unrelated `encrypted` fields, or pure official routers.
 
 Stage B runs only after the effective child route is known to be third-party. It
 projects every plaintext `agent_message` into a standard Responses
@@ -53,11 +52,10 @@ retain OpenAI encryption.
 ## Acceptance
 
 - Reserved `collaboration.*` schemas are byte/schema preserving.
-- Mixed-router official parents produce plaintext arguments only for `agents.*`.
+- Mixed-router parents produce plaintext arguments only for `agents.*`.
 - Top-level tools and Lite `additional_tools` behave identically.
 - Third-party child inputs contain ordinary user messages with readable payloads.
 - Opaque child ciphertext returns an explicit compatibility error.
-- OpenAI-to-OpenAI remains encrypted.
+- Pure OpenAI-to-OpenAI routers remain encrypted.
 - OpenAI-to-Qwen and OpenAI-to-DeepSeek children return a unique nonce plus real
   tool output in live tests after a full CCSwitchMulti and Codex restart.
-

src-tauri/src/proxy/forwarder.rs

@@ -2551,7 +2551,6 @@ impl RequestForwarder {
         if should_make_codex_v2_agents_plaintext(
             app_type,
             codex_router_provider,
-            normalize_codex_oauth_responses,
         ) {
             let changed = super::providers::openai_compat::make_codex_v2_agents_messages_plaintext(
                 &mut request_body,
@@ -7150,10 +7149,8 @@ fn codex_provider_has_routing_config(provider: &Provider) -> bool {
 fn should_make_codex_v2_agents_plaintext(
     app_type: &AppType,
     router_provider: &Provider,
-    official_oauth_request: bool,
 ) -> bool {
     matches!(app_type, AppType::Codex)
-        && official_oauth_request
         && super::providers::codex_multirouter_needs_plaintext_v2_collaboration(router_provider)
 }
 
@@ -8385,7 +8382,7 @@ mod tests {
     }
 
     #[test]
-    fn agents_plaintext_rewrite_requires_codex_mixed_router_and_official_parent() {
+    fn agents_plaintext_rewrite_applies_to_any_codex_mixed_router() {
         let mut mixed = test_provider_with_type(None);
         mixed.settings_config = json!({
             "codexRouting": {
@@ -8398,18 +8395,11 @@ mod tests {
         });
         assert!(should_make_codex_v2_agents_plaintext(
             &AppType::Codex,
-            &mixed,
-            true
-        ));
-        assert!(!should_make_codex_v2_agents_plaintext(
-            &AppType::Codex,
-            &mixed,
-            false
+            &mixed
         ));
         assert!(!should_make_codex_v2_agents_plaintext(
             &AppType::Claude,
-            &mixed,
-            true
+            &mixed
         ));
 
         let mut official_only = test_provider_with_type(None);
@@ -8424,8 +8414,22 @@ mod tests {
         });
         assert!(!should_make_codex_v2_agents_plaintext(
             &AppType::Codex,
-            &official_only,
-            true
+            &official_only
+        ));
+
+        let mut third_party_only = test_provider_with_type(None);
+        third_party_only.settings_config = json!({
+            "codexRouting": {
+                "enabled": true,
+                "routes": [{
+                    "enabled": true,
+                    "upstream": {"auth": {"source": "provider_config"}}
+                }]
+            }
+        });
+        assert!(should_make_codex_v2_agents_plaintext(
+            &AppType::Codex,
+            &third_party_only
         ));
     }