fix(codex): split the stack comp_hash by tool protocol

In the merged (stack) catalog every third-party row shared one comp_hash,
"cc-switch", so Codex never compacted when switching between them (#8485).
Third-party GPT rows mirror the official entry and carry
`tool_mode: "code_mode_only"`, where shell calls are recorded as the
custom tool `exec`; DeepSeek, Kimi and other rows are direct and only have
`exec_command`. After switching from a GPT row to a direct row without
compaction, the direct model copied the `exec` calls from history and
every turn failed with `unsupported call: exec`.

Group rows by tool protocol instead: a row with a tool_mode gets
"cc-switch-<tool_mode>", direct rows keep "cc-switch" so existing
sessions see no change. Switching within a group still skips compaction;
switching across groups compacts with the previous model first, which
folds the other protocol's calls into the summary. tool_mode and
supports_search_tool keep the template values, so third-party GPT rows
keep code mode. The cost is that a cross-group switch away from a
provider that is no longer usable fails to compact, as before #8485;
switching within the group or starting a new session avoids it.

Fixes #8676

src-tauri/src/codex_config.rs

@@ -2541,6 +2541,23 @@ pub(crate) enum CodexStackRoute<'a> {
 /// 压缩语义也要保留。
 const CODEX_STACK_COMP_HASH: &str = "cc-switch";
 
+/// 让一行加入合并目录里共用历史的那组：`comp_hash` 按工具协议分组，同协议的行共用一个值。
+///
+/// 镜像官方条目的第三方 GPT 行带着 `tool_mode: "code_mode_only"`，shell 调用在历史里是
+/// custom 工具 `exec`；其余第三方行是 direct，只有 `exec_command`。两者若共用一个值，切换时
+/// 不压缩，direct 模型会照着历史调用不存在的 `exec`，每轮都报 `unsupported call: exec`
+/// （#8676）。所以协议不同就分开：跨组切换先用上一家压缩，把对方协议的调用收进摘要；
+/// 组内切换照旧不压缩（#8485）。代价是跨组切换时上一家若不可用，压缩会失败，#8485 在这条
+/// 路径上回来；组内换一家或新开会话都能绕开。direct 行沿用 [`CODEX_STACK_COMP_HASH`]，
+/// 老会话记下的值不变。
+fn join_stack_history(obj: &mut serde_json::Map<String, Value>) {
+    let comp_hash = match obj.get("tool_mode").and_then(Value::as_str) {
+        Some(mode) => format!("{CODEX_STACK_COMP_HASH}-{mode}"),
+        None => CODEX_STACK_COMP_HASH.to_string(),
+    };
+    obj.insert("comp_hash".to_string(), json!(comp_hash));
+}
+
 /// Stack 名单非空时的模型目录：路由那家的行在前，各 Stack 供应商的行按名单顺序在后，
 /// `priority` 统一重新编号。
 ///
@@ -2558,7 +2575,7 @@ pub(crate) fn plan_codex_stack_catalog(
             let mut rows = codex_stack_third_party_rows(&row)?;
             for entry in &mut rows {
                 if let Some(obj) = entry.as_object_mut() {
-                    obj.insert("comp_hash".to_string(), json!(CODEX_STACK_COMP_HASH));
+                    join_stack_history(obj);
                 }
             }
             rows
@@ -2586,7 +2603,7 @@ pub(crate) fn plan_codex_stack_catalog(
             let Some(obj) = entry.as_object_mut() else {
                 continue;
             };
-            obj.insert("comp_hash".to_string(), json!(CODEX_STACK_COMP_HASH));
+            join_stack_history(obj);
             let Some(model) = obj.get("slug").and_then(Value::as_str).map(str::to_string) else {
                 continue;
             };
@@ -2647,7 +2664,8 @@ pub(crate) fn plan_codex_stack_catalog(
 /// `config.toml` 里 `[features] multi_agent_v2 = true` 比目录优先，这时写了也不生效。
 const CODEX_CLASSIC_SUBAGENTS: &str = "v1";
 
-/// 一家第三方供应商在合并目录里的行（`comp_hash` 保持模板的值，由调用方统一改写）。
+/// 一家第三方供应商在合并目录里的行（`comp_hash` 保持模板的值，由调用方经
+/// [`join_stack_history`] 统一改写）。
 pub(crate) fn codex_stack_third_party_rows(
     row: &CodexCatalogRow<'_>,
 ) -> Result<Vec<Value>, AppError> {
@@ -5836,6 +5854,67 @@ wire_api = "responses"
         }
     }
 
+    /// #8676：共用 `comp_hash` 的行切换时不压缩，所以按工具协议分组。镜像官方条目的第三方
+    /// GPT 行（路由那家和 Stack 成员）保留 code mode，自成一组；direct 行仍是原来的值。
+    /// 除 `comp_hash` 外，GPT 行和直连目录里的同一行一致。
+    #[test]
+    fn stack_rows_share_history_only_within_one_tool_protocol() {
+        let gpt_settings = json!({ "modelCatalog": { "models": [{ "model": "gpt-6-sol" }] } });
+        let gpt_text = "model = \"gpt-6-sol\"\n";
+        let ds_settings = json!({ "modelCatalog": { "models": [{ "model": "deepseek-v4-pro" }] } });
+        let ds_text = "model = \"deepseek-v4-pro\"\n";
+        let profile = CodexCatalogToolProfile::NativeResponses;
+        let row = |settings, config_text| CodexCatalogRow {
+            settings,
+            config_text,
+            profile,
+        };
+        let (direct, stacked) = with_official_models(official_gpt_rows(), || {
+            let direct = codex_model_catalog_from_settings(&gpt_settings, gpt_text, profile)
+                .unwrap()
+                .unwrap();
+            let stacked = plan_codex_stack_catalog(
+                CodexStackRoute::ThirdParty(row(&gpt_settings, gpt_text)),
+                &[
+                    CodexStackCatalogMember {
+                        key: "relay",
+                        provider_name: "Relay",
+                        row: row(&gpt_settings, gpt_text),
+                    },
+                    CodexStackCatalogMember {
+                        key: "ds",
+                        provider_name: "DS",
+                        row: row(&ds_settings, ds_text),
+                    },
+                ],
+                false,
+            )
+            .unwrap();
+            (direct, stacked)
+        });
+
+        let models = stacked["models"].as_array().unwrap();
+        let slugs: Vec<&str> = models.iter().map(|m| m["slug"].as_str().unwrap()).collect();
+        assert_eq!(
+            slugs,
+            vec!["gpt-6-sol", "ccs-relay/gpt-6-sol", "ccs-ds/deepseek-v4-pro"]
+        );
+        let mirrored = &direct["models"][0];
+        assert_eq!(mirrored["tool_mode"], "code_mode_only");
+        for gpt in &models[..2] {
+            assert_eq!(
+                gpt["comp_hash"], "cc-switch-code_mode_only",
+                "{}",
+                gpt["slug"]
+            );
+            for key in ["tool_mode", "supports_search_tool", "model_messages"] {
+                assert_eq!(gpt[key], mirrored[key], "{} {key}", gpt["slug"]);
+            }
+        }
+        assert!(models[2].get("tool_mode").is_none());
+        assert_eq!(models[2]["comp_hash"], "cc-switch");
+    }
+
     #[test]
     fn stacked_rows_keep_their_own_tool_profile_and_never_use_responses_lite() {
         let route_settings = json!({ "modelCatalog": { "models": [{ "model": "route-model" }] } });