fix(mesh): make recommended agent model actionable

Preserve user token controls through the shared-compute spawn path and preselect the hardware-ranked Gemma recommendation for first-time sharing.\n\nCo-authored-by: Bartok9 <danielrpike9@gmail.com>\nCo-authored-by: Taksh <takshkothari09@gmail.com>

Signed-off-by: Michael Neale <michael.neale@gmail.com>

desktop/src-tauri/src/managed_agents/relay_mesh.rs

@@ -44,13 +44,42 @@ pub fn apply_relay_mesh_env(
     );
     // Keep the requested response inside smaller local-model context windows,
     // and spend that budget on an answer/tool call instead of hidden reasoning.
-    // Without both settings Qwen3 either fails the router's fit check at the
-    // agent default (32K) or can consume a tight cap before serializing a tool.
-    env.insert(
-        "BUZZ_AGENT_MAX_OUTPUT_TOKENS".to_string(),
-        "4096".to_string(),
-    );
-    env.insert("BUZZ_AGENT_THINKING_EFFORT".to_string(), "none".to_string());
+    // These are defaults, not policy: the effective agent/persona/global env
+    // may deliberately choose a smaller cap or enable thinking. This function
+    // runs after those layers during readiness, so never clobber their values.
+    insert_default_if_unset(env, "BUZZ_AGENT_MAX_OUTPUT_TOKENS", "4096");
+    insert_default_if_unset(env, "BUZZ_AGENT_THINKING_EFFORT", "none");
+}
+
+#[cfg(feature = "mesh-llm")]
+fn insert_default_if_unset(
+    env: &mut std::collections::BTreeMap<String, String>,
+    key: &str,
+    value: &str,
+) {
+    if env.get(key).is_none_or(|current| current.trim().is_empty()) {
+        env.insert(key.to_string(), value.to_string());
+    }
+}
+
+/// Build the final Mesh-specific process overrides from the already-resolved
+/// harness environment. Only user-owned generation controls are seeded: the
+/// derived provider/base URL/model values remain authoritative, and unrelated
+/// credentials (notably `OPENAI_API_KEY`) must not be copied back after the
+/// spawn path removes them.
+#[cfg(feature = "mesh-llm")]
+pub fn relay_mesh_process_env(
+    effective_env: &std::collections::BTreeMap<String, String>,
+    model: &str,
+) -> std::collections::BTreeMap<String, String> {
+    let mut env = std::collections::BTreeMap::new();
+    for key in ["BUZZ_AGENT_MAX_OUTPUT_TOKENS", "BUZZ_AGENT_THINKING_EFFORT"] {
+        if let Some(value) = effective_env.get(key) {
+            env.insert(key.to_string(), value.clone());
+        }
+    }
+    apply_relay_mesh_env(&mut env, Some(RELAY_MESH_PROVIDER_ID), Some(model));
+    env
 }
 
 #[cfg(all(test, feature = "mesh-llm"))]
@@ -82,4 +111,52 @@ mod tests {
             Some("1")
         );
     }
+
+    #[test]
+    fn native_provider_preserves_explicit_generation_controls() {
+        let mut env = BTreeMap::from([
+            (
+                "BUZZ_AGENT_MAX_OUTPUT_TOKENS".to_string(),
+                "2048".to_string(),
+            ),
+            ("BUZZ_AGENT_THINKING_EFFORT".to_string(), "low".to_string()),
+        ]);
+        apply_relay_mesh_env(
+            &mut env,
+            Some(RELAY_MESH_PROVIDER_ID),
+            Some(RELAY_MESH_AUTO_MODEL_ID),
+        );
+
+        assert_eq!(
+            env.get("BUZZ_AGENT_MAX_OUTPUT_TOKENS").map(String::as_str),
+            Some("2048")
+        );
+        assert_eq!(
+            env.get("BUZZ_AGENT_THINKING_EFFORT").map(String::as_str),
+            Some("low")
+        );
+    }
+
+    #[test]
+    fn process_env_seeds_controls_without_restoring_unrelated_credentials() {
+        let effective_env = BTreeMap::from([
+            (
+                "BUZZ_AGENT_MAX_OUTPUT_TOKENS".to_string(),
+                "1024".to_string(),
+            ),
+            ("OPENAI_API_KEY".to_string(), "must-not-leak".to_string()),
+        ]);
+
+        let env = relay_mesh_process_env(&effective_env, "Gemma-4");
+
+        assert_eq!(
+            env.get("BUZZ_AGENT_MAX_OUTPUT_TOKENS").map(String::as_str),
+            Some("1024")
+        );
+        assert_eq!(
+            env.get("OPENAI_COMPAT_MODEL").map(String::as_str),
+            Some("Gemma-4")
+        );
+        assert!(!env.contains_key("OPENAI_API_KEY"));
+    }
 }

desktop/src-tauri/src/managed_agents/runtime.rs

@@ -869,12 +869,7 @@ pub fn spawn_agent_child(
     // uses the same trim semantics as the preflight callers.
     #[cfg(feature = "mesh-llm")]
     if let Some(ref mesh_model_id) = mesh_model_id {
-        let mut mesh_env = std::collections::BTreeMap::new();
-        super::apply_relay_mesh_env(
-            &mut mesh_env,
-            Some(super::RELAY_MESH_PROVIDER_ID),
-            Some(mesh_model_id.as_str()),
-        );
+        let mesh_env = super::relay_mesh_process_env(&descriptor.env, mesh_model_id);
         command.env_remove("OPENAI_API_KEY");
         for (key, value) in mesh_env {
             command.env(key, value);

desktop/src/features/mesh-compute/ui/MeshComputeSettingsCard.tsx

@@ -107,7 +107,9 @@ export function MeshComputeSettingsCard() {
 
   // One-shot hardware-aware catalog fetch. Purely additive: when it fails
   // (stub build, survey error) the card falls back to the free-text field.
-  // Keep an empty draft empty so the UI can explicitly ask the member to choose.
+  // When there is no saved choice, make the curated recommendation the actual
+  // default so a new member can turn Share Compute on directly. An explicit
+  // saved draft always wins.
   React.useEffect(() => {
     let cancelled = false;
     (async () => {
@@ -115,6 +117,11 @@ export function MeshComputeSettingsCard() {
         const value = await meshModelCatalog();
         if (cancelled) return;
         setCatalog(value);
+        setModelInput((current) => {
+          if (current.trim() !== "" || !value.recommended) return current;
+          writeDraft(MODEL_DRAFT_STORAGE_KEY, value.recommended);
+          return value.recommended;
+        });
       } catch {
         // Non-fatal — picker just doesn't render.
       }

desktop/src/testing/e2eBridge.ts

@@ -2887,9 +2887,7 @@ const mockMeshState: {
   servingUsage: MockServingUsage;
 } = {
   admitted: true,
-  models: [
-    { id: "hf://demo/SmolLM2-135M-Instruct-GGUF:Q4_K_M", name: "SmolLM2 135M" },
-  ],
+  models: [{ id: "Gemma-4-E4B-it-Q4_K_M", name: "Gemma 4 E4B" }],
   denyReason: "not a relay member",
   nodeState: "off",
   nodeMode: null,
@@ -2898,9 +2896,7 @@ const mockMeshState: {
 
 function resetMockMesh() {
   mockMeshState.admitted = true;
-  mockMeshState.models = [
-    { id: "hf://demo/SmolLM2-135M-Instruct-GGUF:Q4_K_M", name: "SmolLM2 135M" },
-  ];
+  mockMeshState.models = [{ id: "Gemma-4-E4B-it-Q4_K_M", name: "Gemma 4 E4B" }];
   mockMeshState.denyReason = "not a relay member";
   mockMeshState.nodeState = "off";
   mockMeshState.nodeMode = null;
@@ -9736,6 +9732,25 @@ export function maybeInstallE2eTauriMocks() {
       }
       case "mesh_installed_models":
         return mockMeshState.models;
+      case "mesh_model_catalog":
+        return {
+          gpuName: "Mock Apple GPU",
+          vramDisplay: "32 GB",
+          vramGb: 32,
+          recommended: "Gemma-4-E4B-it-Q4_K_M",
+          entries: [
+            {
+              name: "Gemma-4-E4B-it-Q4_K_M",
+              size: "3.5GB",
+              sizeGb: 3.5,
+              description: "Buzz-curated local agent model",
+              fit: "comfortable",
+              installed: true,
+              recommended: true,
+              curated: true,
+            },
+          ],
+        };
       case "mesh_node_status":
         return meshNodeStatus(mockMeshState.nodeState, mockMeshState.nodeMode);
       case "mesh_serving_usage":

desktop/tests/e2e/mesh-compute.spec.ts

@@ -15,7 +15,7 @@ type E2eWindow = Window & {
   }) => void;
 };
 
-test("Share compute has a clear empty state and starts and stops sharing", async ({
+test("Share compute selects the curated default and starts and stops sharing", async ({
   page,
 }) => {
   await installMockBridge(page);
@@ -30,22 +30,32 @@ test("Share compute has a clear empty state and starts and stops sharing", async
   await expect(card).toContainText(
     "Choose a suggested model below, or enter a model reference or local file",
   );
-  await expect(toggle).toBeDisabled();
-
-  await model.fill("hf://demo/SmolLM2-135M-Instruct-GGUF:Q4_K_M");
+  await expect(model).toHaveValue("Gemma-4-E4B-it-Q4_K_M");
+  await expect(toggle).toBeEnabled();
   await expect(card).toContainText(
     "Buzz downloads remote models when sharing starts",
   );
-  await expect(toggle).toBeEnabled();
 
   await toggle.click();
   await expect(toggle).toBeChecked();
-  await expect(card).toContainText("Sharing SmolLM2 135M with relay members");
+  await expect(card).toContainText("Sharing Gemma 4 E4B with relay members");
   await expect
     .poll(() =>
       page.evaluate(() => (window as E2eWindow).__BUZZ_E2E_COMMANDS__ ?? []),
     )
     .toContain("mesh_start_node");
+  await expect
+    .poll(() =>
+      page.evaluate(
+        () => (window as E2eWindow).__BUZZ_E2E_COMMAND_PAYLOADS__ ?? [],
+      ),
+    )
+    .toContainEqual({
+      command: "mesh_start_node",
+      payload: {
+        request: { mode: "serve", modelId: "Gemma-4-E4B-it-Q4_K_M" },
+      },
+    });
 
   await toggle.click();
   await expect(toggle).not.toBeChecked();