diff --git a/.agents/session-log.md b/.agents/session-log.md
index e5d229b..a062859 100644
--- a/.agents/session-log.md
+++ b/.agents/session-log.md
@@ -1,5 +1,20 @@
 # Session Log - QuantLab
 
+## 2026-04-10 — Real-Path Desktop Validation and Smoke Semantics (Issue #275)
+- **Session Focus**: Restore an honest distinction between fallback desktop smoke and real-path desktop validation.
+- **Tasks Completed**:
+  - Updated `desktop/scripts/smoke.js` to parse an explicit `--mode` and pass the selected smoke mode into Electron.
+  - Kept fallback smoke on the local-shell path by disabling server boot only in fallback mode.
+  - Hardened `desktop/main.js` so real-path smoke only succeeds when `research_ui` becomes reachable instead of accepting local-runs fallback.
+  - Updated GitHub Actions to run the explicit `smoke:real-path` path under the dedicated `desktop-real-path` job name.
+- **Key Decisions**:
+  - `smoke:fallback` remains useful for shell/bootstrap coverage, but its semantics stay intentionally tolerant.
+  - `smoke:real-path` now means real `research_ui` reachability; local runs no longer count as success for that mode.
+  - CI naming now reflects the stronger guarantee instead of implying generic smoke coverage.
+- **Validation Notes**:
+  - Validate locally with both `npm run smoke:fallback` and `npm run smoke:real-path` from `desktop/`.
+  - Confirm workflow syntax and behavior with the desktop smoke commands before opening the PR.
+
 ## 2026-03-24 — Canonical Run Machine Contract (Issue #62)
 - **Session Focus**: Reduce the remaining contract asymmetry between plain `run` and `sweep` inside canonical `report.json`.
 - **Tasks Completed**:
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9bd1fdf..e4bb11e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -26,7 +26,7 @@ jobs:
         run: |
           python -m pytest -q
 
-  desktop-smoke:
+  desktop-real-path:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
@@ -53,7 +53,7 @@ jobs:
         run: |
           npm ci
 
-      - name: Run desktop smoke
+      - name: Run desktop real-path smoke
         working-directory: desktop
         run: |
-          xvfb-run -a npm run smoke
+          xvfb-run -a npm run smoke:real-path
diff --git a/desktop/main.js b/desktop/main.js
index d29660e..173e010 100644
--- a/desktop/main.js
+++ b/desktop/main.js
@@ -30,6 +30,7 @@ const RESEARCH_UI_HEALTH_PATH = "/api/paper-sessions-health";
 const RESEARCH_UI_STARTUP_TIMEOUT_MS = 25000;
 const ELECTRON_STATE_ROOT = path.join(DESKTOP_OUTPUTS_ROOT, "electron");
 const IS_SMOKE_RUN = process.env.QUANTLAB_DESKTOP_SMOKE === "1";
+const SMOKE_MODE = process.env.QUANTLAB_DESKTOP_SMOKE_MODE === "real-path" ? "real-path" : "fallback";
 const SMOKE_OUTPUT_PATH = process.env.QUANTLAB_DESKTOP_SMOKE_OUTPUT || "";
 const SKIP_RESEARCH_UI_BOOT = process.env.QUANTLAB_DESKTOP_DISABLE_SERVER_BOOT === "1";
 let smokeResultPersisted = false;
@@ -364,6 +365,19 @@ async function readProjectJson(targetPath) {
   }
 }
 
+async function readJsonFile(targetPath) {
+  const raw = await fsp.readFile(targetPath, "utf8");
+  try {
+    return JSON.parse(raw);
+  } catch (_error) {
+    const sanitized = raw
+      .replace(/\bNaN\b/g, "null")
+      .replace(/\b-Infinity\b/g, "null")
+      .replace(/\bInfinity\b/g, "null");
+    return JSON.parse(sanitized);
+  }
+}
+
 function parseYamlSectionValue(raw, sectionName, keyName) {
   const sectionPattern = new RegExp(`^${sectionName}:\\s*\\r?\\n([\\s\\S]*?)(?=^\\S|\\Z)`, "m");
   const sectionMatch = String(raw || "").match(sectionPattern);
@@ -905,16 +919,26 @@ async function runDesktopSmoke() {
       await new Promise((resolve) => setTimeout(resolve, 250));
     }
     try {
-      const localRuns = await readProjectJson("outputs/runs/runs_index.json");
+      const localRuns = IS_SMOKE_RUN
+        ? await readJsonFile(path.join(OUTPUTS_ROOT, "runs", "runs_index.json"))
+        : await readProjectJson("outputs/runs/runs_index.json");
       result.localRunsReady = Array.isArray(localRuns?.runs);
     } catch (_error) {
       result.localRunsReady = false;
     }
-    result.shellReady = result.bridgeReady && (result.serverReady || result.localRunsReady);
+    result.shellReady = result.bridgeReady && (
+      SMOKE_MODE === "real-path"
+        ? result.serverReady
+        : (result.serverReady || result.localRunsReady)
+    );
     if (!result.serverReady) {
-      result.error = workspaceState.error || (result.localRunsReady
-        ? "research_ui did not become reachable, but the shell loaded via the local runs index."
-        : "research_ui did not become reachable during smoke run.");
+      result.error = workspaceState.error || (
+        SMOKE_MODE === "real-path"
+          ? "research_ui did not become reachable during real-path smoke run."
+          : (result.localRunsReady
+              ? "research_ui did not become reachable, but the shell loaded via the local runs index."
+              : "research_ui did not become reachable during smoke run.")
+      );
     }
   } catch (error) {
     result.error = error.message;
diff --git a/desktop/scripts/smoke.js b/desktop/scripts/smoke.js
index cdf5db4..4491b4d 100644
--- a/desktop/scripts/smoke.js
+++ b/desktop/scripts/smoke.js
@@ -6,7 +6,19 @@ const { spawn } = require("child_process");
 /** @typedef {import("../shared/models/smoke").SmokeMode} SmokeMode */
 /** @typedef {import("../shared/models/smoke").SmokeResult} SmokeResult */
 
+function parseSmokeMode(argv) {
+  const rawMode = argv
+    .map((entry) => String(entry || "").trim())
+    .find((entry) => entry.startsWith("--mode="))
+    ?.slice("--mode=".length);
+  if (!rawMode || rawMode === "fallback" || rawMode === "real-path") {
+    return /** @type {SmokeMode} */ (rawMode || "fallback");
+  }
+  throw new Error(`Unsupported desktop smoke mode: ${rawMode}`);
+}
+
 async function main() {
+  const mode = parseSmokeMode(process.argv.slice(2));
   const desktopRoot = path.resolve(__dirname, "..");
   const projectRoot = path.resolve(desktopRoot, "..");
   const electronBinary = require("electron");
@@ -15,8 +27,8 @@ async function main() {
   const outputPath = path.join(tempRoot, "result.json");
   const desktopOutputsRoot = path.join(tempRoot, "outputs");
   const workspaceStatePath = path.join(desktopOutputsRoot, "desktop", "workspace_state.json");
-  const projectRunsDir = path.join(projectRoot, "outputs", "runs");
-  const projectRunsIndexPath = path.join(projectRunsDir, "runs_index.json");
+  const smokeRunsDir = path.join(desktopOutputsRoot, "runs");
+  const smokeRunsIndexPath = path.join(smokeRunsDir, "runs_index.json");
   let seededRunsIndex = false;
 
   await fs.mkdir(path.dirname(workspaceStatePath), { recursive: true });
@@ -51,11 +63,11 @@ async function main() {
   );
 
   try {
-    await fs.access(projectRunsIndexPath);
+    await fs.access(smokeRunsIndexPath);
   } catch (_error) {
-    await fs.mkdir(projectRunsDir, { recursive: true });
+    await fs.mkdir(smokeRunsDir, { recursive: true });
     await fs.writeFile(
-      projectRunsIndexPath,
+      smokeRunsIndexPath,
       `${JSON.stringify({
         updated_at: new Date().toISOString(),
         runs: [
@@ -86,9 +98,10 @@ async function main() {
       env: {
         ...process.env,
         QUANTLAB_DESKTOP_SMOKE: "1",
+        QUANTLAB_DESKTOP_SMOKE_MODE: mode,
         QUANTLAB_DESKTOP_SMOKE_OUTPUT: outputPath,
         QUANTLAB_DESKTOP_OUTPUTS_ROOT: desktopOutputsRoot,
-        QUANTLAB_DESKTOP_DISABLE_SERVER_BOOT: "1",
+        ...(mode === "fallback" ? { QUANTLAB_DESKTOP_DISABLE_SERVER_BOOT: "1" } : {}),
       },
     });
     let stdout = "";
@@ -129,10 +142,15 @@ async function main() {
       );
     }
 
-    if (exitCode !== 0 || !result.bridgeReady || !result.shellReady) {
+    const passed =
+      mode === "real-path"
+        ? exitCode === 0 && result.bridgeReady && result.serverReady && result.apiReady
+        : exitCode === 0 && result.bridgeReady && result.shellReady;
+
+    if (!passed) {
       if (stdout.trim()) console.error(stdout.trim());
       if (stderr.trim()) console.error(stderr.trim());
-      throw new Error(`Desktop smoke failed: ${JSON.stringify(result)}`);
+      throw new Error(`Desktop smoke (${mode}) failed: ${JSON.stringify(result)}`);
     }
 
     const persistedWorkspaceRaw = await fs.readFile(workspaceStatePath, "utf8");
@@ -144,13 +162,15 @@ async function main() {
     }
 
     console.log(
-      result.serverReady
-        ? `Desktop smoke passed via ${result.serverUrl}`
-        : "Desktop smoke passed via local runs fallback",
+      mode === "real-path"
+        ? `Desktop smoke real-path passed via ${result.serverUrl}`
+        : (result.serverReady
+            ? `Desktop smoke fallback passed via ${result.serverUrl}`
+            : "Desktop smoke fallback passed via local runs fallback"),
     );
   } finally {
     if (seededRunsIndex) {
-      await fs.rm(projectRunsIndexPath, { force: true }).catch(() => {});
+      await fs.rm(smokeRunsIndexPath, { force: true }).catch(() => {});
     }
   }
 }