diff --git a/dist/cli/index.js b/dist/cli/index.js
index 1b78e6d..b1fa3f6 100644
--- a/dist/cli/index.js
+++ b/dist/cli/index.js
@@ -15347,7 +15347,9 @@ function loadRegistry(p) {
     raw = JSON.parse(fs3.readFileSync(filePath, "utf8"));
   } catch (err) {
     const msg = err instanceof Error ? err.message : String(err);
-    throw new Error(`Failed to parse registry JSON at ${filePath}: ${msg}`);
+    throw new Error(`Failed to parse registry JSON at ${filePath}: ${msg}`, {
+      cause: err
+    });
   }
   const result = WorkspaceRegistrySchema.safeParse(raw);
   if (!result.success) {
@@ -29378,7 +29380,7 @@ function loadLastRun() {
     raw = JSON.parse(fs17.readFileSync(filePath, "utf8"));
   } catch (err) {
     const msg = err instanceof Error ? err.message : String(err);
-    throw new Error(`Failed to parse last-run.json: ${msg}`);
+    throw new Error(`Failed to parse last-run.json: ${msg}`, { cause: err });
   }
   return validatePersistedRun(raw);
 }
@@ -30048,7 +30050,7 @@ function readDepNames(dir) {
 function collectEnvNames(dir, env) {
   const names = /* @__PURE__ */ new Set();
   for (const key of Object.keys(env)) addEnvName(names, key);
-  let entries = [];
+  let entries;
   try {
     entries = fs19.readdirSync(dir, { withFileTypes: true });
   } catch {
@@ -30149,7 +30151,9 @@ function scanWorkspaces(root) {
     entries = fs20.readdirSync(absRoot, { withFileTypes: true });
   } catch (err) {
     const msg = err instanceof Error ? err.message : String(err);
-    throw new Error(`Cannot read workspaces root "${absRoot}": ${msg}`);
+    throw new Error(`Cannot read workspaces root "${absRoot}": ${msg}`, {
+      cause: err
+    });
   }
   const workspaces = {};
   for (const entry of entries) {
diff --git a/dist/mcp/server.js b/dist/mcp/server.js
index f6fcba8..a340e84 100644
--- a/dist/mcp/server.js
+++ b/dist/mcp/server.js
@@ -47005,7 +47005,9 @@ function loadRegistry(p) {
     raw = JSON.parse(fs2.readFileSync(filePath, "utf8"));
   } catch (err) {
     const msg = err instanceof Error ? err.message : String(err);
-    throw new Error(`Failed to parse registry JSON at ${filePath}: ${msg}`);
+    throw new Error(`Failed to parse registry JSON at ${filePath}: ${msg}`, {
+      cause: err
+    });
   }
   const result = WorkspaceRegistrySchema.safeParse(raw);
   if (!result.success) {
@@ -53020,7 +53022,7 @@ function readDepNames(dir) {
 function collectEnvNames(dir, env) {
   const names = /* @__PURE__ */ new Set();
   for (const key of Object.keys(env)) addEnvName(names, key);
-  let entries = [];
+  let entries;
   try {
     entries = fs17.readdirSync(dir, { withFileTypes: true });
   } catch {
diff --git a/package.json b/package.json
index f2b6414..8fb577c 100644
--- a/package.json
+++ b/package.json
@@ -71,7 +71,7 @@
     "zod": "^4"
   },
   "devDependencies": {
-    "@eslint/js": "^9",
+    "@eslint/js": "^10",
     "@types/js-yaml": "^4",
     "@types/node": "^25",
     "esbuild": "0.28.1",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 189d71f..3b0ff2a 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -31,8 +31,8 @@ importers:
         version: 4.4.3
     devDependencies:
       '@eslint/js':
-        specifier: ^9
-        version: 9.39.4
+        specifier: ^10
+        version: 10.0.1(eslint@10.5.0)
       '@types/js-yaml':
         specifier: ^4
         version: 4.0.9
@@ -376,9 +376,14 @@ packages:
     resolution: {integrity: sha512-MwcE1P+AZ4C6DWlpin/OmOA54mmIZ/+xZuJiQd4SyB29oAJjN30UW9wkKNptW2ctp4cEsvhlLY/CsQ1uoHDloQ==}
     engines: {node: ^20.19.0 || ^22.13.0 || >=24}
 
-  '@eslint/js@9.39.4':
-    resolution: {integrity: sha512-nE7DEIchvtiFTwBw4Lfbu59PG+kCofhjsKaCWzxTpt4lfRjRMqG6uMBzKXuEcyXhOHoUp9riAm7/aWYGhXZ9cw==}
-    engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
+  '@eslint/js@10.0.1':
+    resolution: {integrity: sha512-zeR9k5pd4gxjZ0abRoIaxdc7I3nDktoXZk2qOv9gCNWx3mVwEn32VRhyLaRsDiJjTs0xq/T8mfPtyuXu7GWBcA==}
+    engines: {node: ^20.19.0 || ^22.13.0 || >=24}
+    peerDependencies:
+      eslint: ^10.0.0
+    peerDependenciesMeta:
+      eslint:
+        optional: true
 
   '@eslint/object-schema@3.0.5':
     resolution: {integrity: sha512-vqTaUEgxzm+YDSdElad6PiRoX4t8VGDjCtt05zn4nU810UIx/uNEV7/lZJ6KwFThKZOzOxzXy48da+No7HZaMw==}
@@ -1610,7 +1615,9 @@ snapshots:
     dependencies:
       '@types/json-schema': 7.0.15
 
-  '@eslint/js@9.39.4': {}
+  '@eslint/js@10.0.1(eslint@10.5.0)':
+    optionalDependencies:
+      eslint: 10.5.0
 
   '@eslint/object-schema@3.0.5': {}
 
diff --git a/src/discovery/detect.ts b/src/discovery/detect.ts
index aa7eb27..be09d09 100644
--- a/src/discovery/detect.ts
+++ b/src/discovery/detect.ts
@@ -89,7 +89,7 @@ function collectEnvNames(dir: string, env: Record<string, string | undefined>):
   const names = new Set<string>();
   for (const key of Object.keys(env)) addEnvName(names, key);
 
-  let entries: fs.Dirent[] = [];
+  let entries: fs.Dirent[];
   try {
     entries = fs.readdirSync(dir, { withFileTypes: true });
   } catch {
diff --git a/src/registry/init.ts b/src/registry/init.ts
index ce64450..f0ce1f4 100644
--- a/src/registry/init.ts
+++ b/src/registry/init.ts
@@ -94,7 +94,9 @@ export function scanWorkspaces(root: string): WorkspaceRegistry {
     entries = fs.readdirSync(absRoot, { withFileTypes: true });
   } catch (err) {
     const msg = err instanceof Error ? err.message : String(err);
-    throw new Error(`Cannot read workspaces root "${absRoot}": ${msg}`);
+    throw new Error(`Cannot read workspaces root "${absRoot}": ${msg}`, {
+      cause: err,
+    });
   }
 
   const workspaces: Record<string, WorkspaceEntry> = {};
diff --git a/src/registry/loader.ts b/src/registry/loader.ts
index 170bc74..47c8295 100644
--- a/src/registry/loader.ts
+++ b/src/registry/loader.ts
@@ -19,7 +19,9 @@ export function loadRegistry(p?: string): WorkspaceRegistry {
     raw = JSON.parse(fs.readFileSync(filePath, "utf8")) as unknown;
   } catch (err) {
     const msg = err instanceof Error ? err.message : String(err);
-    throw new Error(`Failed to parse registry JSON at ${filePath}: ${msg}`);
+    throw new Error(`Failed to parse registry JSON at ${filePath}: ${msg}`, {
+      cause: err,
+    });
   }
 
   const result = WorkspaceRegistrySchema.safeParse(raw);
diff --git a/src/reporter/persist.ts b/src/reporter/persist.ts
index ea182c7..201fc07 100644
--- a/src/reporter/persist.ts
+++ b/src/reporter/persist.ts
@@ -132,7 +132,7 @@ export function loadLastRun(): PersistedRun | null {
     raw = JSON.parse(fs.readFileSync(filePath, "utf8")) as unknown;
   } catch (err) {
     const msg = err instanceof Error ? err.message : String(err);
-    throw new Error(`Failed to parse last-run.json: ${msg}`);
+    throw new Error(`Failed to parse last-run.json: ${msg}`, { cause: err });
   }
 
   return validatePersistedRun(raw);