diff --git a/scripts/seed-test-data.rb b/scripts/seed-test-data.rb
index 353a0e4..bada6b9 100644
--- a/scripts/seed-test-data.rb
+++ b/scripts/seed-test-data.rb
@@ -32,6 +32,7 @@ test_project.description = 'Dedicated test project for openproject-mcp companion
 test_project.public = true
 test_project.workspace_type = 'project' if test_project.respond_to?(:workspace_type=)
 test_project.types = Type.all if Type.any?
+test_project.enabled_module_names = OpenProject::AccessControl.available_project_modules if defined?(OpenProject::AccessControl)
 test_project.save!(validate: false)
 puts "[Seeder] Ensured project 'MCP Test Project' (ID: #{test_project.id}, identifier: #{test_project.identifier})."
 
diff --git a/scripts/seed.sh b/scripts/seed.sh
index acc1d4b..11eea27 100755
--- a/scripts/seed.sh
+++ b/scripts/seed.sh
@@ -52,10 +52,8 @@ OPENPROJECT_API_KEY=${API_KEY}
 OPENPROJECT_TEST_PROJECT=${PROJECT_IDENTIFIER}
 EOF
 
-# Also update .env.local if not present or populate key
-if [ ! -f "${ROOT_DIR}/.env.local" ]; then
-  cp "${ROOT_DIR}/.env.test" "${ROOT_DIR}/.env.local"
-fi
+# Also update .env.local
+cp "${ROOT_DIR}/.env.test" "${ROOT_DIR}/.env.local"
 
 echo ""
 echo "[seed.sh] Success! Test environment configured."
diff --git a/src/services/helper.ts b/src/services/helper.ts
index 8963b87..cf23b3a 100644
--- a/src/services/helper.ts
+++ b/src/services/helper.ts
@@ -12,3 +12,24 @@ import type { OpenProjectClient } from "../client/api-client.ts";
 export function resolveClient(client?: OpenProjectClient): OpenProjectClient {
   return client ?? getRequestContext().client;
 }
+
+/**
+ * Resolves a numeric project ID from either a number or string identifier.
+ * If the value is a number or integer string, returns the parsed integer.
+ * Otherwise, queries the OpenProject API for the project by identifier to get its numeric ID.
+ */
+export async function resolveProjectId(
+  projectId: number | string,
+  client?: OpenProjectClient
+): Promise<number> {
+  if (typeof projectId === "number") {
+    return projectId;
+  }
+  const trimmed = projectId.trim();
+  if (/^\d+$/.test(trimmed)) {
+    return parseInt(trimmed, 10);
+  }
+  const opClient = resolveClient(client);
+  const response = await opClient.get<{ id: number }>(`projects/${encodeURIComponent(trimmed)}`);
+  return response.id;
+}
diff --git a/src/services/queries.ts b/src/services/queries.ts
index 1885530..fa2a7f3 100644
--- a/src/services/queries.ts
+++ b/src/services/queries.ts
@@ -2,7 +2,7 @@
  * Queries Domain Service.
  */
 
-import type { OpenProjectClient } from "../client/api-client.ts";
+import { OpenProjectNotFoundError, type OpenProjectClient } from "../client/api-client.ts";
 import {
   normalizeQuery,
   normalizeQuerySummary,
@@ -17,7 +17,7 @@ import type {
   QuerySummary,
   WorkPackageSummary,
 } from "../client/types.ts";
-import { resolveClient } from "./helper.ts";
+import { resolveClient, resolveProjectId } from "./helper.ts";
 
 export interface ListQueriesParams {
   projectId?: number | string;
@@ -43,9 +43,10 @@ export async function listQueries(
   if (params?.pageSize !== undefined) query.pageSize = params.pageSize;
   if (params?.offset !== undefined) query.offset = params.offset;
 
-  if (params?.projectId !== undefined) {
+  if (params?.projectId !== undefined && params.projectId !== "") {
+    const numericProjectId = await resolveProjectId(params.projectId, opClient);
     query.filters = JSON.stringify([
-      { project: { operator: "=", values: [String(params.projectId)] } },
+      { project: { operator: "=", values: [String(numericProjectId)] } },
     ]);
   }
 
@@ -79,9 +80,22 @@ export async function getQueryResults(
   if (params?.pageSize !== undefined) query.pageSize = params.pageSize;
   if (params?.offset !== undefined) query.offset = params.offset;
 
-  const response = await opClient.get<HalCollection<HalResource>>(
-    `queries/${id}/results`,
-    query
-  );
-  return unpackCollection(response, normalizeWorkPackageSummary);
+  try {
+    const response = await opClient.get<HalCollection<HalResource>>(
+      `queries/${id}/results`,
+      query
+    );
+    return unpackCollection(response, normalizeWorkPackageSummary);
+  } catch (err) {
+    if (err instanceof OpenProjectNotFoundError) {
+      // In OpenProject API v3, query results endpoint is dynamically linked in query._links.results.href
+      const queryDetail = await opClient.get<HalResource>(`queries/${id}`);
+      const resultsHref = queryDetail._links?.results?.href;
+      if (typeof resultsHref === "string" && resultsHref.length > 0) {
+        const response = await opClient.get<HalCollection<HalResource>>(resultsHref, query);
+        return unpackCollection(response, normalizeWorkPackageSummary);
+      }
+    }
+    throw err;
+  }
 }
diff --git a/src/services/work-packages.ts b/src/services/work-packages.ts
index 67f6203..6885b06 100644
--- a/src/services/work-packages.ts
+++ b/src/services/work-packages.ts
@@ -17,7 +17,7 @@ import type {
   WorkPackageFilterParams,
   WorkPackageSummary,
 } from "../client/types.ts";
-import { resolveClient } from "./helper.ts";
+import { resolveClient, resolveProjectId } from "./helper.ts";
 
 export interface ListWorkPackagesParams extends WorkPackageFilterParams {
   pageSize?: number;
@@ -46,7 +46,12 @@ export async function listWorkPackages(
   if (params?.sortBy !== undefined) query.sortBy = params.sortBy;
 
   if (params) {
-    const filters = buildWorkPackageFilters(params);
+    let filterParams = params;
+    if (params.projectId !== undefined && params.projectId !== "") {
+      const numericProjectId = await resolveProjectId(params.projectId, opClient);
+      filterParams = { ...params, projectId: numericProjectId };
+    }
+    const filters = buildWorkPackageFilters(filterParams);
     if (filters.length > 0) {
       query.filters = JSON.stringify(filters);
     }