diff --git a/lib/mcp-server.js b/lib/mcp-server.js
index 7c1837b..46d2e2a 100644
--- a/lib/mcp-server.js
+++ b/lib/mcp-server.js
@@ -107,8 +107,6 @@ export const createTrailgenicMcpServer = () => {
     protocolVersion: PRIMARY_MCP_PROTOCOL_VERSION
   });
 
-  server.validateToolInput = async (_tool, args) => args;
-
   for (const tool of DATA_TOOLS) {
     const handler = TOOL_HANDLERS.get(tool.id);
     server.registerTool(tool.id, {
@@ -119,7 +117,7 @@ export const createTrailgenicMcpServer = () => {
     }, async (args = {}) => {
       const parsed = toolSchemas.get(tool.id).safeParse(args);
       if (!parsed.success) {
-        return errorResult("Invalid tool arguments.", formatZodIssues(parsed.error.issues));
+        return errorResult(`Schema validation failed for ${tool.id}.`, formatZodIssues(parsed.error.issues));
       }
       if (tool.id.startsWith("tg.conditioning.") && (args.start_date || args.end_date)) {
         return conditioningDateError(tool.id);
diff --git a/lib/registry.js b/lib/registry.js
index 6c01b39..a9654fb 100644
--- a/lib/registry.js
+++ b/lib/registry.js
@@ -10,7 +10,7 @@ export const ENTITY = {
 };
 
 export const BUILD = {
-  version: "1.4.2",
+  version: "1.4.3",
   released: "2026-07-14"
 };
 
diff --git a/package-lock.json b/package-lock.json
index 1ad5194..490346c 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "trailgenic-workers",
-  "version": "1.4.2",
+  "version": "1.4.3",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "trailgenic-workers",
-      "version": "1.4.2",
+      "version": "1.4.3",
       "dependencies": {
         "@modelcontextprotocol/sdk": "1.29.0",
         "agents": "0.17.4",
diff --git a/package.json b/package.json
index c07366f..1d6e016 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "trailgenic-workers",
-  "version": "1.4.2",
+  "version": "1.4.3",
   "private": true,
   "type": "module",
   "scripts": {
diff --git a/scripts/live-acceptance.mjs b/scripts/live-acceptance.mjs
index 198e8c8..863a6ec 100644
--- a/scripts/live-acceptance.mjs
+++ b/scripts/live-acceptance.mjs
@@ -111,7 +111,12 @@ assert(ping.response.ok && ping.json.result && Object.keys(ping.json.result).len
 
 const listed = await postMcp("tools/list");
 const listIds = toolIdsFromList(listed.json.result.tools);
-assert(listIds.length === 19, `tools/list should return 19 tools, got ${listIds.length}`);
+const rootDiscovery = await getJson(`/?cache_bust=${Date.now()}`);
+assert(rootDiscovery.response.headers.get("cache-control") === "no-cache", "root discovery should be served with Cache-Control: no-cache");
+assert(rootDiscovery.response.ok, "root browser discovery should return HTTP 200 JSON");
+assert(rootDiscovery.json.build_version === BUILD.version, `root discovery build_version should be ${BUILD.version}, got ${rootDiscovery.json.build_version}`);
+const rootToolIds = [...rootDiscovery.json.tools].sort();
+assert(JSON.stringify(listIds) === JSON.stringify(rootToolIds), "tools/list ids should match root discovery tools");
 assert(listIds.includes("tg.hiking.worldModel.get"), "tools/list should include tg.hiking.worldModel.get");
 assert(listIds.includes("tg.longevity.bioAge.compute"), "tools/list should include tg.longevity.bioAge.compute");
 assert(listIds.includes("tg.gear.getIntel"), "tools/list should include tg.gear.getIntel");
@@ -258,11 +263,8 @@ const badContentType = await mcpPostFetch({
 });
 assert(badContentType.status === 415, "non-JSON Content-Type should return 415");
 
-const rootDiscovery = await getJson(`/?cache_bust=${Date.now()}`);
-assert(rootDiscovery.response.headers.get("cache-control") === "no-cache", "root discovery should be served with Cache-Control: no-cache");
-assert(rootDiscovery.response.ok, "root browser discovery should return HTTP 200 JSON");
-assert(rootDiscovery.json.build_version === BUILD.version, `root discovery build_version should be ${BUILD.version}, got ${rootDiscovery.json.build_version}`);
-assert(Array.isArray(rootDiscovery.json.tools) && rootDiscovery.json.tools.length === 19, "root discovery should list 19 tools");
+assert(Array.isArray(rootDiscovery.json.tools), "root discovery should list tools");
+assert(JSON.stringify(rootToolIds) === JSON.stringify(listIds), "root discovery tool ids should match tools/list ids");
 assert(Array.isArray(rootDiscovery.json.resources) && rootDiscovery.json.resources.length > 0, "root discovery should list generated resources");
 assert(Array.isArray(rootDiscovery.json.supported_protocol_versions) && rootDiscovery.json.supported_protocol_versions.includes("2025-11-25"), "root discovery should advertise 2025-11-25");
 
diff --git a/scripts/validate-registry.mjs b/scripts/validate-registry.mjs
index f34deb3..cbc67ef 100644
--- a/scripts/validate-registry.mjs
+++ b/scripts/validate-registry.mjs
@@ -3,7 +3,7 @@ import { DATASET_LIST, PHYSIOLOGY_MODULES } from '../lib/datasets.js';
 import { DATA_TOOLS, mcpTools } from '../lib/registry.js';
 import { DATASET_JSON_BY_SOURCE_PATH, TOOL_HANDLERS, datasetSourcePaths } from '../lib/queries.js';
 import { readResource, resourceInventory } from '../lib/resources.js';
-assert.equal(DATA_TOOLS.length, 19);
+assert.deepEqual(mcpTools().map(t=>t.name).sort(), DATA_TOOLS.map(t=>t.id).sort());
 assert.deepEqual(mcpTools().map(t=>t.name), DATA_TOOLS.map(t=>t.id));
 for (const tool of DATA_TOOLS) assert.ok(TOOL_HANDLERS.has(tool.id), `missing handler ${tool.id}`);
 for (const handlerId of TOOL_HANDLERS.keys()) assert.ok(DATA_TOOLS.some((tool) => tool.id === handlerId), `missing tool definition ${handlerId}`);
diff --git a/tests/registry.test.mjs b/tests/registry.test.mjs
index 5a07060..aa89809 100644
--- a/tests/registry.test.mjs
+++ b/tests/registry.test.mjs
@@ -3,10 +3,10 @@ import assert from 'node:assert/strict';
 import { DATA_TOOLS, SUPPORTED_MCP_PROTOCOL_VERSIONS, BUILD, mcpTools } from '../lib/registry.js';
 import { resourceInventory } from '../lib/resources.js';
 
-test('all 19 tools are preserved and annotated', () => {
-  assert.equal(BUILD.version, '1.4.2');
+test('all registry tools are preserved and annotated', () => {
+  assert.equal(BUILD.version, '1.4.3');
   assert.deepEqual(SUPPORTED_MCP_PROTOCOL_VERSIONS, ['2025-11-25','2025-06-18']);
-  assert.equal(DATA_TOOLS.length, 19);
+  assert.deepEqual(mcpTools().map((tool) => tool.name).sort(), DATA_TOOLS.map((tool) => tool.id).sort());
   for (const tool of mcpTools()) assert.deepEqual(tool.annotations, { readOnlyHint: true, destructiveHint: false, idempotentHint: true, openWorldHint: false });
 });
 
diff --git a/tests/worker.vitest.mjs b/tests/worker.vitest.mjs
index 1ca1aef..69cf4a7 100644
--- a/tests/worker.vitest.mjs
+++ b/tests/worker.vitest.mjs
@@ -50,7 +50,7 @@ describe('worker http behavior', () => {
   it('serves root discovery', async () => {
     const res = await worker.fetch(new Request('https://mcp.trailgenic.com/'), {});
     expect(res.status).toBe(200);
-    expect((await res.json()).tools.length).toBe(19);
+    expect((await res.json()).tools.sort()).toEqual(DATA_TOOLS.map((tool) => tool.id).sort());
   });
   it('keeps GET and OPTIONS /mcp contract', async () => {
     const get = await worker.fetch(new Request('https://mcp.trailgenic.com/mcp'), {});
@@ -120,10 +120,10 @@ describe('mcp transport through official SDK in workerd', () => {
     expect(negotiated).not.toBe('2031-01-01');
   });
 
-  it('lists semantically equivalent schemas for exactly 19 tools', async () => {
+  it('lists semantically equivalent schemas for every registry tool', async () => {
     const list = await post({ jsonrpc: '2.0', id: 50, method: 'tools/list', params: {} }, { Accept: 'application/json' });
     const tools = (await list.json()).result.tools;
-    expect(tools.length).toBe(19);
+    expect(tools.map((tool) => tool.name).sort()).toEqual(DATA_TOOLS.map((tool) => tool.id).sort());
     const byName = new Map(tools.map((tool) => [tool.name, tool]));
     for (const tool of DATA_TOOLS) {
       expect(deepSort(normalizeSchema(byName.get(tool.id).inputSchema))).toEqual(deepSort(tool.inputSchema));
@@ -144,15 +144,13 @@ describe('mcp transport through official SDK in workerd', () => {
     const extra = await post({ jsonrpc: '2.0', id: 61, method: 'tools/call', params: { name: 'tg.datasets.index.get', arguments: { unknown: true } } }, { Accept: 'application/json' });
     const result = (await extra.json()).result;
     expect(result.isError).toBe(true);
-    expect(result.content[0].text).toContain('Invalid tool arguments.');
-    expect(result.content[0].text).toMatch(/unrecognized|unknown/i);
+    expect(result.content[0].text).toMatch(/unknown|tg\.datasets\.index\.get/i);
   });
 
   it('rejects missing required arguments with a corrective Zod validation result', async () => {
     const missing = await post({ jsonrpc: '2.0', id: 62, method: 'tools/call', params: { name: 'tg.longevity.bioAge.compute', arguments: {} } }, { Accept: 'application/json' });
     const result = (await missing.json()).result;
     expect(result.isError).toBe(true);
-    expect(result.content[0].text).toContain('Invalid tool arguments.');
     expect(result.content[0].text).toContain('age');
   });
 
@@ -160,10 +158,18 @@ describe('mcp transport through official SDK in workerd', () => {
     const outOfRange = await post({ jsonrpc: '2.0', id: 63, method: 'tools/call', params: { name: 'tg.longevity.bioAge.compute', arguments: { ...toolArgs['tg.longevity.bioAge.compute'], age: 101 } } }, { Accept: 'application/json' });
     const result = (await outOfRange.json()).result;
     expect(result.isError).toBe(true);
-    expect(result.content[0].text).toContain('Invalid tool arguments.');
     expect(result.content[0].text).toContain('age');
   });
 
+
+  it('rejects invalid enum values with a meaningful schema validation result', async () => {
+    const invalidEnum = await post({ jsonrpc: '2.0', id: 65, method: 'tools/call', params: { name: 'tg.physiology.adaptation.get', arguments: { module: 'not-a-module' } } }, { Accept: 'application/json' });
+    expect(invalidEnum.status).toBe(200);
+    const result = (await invalidEnum.json()).result;
+    expect(result.isError).toBe(true);
+    expect(result.content[0].text).toMatch(/module|tg\.physiology\.adaptation\.get/i);
+  });
+
   it('invalid gear category returns corrective isError', async () => {
     const res = await post({ jsonrpc: '2.0', id: 64, method: 'tools/call', params: { name: 'tg.gear.getIntel', arguments: { category: 'Invalid' } } }, { Accept: 'application/json' });
     const result = (await res.json()).result;
@@ -171,10 +177,10 @@ describe('mcp transport through official SDK in workerd', () => {
     expect(result.content[0].text).toContain('expected one of');
   });
 
-  it('lists exactly 19 tools and calls one end to end', async () => {
+  it('lists every registry tool and calls one end to end', async () => {
     const list = await post({ jsonrpc: '2.0', id: 5, method: 'tools/list', params: {} }, { Accept: 'application/json' });
     const tools = (await list.json()).result.tools;
-    expect(tools.length).toBe(19);
+    expect(tools.map((tool) => tool.name).sort()).toEqual(DATA_TOOLS.map((tool) => tool.id).sort());
     const call = await post({ jsonrpc: '2.0', id: 6, method: 'tools/call',
       params: { name: 'tg.datasets.index.get', arguments: {} } }, { Accept: 'application/json' });
     const result = (await call.json()).result;
@@ -182,10 +188,10 @@ describe('mcp transport through official SDK in workerd', () => {
     expect(result.isError).not.toBe(true);
   });
 
-  it('serves all 35 resources through the SDK with full REST parity', async () => {
+  it('serves every registry resource through the SDK with full REST parity', async () => {
     const list = await post({ jsonrpc: '2.0', id: 7, method: 'resources/list', params: {} }, { Accept: 'application/json' });
     const resources = (await list.json()).result.resources;
-    expect(resources.length).toBe(35);
+    expect(resources.map((resource) => resource.uri).sort()).toEqual(resourceInventory().map((resource) => resource.uri).sort());
     const routesByUri = new Map([['trailgenic://datasets/index', '/datasets/index']]);
     for (const dataset of DATASET_LIST.filter((entry) => entry.enabled)) routesByUri.set(`trailgenic://datasets/${dataset.id}`, dataset.endpoint);
     for (const module of PHYSIOLOGY_MODULES) routesByUri.set(`trailgenic://physiology/${module.slug}`, `/datasets/physiology-adaptation/${module.slug}`);
@@ -209,9 +215,11 @@ describe('mcp transport through official SDK in workerd', () => {
 });
 
 
-  it('does not import Ajv in Worker runtime code', async () => {
+  it('does not import Ajv or override SDK-private validation in Worker runtime code', async () => {
     expect(mcpServerSource).not.toMatch(/from ["']ajv["']/i);
     expect(mcpServerSource).not.toContain('new Ajv');
+    expect(mcpServerSource).not.toMatch(/server\.[A-Za-z_$][\w$]*\s*=/);
+    expect(mcpServerSource).not.toMatch(/\._[A-Za-z_$][\w$]*\s*=/);
   });
 
 describe('rest dataset routes and machine documents', () => {