diff --git a/packages/backend/src/connectors/parsers/openapi-3.1-normalizer.spec.ts b/packages/backend/src/connectors/parsers/openapi-3.1-normalizer.spec.ts
index e16056fa..d0b010d3 100644
--- a/packages/backend/src/connectors/parsers/openapi-3.1-normalizer.spec.ts
+++ b/packages/backend/src/connectors/parsers/openapi-3.1-normalizer.spec.ts
@@ -183,6 +183,27 @@ describe('normalizeOpenApi31', () => {
     expect(result).toBe(spec);
   });
 
+  it('strips info.summary (3.1-only field forbidden by 3.0 schema)', () => {
+    const spec: any = {
+      openapi: '3.1.0',
+      info: { title: 'X', summary: 'A short summary', version: '1' },
+      paths: {},
+    };
+    normalizeOpenApi31(spec);
+    expect(spec.info.summary).toBeUndefined();
+    expect(spec.info.title).toBe('X');
+  });
+
+  it('leaves info untouched when there is no summary field', () => {
+    const spec: any = {
+      openapi: '3.1.0',
+      info: { title: 'X', version: '1' },
+      paths: {},
+    };
+    normalizeOpenApi31(spec);
+    expect(spec.info).toEqual({ title: 'X', version: '1' });
+  });
+
   it('relabels openapi: 3.1.x to 3.0.3 so swagger-parser accepts it', () => {
     const spec: any = { openapi: '3.1.0', info: { title: 'X', version: '1' }, paths: {} };
     normalizeOpenApi31(spec);
diff --git a/packages/backend/src/connectors/parsers/openapi-3.1-normalizer.ts b/packages/backend/src/connectors/parsers/openapi-3.1-normalizer.ts
index fe781a0f..9be4ec5c 100644
--- a/packages/backend/src/connectors/parsers/openapi-3.1-normalizer.ts
+++ b/packages/backend/src/connectors/parsers/openapi-3.1-normalizer.ts
@@ -35,6 +35,14 @@ export function normalizeOpenApi31(spec: unknown): unknown {
     if (typeof obj.openapi === 'string' && obj.openapi.startsWith('3.1')) {
       obj.openapi = '3.0.3';
     }
+    // 3.1 added info.summary; 3.0 forbids it. We don't currently call the
+    // schema validator on 3.1 specs (we use dereference()), so this is a
+    // defensive strip: it keeps the relabeled document safe if any future
+    // codepath does call validate().
+    const info = obj.info;
+    if (info && typeof info === 'object' && 'summary' in (info as Record<string, unknown>)) {
+      delete (info as Record<string, unknown>).summary;
+    }
   }
   return spec;
 }
diff --git a/packages/backend/src/mcp-server/mcp-server.service.spec.ts b/packages/backend/src/mcp-server/mcp-server.service.spec.ts
new file mode 100644
index 00000000..e42a5515
--- /dev/null
+++ b/packages/backend/src/mcp-server/mcp-server.service.spec.ts
@@ -0,0 +1,110 @@
+import { z } from 'zod';
+import { McpServerService } from './mcp-server.service';
+
+/**
+ * Direct unit coverage for the private `jsonSchemaToZod` helper. We bypass the
+ * Nest DI by instantiating with `Object.create` and reaching into the method
+ * — full controller-level tests would need Prisma, ConfigService, and the
+ * @rekog/mcp-nest registry, which is overkill for a pure transformer.
+ */
+function makeSchema(jsonSchema: Record<string, unknown>): z.ZodTypeAny {
+  const svc = Object.create(McpServerService.prototype);
+  return (svc as any).jsonSchemaToZod(jsonSchema);
+}
+
+describe('McpServerService.jsonSchemaToZod', () => {
+  it('accepts a numeric integer arg sent as a string ("5") and returns a number', () => {
+    const schema = makeSchema({
+      type: 'object',
+      properties: { top_k: { type: 'integer', description: 'how many' } },
+      required: ['top_k'],
+    });
+    const parsed = schema.parse({ top_k: '5' });
+    expect(parsed).toEqual({ top_k: 5 });
+    expect(typeof (parsed as any).top_k).toBe('number');
+  });
+
+  it('still rejects a non-numeric string for an integer field', () => {
+    const schema = makeSchema({
+      type: 'object',
+      properties: { top_k: { type: 'integer' } },
+      required: ['top_k'],
+    });
+    expect(() => schema.parse({ top_k: 'abc' })).toThrow();
+  });
+
+  it('accepts "1.5" for a number type', () => {
+    const schema = makeSchema({
+      type: 'object',
+      properties: { score: { type: 'number' } },
+      required: ['score'],
+    });
+    expect(schema.parse({ score: '1.5' })).toEqual({ score: 1.5 });
+  });
+
+  it('rejects a float "1.5" for an integer type', () => {
+    const schema = makeSchema({
+      type: 'object',
+      properties: { count: { type: 'integer' } },
+      required: ['count'],
+    });
+    expect(() => schema.parse({ count: '1.5' })).toThrow();
+  });
+
+  it('coerces "true" / "false" strings to boolean (well, anything truthy → true)', () => {
+    const schema = makeSchema({
+      type: 'object',
+      properties: { active: { type: 'boolean' } },
+      required: ['active'],
+    });
+    // z.coerce.boolean treats any non-empty string as true. That matches how
+    // most MCP clients render checkbox state, but the consumer should be
+    // aware that "false" coerces to true.
+    expect(schema.parse({ active: 'true' })).toEqual({ active: true });
+    expect(schema.parse({ active: true })).toEqual({ active: true });
+    expect(schema.parse({ active: false })).toEqual({ active: false });
+    expect(schema.parse({ active: 0 })).toEqual({ active: false });
+  });
+
+  it('keeps an enum string field strict (no coercion)', () => {
+    const schema = makeSchema({
+      type: 'object',
+      properties: { mode: { type: 'string', enum: ['fast', 'slow'] } },
+      required: ['mode'],
+    });
+    expect(schema.parse({ mode: 'fast' })).toEqual({ mode: 'fast' });
+    expect(() => schema.parse({ mode: 'unknown' })).toThrow();
+  });
+
+  it('coerces date-time strings to Date instances', () => {
+    const schema = makeSchema({
+      type: 'object',
+      properties: { from: { type: 'string', format: 'date-time' } },
+      required: ['from'],
+    });
+    const parsed: any = schema.parse({ from: '2026-05-12T09:00:00Z' });
+    expect(parsed.from).toBeInstanceOf(Date);
+  });
+
+  it('marks non-required fields as optional', () => {
+    const schema = makeSchema({
+      type: 'object',
+      properties: {
+        a: { type: 'string' },
+        b: { type: 'integer' },
+      },
+      required: ['a'],
+    });
+    expect(schema.parse({ a: 'x' })).toEqual({ a: 'x' });
+    expect(schema.parse({ a: 'x', b: '7' })).toEqual({ a: 'x', b: 7 });
+  });
+
+  it('passes plain strings through unchanged', () => {
+    const schema = makeSchema({
+      type: 'object',
+      properties: { q: { type: 'string' } },
+      required: ['q'],
+    });
+    expect(schema.parse({ q: 'Domoferm' })).toEqual({ q: 'Domoferm' });
+  });
+});
diff --git a/packages/backend/src/mcp-server/mcp-server.service.ts b/packages/backend/src/mcp-server/mcp-server.service.ts
index 633bef09..54bba8bd 100644
--- a/packages/backend/src/mcp-server/mcp-server.service.ts
+++ b/packages/backend/src/mcp-server/mcp-server.service.ts
@@ -309,7 +309,14 @@ export class McpServerService implements OnModuleInit {
 
   /**
    * Convert a JSON Schema object to a Zod schema for the MCP library.
-   * Handles the common types used in tool parameters.
+   *
+   * Numeric / boolean / date fields use `z.coerce.*` rather than `z.number()`
+   * etc. Several MCP clients (and AI tool-call layers in general) serialize
+   * every argument as a string before transport, so a tool with a numeric
+   * parameter would otherwise reject perfectly valid calls like
+   * `{ "top_k": "5" }` with "expected number, received string". Coercion
+   * still rejects non-numeric strings (e.g. `"abc"`), so we keep the
+   * validation signal where it matters.
    */
   private jsonSchemaToZod(schema: Record<string, unknown>): any {
     const properties = schema?.properties as Record<string, any> | undefined;
@@ -323,16 +330,24 @@ export class McpServerService implements OnModuleInit {
 
       switch (prop.type) {
         case 'string':
-          zodType = prop.enum
-            ? z.enum(prop.enum as [string, ...string[]])
-            : z.string();
+          if (prop.enum) {
+            zodType = z.enum(prop.enum as [string, ...string[]]);
+          } else if (prop.format === 'date-time' || prop.format === 'date') {
+            // Accept ISO date strings and Date-coercible inputs.
+            zodType = z.coerce.date();
+          } else {
+            zodType = z.string();
+          }
           break;
-        case 'number':
         case 'integer':
-          zodType = z.number();
+          // .int() rejects floats; coerce handles string→number first.
+          zodType = z.coerce.number().int();
+          break;
+        case 'number':
+          zodType = z.coerce.number();
           break;
         case 'boolean':
-          zodType = z.boolean();
+          zodType = z.coerce.boolean();
           break;
         case 'array':
           zodType = z.array(z.any());