diff --git a/src/agents/claude-agent-sdk/sdk-agent-runtime.ts b/src/agents/claude-agent-sdk/sdk-agent-runtime.ts
index fe5294893..8360f8bba 100644
--- a/src/agents/claude-agent-sdk/sdk-agent-runtime.ts
+++ b/src/agents/claude-agent-sdk/sdk-agent-runtime.ts
@@ -214,15 +214,6 @@ export function createCcSdkAgentRuntime(context?: CcSdkAgentRuntimeContext): Age
         ? `${params.provider ?? "anthropic"}/${params.model}`
         : (ccsdkOpts.modelTiers?.sonnet ?? context?.ccsdkConfig?.models?.sonnet ?? "default");
 
-      log.debug("Starting CCSDK Agent session", {
-        sessionId: params.sessionId,
-        runId: params.runId,
-        provider: providerConfig.name,
-        model: effectiveModel,
-        agentId,
-        thinkLevel: params.thinkLevel,
-      });
-
       // Load conversation history from session file if not provided
       let conversationHistory = context?.conversationHistory;
       if (!conversationHistory && params.sessionFile) {
@@ -275,12 +266,6 @@ export function createCcSdkAgentRuntime(context?: CcSdkAgentRuntimeContext): Age
       // Combine built-in tools with client tools
       const tools: AnyAgentTool[] = [...builtInTools, ...clientToolsConverted];
 
-      log.debug("Built tools for CCSDK run", {
-        builtInCount: builtInTools.length,
-        clientToolCount: clientToolsConverted.length,
-        totalCount: tools.length,
-      });
-
       // Resolve CCSDK config directory for this agent's session storage.
       // This ensures Moltbot sessions are stored separately from CLI sessions.
       const ccsdkConfigDir = resolveCcSdkConfigDirForAgent(agentId);
diff --git a/src/agents/claude-agent-sdk/sdk-runner.ts b/src/agents/claude-agent-sdk/sdk-runner.ts
index 8f1693b53..8121839e3 100644
--- a/src/agents/claude-agent-sdk/sdk-runner.ts
+++ b/src/agents/claude-agent-sdk/sdk-runner.ts
@@ -630,12 +630,12 @@ export async function runSdkAgent(params: SdkRunnerParams): Promise<SdkRunnerRes
       };
     }
 
-    log.debug(
-      `Bridged ${bridgeResult.toolCount} tools to MCP server "${mcpServerName}"` +
-        (bridgeResult.skippedTools.length > 0
-          ? ` (skipped: ${bridgeResult.skippedTools.join(", ")})`
-          : ""),
-    );
+    // log.debug(
+    //   `Exposed ${bridgeResult.toolCount} tools to MCP server "${mcpServerName}"` +
+    //     (bridgeResult.skippedTools.length > 0
+    //       ? ` (skipped: ${bridgeResult.skippedTools.join(", ")})`
+    //       : ""),
+    // );
   }
 
   // -------------------------------------------------------------------------
diff --git a/src/agents/claude-agent-sdk/tool-bridge.test.ts b/src/agents/claude-agent-sdk/tool-bridge.test.ts
index 2a84c5289..4072aebb1 100644
--- a/src/agents/claude-agent-sdk/tool-bridge.test.ts
+++ b/src/agents/claude-agent-sdk/tool-bridge.test.ts
@@ -119,7 +119,8 @@ describe("tool-bridge", () => {
       expect(typeof zodSchema.parse).toBe("function");
       expect(typeof zodSchema.safeParse).toBe("function");
       expect(typeof zodSchema.safeParseAsync).toBe("function");
-      expect(zodSchema._def.typeName).toBe("ZodObject");
+      // Zod v4 Mini uses _zod instead of _def
+      expect((zodSchema as any)._zod).toBeDefined();
     });
 
     it("parse returns data for valid input", () => {
@@ -645,4 +646,182 @@ describe("tool-bridge", () => {
       expect(result.skippedTools).toContain("bad_tool");
     });
   });
+
+  describe("tool call error handling", () => {
+    const mockExtra = { signal: new AbortController().signal };
+
+    it("includes tool name in error message when tool throws", async () => {
+      const mockExecute = vi.fn().mockRejectedValue(new Error("Database connection failed"));
+
+      const tool = {
+        name: "database-query",
+        execute: mockExecute,
+      } as unknown as AnyAgentTool;
+
+      const handler = wrapToolHandler(tool);
+      const result = await handler({ query: "SELECT *" }, mockExtra);
+
+      expect(result.isError).toBe(true);
+      expect(result.content[0].type).toBe("text");
+      expect((result.content[0] as { text: string }).text).toContain("database_query");
+      expect((result.content[0] as { text: string }).text).toContain("Database connection failed");
+    });
+
+    it("handles non-Error thrown values", async () => {
+      const mockExecute = vi.fn().mockRejectedValue("string error message");
+
+      const tool = {
+        name: "string-error-tool",
+        execute: mockExecute,
+      } as unknown as AnyAgentTool;
+
+      const handler = wrapToolHandler(tool);
+      const result = await handler({}, mockExtra);
+
+      expect(result.isError).toBe(true);
+      expect((result.content[0] as { text: string }).text).toContain("string error message");
+    });
+
+    it("handles undefined/null thrown values", async () => {
+      const mockExecute = vi.fn().mockRejectedValue(undefined);
+
+      const tool = {
+        name: "undefined-error-tool",
+        execute: mockExecute,
+      } as unknown as AnyAgentTool;
+
+      const handler = wrapToolHandler(tool);
+      const result = await handler({}, mockExtra);
+
+      expect(result.isError).toBe(true);
+      expect(result.content.length).toBeGreaterThan(0);
+    });
+
+    it("converts tool_error blocks from result to MCP error format", () => {
+      const result: AgentToolResult<unknown> = {
+        content: [
+          { type: "tool_error", error: "Validation failed: missing required field 'name'" },
+        ],
+      };
+
+      const mcpResult = convertToolResult(result);
+
+      expect(mcpResult.isError).toBe(true);
+      expect(mcpResult.content).toHaveLength(1);
+      expect((mcpResult.content[0] as { text: string }).text).toBe(
+        "Validation failed: missing required field 'name'",
+      );
+    });
+
+    it("preserves error details from multiple error blocks", () => {
+      const result: AgentToolResult<unknown> = {
+        content: [
+          { type: "tool_error", error: "Error 1: Invalid input" },
+          { type: "tool_error", error: "Error 2: Permission denied" },
+        ],
+      };
+
+      const mcpResult = convertToolResult(result);
+
+      expect(mcpResult.isError).toBe(true);
+      expect(mcpResult.content).toHaveLength(2);
+    });
+
+    it("marks result as error when any block has error field", () => {
+      const result: AgentToolResult<unknown> = {
+        content: [
+          { type: "text", text: "Partial success" },
+          { type: "warning", error: "But something went wrong" },
+        ],
+      };
+
+      const mcpResult = convertToolResult(result);
+
+      expect(mcpResult.isError).toBe(true);
+    });
+  });
+
+  describe("Zod schema conversion", () => {
+    it("converts TypeBox string property to Zod string", () => {
+      const typeboxSchema = Type.Object({
+        name: Type.String(),
+      });
+
+      const zodSchema = createZodCompatibleSchema(typeboxSchema);
+
+      // Should successfully parse valid input
+      const parseResult = zodSchema.safeParse({ name: "test" });
+      expect(parseResult.success).toBe(true);
+    });
+
+    it("converts TypeBox number property to Zod number", () => {
+      const typeboxSchema = Type.Object({
+        count: Type.Number(),
+      });
+
+      const zodSchema = createZodCompatibleSchema(typeboxSchema);
+
+      const parseResult = zodSchema.safeParse({ count: 42 });
+      expect(parseResult.success).toBe(true);
+    });
+
+    it("converts TypeBox boolean property to Zod boolean", () => {
+      const typeboxSchema = Type.Object({
+        active: Type.Boolean(),
+      });
+
+      const zodSchema = createZodCompatibleSchema(typeboxSchema);
+
+      const parseResult = zodSchema.safeParse({ active: true });
+      expect(parseResult.success).toBe(true);
+    });
+
+    it("converts TypeBox array property to Zod array", () => {
+      const typeboxSchema = Type.Object({
+        items: Type.Array(Type.String()),
+      });
+
+      const zodSchema = createZodCompatibleSchema(typeboxSchema);
+
+      const parseResult = zodSchema.safeParse({ items: ["a", "b", "c"] });
+      expect(parseResult.success).toBe(true);
+    });
+
+    it("converts TypeBox optional property to Zod optional", () => {
+      const typeboxSchema = Type.Object({
+        required: Type.String(),
+        optional: Type.Optional(Type.String()),
+      });
+
+      const zodSchema = createZodCompatibleSchema(typeboxSchema);
+
+      // Should work without optional field
+      const parseResult = zodSchema.safeParse({ required: "value" });
+      expect(parseResult.success).toBe(true);
+    });
+
+    it("rejects invalid input with Zod validation errors", () => {
+      const typeboxSchema = Type.Object({
+        name: Type.String(),
+        count: Type.Number(),
+      });
+
+      const zodSchema = createZodCompatibleSchema(typeboxSchema);
+
+      // Pass wrong types
+      const parseResult = zodSchema.safeParse({ name: 123, count: "not a number" });
+      expect(parseResult.success).toBe(false);
+    });
+
+    it("has _zod property for MCP SDK compatibility", () => {
+      const typeboxSchema = Type.Object({
+        value: Type.String(),
+      });
+
+      const zodSchema = createZodCompatibleSchema(typeboxSchema);
+
+      // Zod v4 Mini schemas have _zod property that MCP SDK checks
+      expect((zodSchema as any)._zod).toBeDefined();
+    });
+  });
 });
diff --git a/src/agents/claude-agent-sdk/tool-bridge.ts b/src/agents/claude-agent-sdk/tool-bridge.ts
index 611f1d60d..b57deba59 100644
--- a/src/agents/claude-agent-sdk/tool-bridge.ts
+++ b/src/agents/claude-agent-sdk/tool-bridge.ts
@@ -20,6 +20,7 @@
 import type { AgentToolResult } from "@mariozechner/pi-agent-core";
 import type { TSchema } from "@sinclair/typebox";
 import { Value } from "@sinclair/typebox/value";
+import * as z from "zod/v4-mini";
 
 import { createSubsystemLogger } from "../../logging/subsystem.js";
 import { normalizeToolName } from "../tool-policy.js";
@@ -36,85 +37,136 @@ import type {
 const log = createSubsystemLogger("agents/claude-agent-sdk/tool-bridge");
 
 // ---------------------------------------------------------------------------
-// Schema conversion: TypeBox → Zod-compatible schema
+// Schema conversion: TypeBox → Zod v4 Mini schema
 // ---------------------------------------------------------------------------
 
-/**
- * Interface for Zod-compatible schema that the MCP SDK expects.
- * The SDK checks for `parse` and `safeParse` methods to identify valid schemas.
- */
-export interface ZodCompatibleSchema {
-  /** Synchronous parse - throws on validation failure */
-  parse(data: unknown): unknown;
-  /** Safe synchronous parse - returns success/error result */
-  safeParse(data: unknown): { success: true; data: unknown } | { success: false; error: unknown };
-  /** Async version of safeParse (used by MCP SDK) */
-  safeParseAsync(
-    data: unknown,
-  ): Promise<{ success: true; data: unknown } | { success: false; error: unknown }>;
-  /** Mark this as a Zod-like schema instance (SDK checks for _def or _zod) */
-  _def: { typeName: string; description?: string };
-}
+// Use z.ZodMiniType as the base type for all Zod Mini schemas
+// biome-ignore lint/suspicious/noExplicitAny: Zod Mini type system is complex; any allows proper schema composition
+type ZodMiniSchema = z.ZodMiniType<any, any>;
 
 /**
- * Wrap a TypeBox schema to make it Zod-compatible for the MCP SDK.
- *
- * The MCP SDK's McpServer.tool() checks `isZodTypeLike()` which requires:
- * - `parse` method (function)
- * - `safeParse` method (function)
- *
- * This wrapper uses TypeBox's Value module to perform validation.
+ * Convert a TypeBox property schema to a Zod v4 Mini schema.
+ * This recursive converter handles common TypeBox/JSON Schema types.
  */
-export function createZodCompatibleSchema(typeboxSchema: TSchema): ZodCompatibleSchema {
-  return {
-    parse(data: unknown): unknown {
-      // Decode handles coercion (string→number, etc.) and throws on failure
-      return Value.Decode(typeboxSchema, data);
-    },
+function convertTypeBoxPropertyToZod(propSchema: TSchema): ZodMiniSchema {
+  const type = (propSchema as { type?: string }).type;
 
-    safeParse(
-      data: unknown,
-    ): { success: true; data: unknown } | { success: false; error: unknown } {
-      try {
-        // First check if valid
-        if (!Value.Check(typeboxSchema, data)) {
-          // Get the first validation error for a useful message
-          const errors = [...Value.Errors(typeboxSchema, data)];
-          const firstError = errors[0];
-          return {
-            success: false,
-            error: {
-              message: firstError?.message ?? "Validation failed",
-              path: firstError?.path ?? "",
-              issues: errors.map((e) => ({ message: e.message, path: e.path })),
-            },
-          };
-        }
-        // Decode to apply any transformations
-        const decoded = Value.Decode(typeboxSchema, data);
-        return { success: true, data: decoded };
-      } catch (err) {
-        return {
-          success: false,
-          error: err instanceof Error ? { message: err.message } : { message: String(err) },
-        };
+  // Handle based on JSON Schema type
+  switch (type) {
+    case "string": {
+      return z.string();
+    }
+    case "number":
+    case "integer": {
+      return z.number();
+    }
+    case "boolean": {
+      return z.boolean();
+    }
+    case "array": {
+      const items = (propSchema as { items?: TSchema }).items;
+      const itemSchema = items ? convertTypeBoxPropertyToZod(items) : z.unknown();
+      return z.array(itemSchema);
+    }
+    case "object": {
+      // Nested object - recursively convert
+      const nestedProps = (propSchema as { properties?: Record<string, TSchema> }).properties;
+      const nestedRequired = (propSchema as { required?: string[] }).required ?? [];
+      if (nestedProps) {
+        const shape = buildZodShapeFromTypeBox(nestedProps, nestedRequired);
+        return z.object(shape);
+      }
+      // Object without defined properties - use passthrough
+      return z.record(z.string(), z.unknown());
+    }
+    case "null": {
+      return z.null();
+    }
+    default: {
+      // Check for enum/const
+      const enumValues = (propSchema as { enum?: string[] }).enum;
+      if (enumValues && Array.isArray(enumValues)) {
+        // Create a union of literals for enum
+        if (enumValues.length === 1) {
+          return z.literal(enumValues[0]);
+        }
+        const literals = enumValues.map((v) => z.literal(v));
+        // TypeScript requires explicit tuple type assertion for z.union
+        return z.union(literals as unknown as [ZodMiniSchema, ZodMiniSchema, ...ZodMiniSchema[]]);
       }
-    },
 
-    async safeParseAsync(
-      data: unknown,
-    ): Promise<{ success: true; data: unknown } | { success: false; error: unknown }> {
-      return this.safeParse(data);
-    },
+      const constValue = (propSchema as { const?: unknown }).const;
+      if (constValue !== undefined) {
+        return z.literal(constValue as string | number | boolean);
+      }
 
-    // Mimic Zod v3's internal structure so isZodSchemaInstance returns true
-    _def: {
-      typeName: "ZodObject",
-      description: (typeboxSchema as { description?: string }).description,
-    },
-  };
+      // Fallback to unknown for unrecognized types
+      return z.unknown();
+    }
+  }
 }
 
+/**
+ * Build a Zod shape object from TypeBox properties.
+ */
+function buildZodShapeFromTypeBox(
+  properties: Record<string, TSchema>,
+  requiredProps: string[],
+): Record<string, ZodMiniSchema> {
+  const requiredSet = new Set(requiredProps);
+  const shape: Record<string, ZodMiniSchema> = {};
+
+  for (const [propName, propSchema] of Object.entries(properties)) {
+    let zodProp = convertTypeBoxPropertyToZod(propSchema);
+
+    // Wrap in optional if not required
+    if (!requiredSet.has(propName)) {
+      zodProp = z.optional(zodProp);
+    }
+
+    shape[propName] = zodProp;
+  }
+
+  return shape;
+}
+
+/**
+ * Convert a TypeBox object schema to a Zod v4 Mini object schema.
+ *
+ * The MCP SDK natively supports Zod v4 Mini schemas. By converting TypeBox
+ * to real Zod schemas, we get proper JSON Schema generation for Claude
+ * and validation that matches what the SDK expects.
+ */
+export function convertTypeBoxToZod(typeboxSchema: TSchema): ZodMiniSchema {
+  const properties = (typeboxSchema as { properties?: Record<string, TSchema> }).properties;
+  const requiredProps = (typeboxSchema as { required?: string[] }).required ?? [];
+
+  if (!properties || typeof properties !== "object") {
+    // No properties defined - return a permissive object schema
+    return z.object({});
+  }
+
+  const shape = buildZodShapeFromTypeBox(properties, requiredProps);
+  return z.object(shape);
+}
+
+/**
+ * Create a Zod v4 Mini schema from a tool's TypeBox parameters.
+ * Returns undefined if the tool has no parameters.
+ */
+export function extractZodSchema(tool: AnyAgentTool): ZodMiniSchema | undefined {
+  const schema = tool.parameters as TSchema | undefined;
+  if (!schema || typeof schema !== "object") {
+    return undefined;
+  }
+  return convertTypeBoxToZod(schema);
+}
+
+// Legacy exports for backward compatibility
+export type ZodCompatibleSchema = ZodMiniSchema;
+export const createZodCompatibleSchema = convertTypeBoxToZod;
+export const extractZodCompatibleSchema = extractZodSchema;
+
 /**
  * Extract a clean JSON Schema object from a TypeBox schema.
  *
@@ -136,20 +188,6 @@ export function extractJsonSchema(tool: AnyAgentTool): Record<string, unknown> {
   }
 }
 
-/**
- * Create a Zod-compatible schema from a tool's TypeBox parameters.
- * Falls back to a permissive schema if the tool has no parameters.
- */
-export function extractZodCompatibleSchema(tool: AnyAgentTool): ZodCompatibleSchema | undefined {
-  const schema = tool.parameters as TSchema | undefined;
-  if (!schema || typeof schema !== "object") {
-    // Return undefined to indicate no input schema
-    // The MCP SDK will then call handler(extra) instead of handler(args, extra)
-    return undefined;
-  }
-  return createZodCompatibleSchema(schema);
-}
-
 // ---------------------------------------------------------------------------
 // Result conversion: AgentToolResult → McpCallToolResult
 // ---------------------------------------------------------------------------