diff --git a/src/__tests__/server.assertions.test.ts b/src/__tests__/server.assertions.test.ts
new file mode 100644
index 0000000..623b213
--- /dev/null
+++ b/src/__tests__/server.assertions.test.ts
@@ -0,0 +1,226 @@
+import {
+  assertInput,
+  assertInputString,
+  assertInputStringLength,
+  assertInputStringArrayEntryLength,
+  assertInputStringNumberEnumLike
+} from '../server.assertions';
+
+describe('assertInput', () => {
+  it.each([
+    {
+      description: 'basic string validation',
+      param: '',
+      condition: (value: any) => typeof value === 'string' && value.trim().length > 0
+    },
+    {
+      description: 'pattern in string validation',
+      param: 'patternfly://lorem-ipsum',
+      condition: (value: any) => new RegExp('patternfly://', 'i').test(value)
+    },
+    {
+      description: 'array entry length validation',
+      param: ['lorem', 'ipsum'],
+      condition: (value: any) => Array.isArray(value) && value.length > 2
+    }
+  ])('should throw an error for validation, $description', ({ param, condition }) => {
+    const errorMessage = `Lorem ipsum error message for ${param} validation.`;
+
+    expect(() => assertInput(
+      condition,
+      errorMessage
+    )).toThrow(errorMessage);
+  });
+});
+
+describe('assertInputString', () => {
+  it.each([
+    {
+      description: 'empty string',
+      param: ''
+    },
+    {
+      description: 'undefined',
+      param: undefined
+    },
+    {
+      description: 'number',
+      param: 1
+    },
+    {
+      description: 'null',
+      param: null
+    }
+  ])('should throw an error for validation, $description', ({ param }) => {
+    const errorMessage = '"Input" must be a string';
+
+    expect(() => assertInputString(
+      param
+    )).toThrow(errorMessage);
+  });
+});
+
+describe('assertInputStringLength', () => {
+  it.each([
+    {
+      description: 'empty string',
+      param: ''
+    },
+    {
+      description: 'undefined',
+      param: undefined
+    },
+    {
+      description: 'number',
+      param: 1
+    },
+    {
+      description: 'null',
+      param: null
+    },
+    {
+      description: 'max',
+      param: 'lorem ipsum',
+      options: { max: 5 }
+    },
+    {
+      description: 'min',
+      param: 'lorem ipsum',
+      options: { min: 15 }
+    },
+    {
+      description: 'max and min',
+      param: 'lorem ipsum',
+      options: { min: 1, max: 10 }
+    },
+    {
+      description: 'max and min and display name',
+      param: 'lorem ipsum',
+      options: { min: 1, max: 10, inputDisplayName: 'lorem ipsum' }
+    },
+    {
+      description: 'max and min and description',
+      param: 'lorem ipsum',
+      options: { min: 1, max: 10, message: 'dolor sit amet, consectetur adipiscing elit.' }
+    }
+  ])('should throw an error for validation, $description', ({ param, options }) => {
+    const errorMessage = options?.message || `"${options?.inputDisplayName || 'Input'}" must be a string`;
+
+    expect(() => assertInputStringLength(
+      param,
+      { min: 1, max: 100, ...options } as any
+    )).toThrow(errorMessage);
+  });
+});
+
+describe('assertInputStringArrayEntryLength', () => {
+  it.each([
+    {
+      description: 'empty string',
+      param: ''
+    },
+    {
+      description: 'undefined',
+      param: undefined
+    },
+    {
+      description: 'number',
+      param: 1
+    },
+    {
+      description: 'null',
+      param: null
+    },
+    {
+      description: 'max',
+      param: ['lorem ipsum'],
+      options: { max: 5 }
+    },
+    {
+      description: 'min',
+      param: ['lorem ipsum'],
+      options: { min: 15 }
+    },
+    {
+      description: 'max and min',
+      param: ['lorem ipsum'],
+      options: { min: 1, max: 10 }
+    },
+    {
+      description: 'max and min and display name',
+      param: ['lorem ipsum'],
+      options: { min: 1, max: 10, inputDisplayName: 'lorem ipsum' }
+    },
+    {
+      description: 'max and min and description',
+      param: ['lorem ipsum'],
+      options: { min: 1, max: 10, message: 'dolor sit amet, consectetur adipiscing elit.' }
+    }
+  ])('should throw an error for validation, $description', ({ param, options }) => {
+    const errorMessage = options?.message || `"${options?.inputDisplayName || 'Input'}" array must contain strings`;
+
+    expect(() => assertInputStringArrayEntryLength(
+      param as any,
+      { min: 1, max: 100, ...options } as any
+    )).toThrow(errorMessage);
+  });
+});
+
+describe('assertInputStringNumberEnumLike', () => {
+  it.each([
+    {
+      description: 'empty string',
+      param: '',
+      compare: [2, 3]
+    },
+    {
+      description: 'undefined',
+      param: undefined,
+      compare: [2, 3]
+    },
+    {
+      description: 'null',
+      param: null,
+      compare: [2, 3]
+    },
+    {
+      description: 'number',
+      param: 1,
+      compare: [2, 3]
+    },
+    {
+      description: 'string',
+      param: 'lorem ipsum',
+      compare: ['amet', 'dolor sit']
+    },
+    {
+      description: 'string and display name',
+      param: 'lorem ipsum',
+      compare: ['amet', 'dolor sit'],
+      options: { inputDisplayName: 'lorem ipsum' }
+    },
+    {
+      description: 'string and description',
+      param: 'lorem ipsum',
+      compare: [1, 2],
+      options: { message: 'dolor sit amet, consectetur adipiscing elit.' }
+    }
+  ])('should throw an error for validation, $description', ({ param, compare, options }) => {
+    const errorMessage = options?.message || `"${options?.inputDisplayName || 'Input'}" must be one of the following values`;
+
+    expect(() => assertInputStringNumberEnumLike(
+      param as any,
+      compare as any,
+      { ...options } as any
+    )).toThrow(errorMessage);
+  });
+
+  it('should throw an internal error for validation when missing comparison values', () => {
+    const errorMessage = 'List of allowed values is empty';
+
+    expect(() => assertInputStringNumberEnumLike(
+      1,
+      []
+    )).toThrow(errorMessage);
+  });
+});
diff --git a/src/server.assertions.ts b/src/server.assertions.ts
new file mode 100644
index 0000000..80099d1
--- /dev/null
+++ b/src/server.assertions.ts
@@ -0,0 +1,141 @@
+import assert from 'node:assert';
+import { ErrorCode, McpError } from '@modelcontextprotocol/sdk/types.js';
+
+/**
+ * MCP assert. Centralizes and throws an error if the validation fails.
+ *
+ * @param condition - The function or condition to be validated.
+ * @param message - The error message, or function that returns the error message, to be thrown if the validation fails.
+ * @param {McpError} code - The error code to be thrown if the validation fails. Defaults to `ErrorCode.InvalidParams`.
+ *
+ * @throws {McpError} Throws the provided error message if the input validation fails.
+ */
+const mcpAssert = (condition: unknown, message: string | (() => string), code: ErrorCode = ErrorCode.InvalidParams) => {
+  try {
+    const result = typeof condition === 'function' ? condition() : condition;
+    const resultMessage = typeof message === 'function' ? message() : message;
+
+    assert.ok(result, resultMessage);
+  } catch (error) {
+    throw new McpError(code, (error as Error).message);
+  }
+};
+
+/**
+ * General purpose input assert/validation function.
+ *
+ * @alias mcpAssert
+ *
+ * @param condition - The function or condition to be validated.
+ * @param message - The error message, or function that returns the error message, to be thrown if the validation fails.
+ * @param {McpError} [code] - The error code to be thrown if the validation fails. Defaults to `ErrorCode.InvalidParams`.
+ *
+ * @throws {McpError} Throws the provided error message if the input validation fails.
+ */
+function assertInput(
+  condition: unknown,
+  message: string | (() => string),
+  code?: ErrorCode
+): asserts condition {
+  mcpAssert(condition, message, code);
+}
+
+/**
+ * Assert/validate if the input is a string.
+ *
+ * @param input - The input value
+ * @param options - Validation options
+ * @param options.inputDisplayName - Display name for the input. Used in the default error message. Defaults to 'Input'.
+ * @param options.message - Custom error message. A default error message with optional `inputDisplayName` is generated if not provided.
+ *
+ * @throws McpError If input is not a string OR is empty
+ */
+function assertInputString(
+  input: unknown,
+  { inputDisplayName, message }: { inputDisplayName?: string, message?: string } = {}
+): asserts input is string {
+  const isValid = typeof input === 'string' && input.trim().length > 0;
+
+  mcpAssert(isValid, message || `"${inputDisplayName || 'Input'}" must be a string`);
+}
+
+/**
+ * Assert/validate if input is a string and meets length requirements.
+ *
+ * @param input - The input string
+ * @param options - Validation options
+ * @param options.max - Maximum length of the string
+ * @param options.min - Minimum length of the string
+ * @param options.inputDisplayName - Display name for the input. Used in the default error message. Defaults to 'Input'.
+ * @param options.message - Error description. A default error message with optional `inputDisplayName` is generated if not provided.
+ *
+ * @throws McpError If input is not a string OR does not meet length requirements
+ */
+function assertInputStringLength(
+  input: unknown,
+  { max, min, inputDisplayName, message }: { max: number, min: number, inputDisplayName?: string, message?: string }
+): asserts input is string {
+  const isValid = typeof input === 'string' && input.length <= max && input.length >= min;
+
+  mcpAssert(isValid, message || `"${inputDisplayName || 'Input'}" must be a string from "${min}" to "${max}" characters`);
+}
+
+/**
+ * Assert/validate if input array entries are strings and have length.
+ *
+ * @param input - Array of strings
+ * @param options - Validation options
+ * @param options.max - Maximum length of each string in the array
+ * @param options.min - Minimum length of each string in the array
+ * @param options.inputDisplayName - Display name for the input. Used in the default error messages. Defaults to 'Input'.
+ * @param options.message - Error description. A default error message with optional `inputDisplayName` is generated if not provided.
+ *
+ * @throws McpError If input is not an array of strings OR does not meet length requirements
+ */
+function assertInputStringArrayEntryLength(
+  input: unknown[],
+  { max, min, inputDisplayName, message }: { max: number, min: number, inputDisplayName?: string, message?: string }
+): asserts input is string[] {
+  const isValid = Array.isArray(input) && input.every(entry => typeof entry === 'string' && entry.length <= max && entry.length >= min);
+
+  mcpAssert(isValid, message || `"${inputDisplayName || 'Input'}" array must contain strings from "${min}" to "${max}" characters`);
+}
+
+/**
+ * Assert/validate if input is a string or number AND is one of the allowed values.
+ *
+ * @param input - The input value
+ * @param values - List of allowed values
+ * @param options - Validation options
+ * @param options.inputDisplayName - Display name for the input. Used in the default error messages. Defaults to 'Input'.
+ * @param options.message - Error description. A default error message with optional `inputDisplayName` is generated if not provided.
+ *
+ * @throws McpError If input is not a string or number OR is not one of the allowed values
+ */
+function assertInputStringNumberEnumLike(
+  input: unknown,
+  values: unknown[],
+  { inputDisplayName, message }: { inputDisplayName?: string, message?: string } = {}
+): asserts input is unknown[] {
+  const hasArrayWithLength = Array.isArray(values) && values.length;
+  let updatedDescription = message || `"${inputDisplayName || 'Input'}" must be one of the following values: ${values.join(', ')}`;
+  let errorCode = ErrorCode.InvalidParams;
+
+  if (!hasArrayWithLength) {
+    errorCode = ErrorCode.InternalError;
+    updatedDescription = `Unable to confirm "${inputDisplayName || 'input'}." List of allowed values is empty or undefined.`;
+  }
+
+  const isStringOrNumber = (typeof input === 'string' && typeof input.trim().length) || typeof input === 'number';
+  const isValid = isStringOrNumber && hasArrayWithLength && values.includes(input);
+
+  mcpAssert(isValid, updatedDescription, errorCode);
+}
+
+export {
+  assertInput,
+  assertInputString,
+  assertInputStringLength,
+  assertInputStringArrayEntryLength,
+  assertInputStringNumberEnumLike
+};