diff --git a/test/test-installation-components.js b/test/test-installation-components.js
index 6e015322a..fc1d2be62 100644
--- a/test/test-installation-components.js
+++ b/test/test-installation-components.js
@@ -3318,6 +3318,52 @@ async function runTests() {
 
   console.log('');
 
+  // ============================================================
+  // Test Suite 46: Python environment check (version parsing + classification)
+  // ============================================================
+  console.log(`${colors.yellow}Test Suite 46: python-check version parsing and classification${colors.reset}\n`);
+
+  try {
+    const { parsePythonVersion, classifyPython, detectPython } = require('../tools/installer/core/python-check');
+
+    // Version parsing
+    const v312 = parsePythonVersion('Python 3.12.1');
+    assert(v312 && v312.major === 3 && v312.minor === 12 && v312.patch === 1, 'parses "Python 3.12.1"');
+    const v311 = parsePythonVersion('Python 3.11.0\n');
+    assert(v311 && v311.raw === '3.11.0', 'parses with trailing newline');
+    const v2 = parsePythonVersion('\nPython 2.7.18');
+    assert(v2 && v2.major === 2, 'parses Python 2 output (stderr-style)');
+    const noPatch = parsePythonVersion('Python 3.13');
+    assert(noPatch && noPatch.patch === 0, 'missing patch defaults to 0');
+    assert(parsePythonVersion('') === null, 'empty output returns null');
+    assert(parsePythonVersion('command not found: python3') === null, 'non-version output returns null');
+    assert(parsePythonVersion(null) === null, 'null output returns null');
+
+    // Classification against feature requirements
+    assert(classifyPython({ major: 3, minor: 11 }) === 'full', '3.11 is full support (tomllib floor)');
+    assert(classifyPython({ major: 3, minor: 13 }) === 'full', '3.13 is full support');
+    assert(classifyPython({ major: 4, minor: 0 }) === 'full', 'hypothetical 4.0 is full support');
+    assert(classifyPython({ major: 3, minor: 10 }) === 'partial', '3.10 is partial (memlog yes, tomllib no)');
+    assert(classifyPython({ major: 3, minor: 8 }) === 'partial', '3.8 is partial (memlog floor)');
+    assert(classifyPython({ major: 3, minor: 7 }) === 'unsupported', '3.7 is unsupported');
+    assert(classifyPython({ major: 2, minor: 7 }) === 'unsupported', '2.7 is unsupported');
+    assert(classifyPython(null) === 'none', 'no python is none');
+
+    // Detection smoke test — must not throw, and if it finds a Python the
+    // result must be well-formed. (CI machines may or may not have Python.)
+    const detected = detectPython();
+    assert(
+      detected === null || (typeof detected.command === 'string' && typeof detected.version.raw === 'string'),
+      'detectPython returns null or a well-formed result',
+    );
+  } catch (error) {
+    console.log(`${colors.red}Test Suite 46 setup failed: ${error.message}${colors.reset}`);
+    console.log(error.stack);
+    failed++;
+  }
+
+  console.log('');
+
   // ============================================================
   // Summary
   // ============================================================
diff --git a/tools/installer/core/python-check.js b/tools/installer/core/python-check.js
new file mode 100644
index 000000000..66d43e125
--- /dev/null
+++ b/tools/installer/core/python-check.js
@@ -0,0 +1,169 @@
+const { spawnSync } = require('node:child_process');
+const prompts = require('../prompts');
+
+// Python 3.11 added stdlib `tomllib` (PEP 680), which the shared scripts in
+// src/scripts/ (resolve_config.py, resolve_customization.py) require to read
+// BMAD's TOML config files. memlog.py is more lenient and runs on 3.8+.
+const PYTHON_FULL_SUPPORT = { major: 3, minor: 11 };
+const PYTHON_PARTIAL_SUPPORT = { major: 3, minor: 8 };
+
+// Probe order matters: on Windows the `py` launcher is the most reliable way
+// to find Python 3 (a bare `python` is often the Microsoft Store alias that
+// exits without printing a version). On POSIX, `python3` is canonical.
+const PROBE_CANDIDATES =
+  process.platform === 'win32'
+    ? [
+        { command: 'py', args: ['-3', '--version'] },
+        { command: 'python3', args: ['--version'] },
+        { command: 'python', args: ['--version'] },
+      ]
+    : [
+        { command: 'python3', args: ['--version'] },
+        { command: 'python', args: ['--version'] },
+      ];
+
+/**
+ * Parse a `python --version` output line into version parts.
+ * Python 3 prints to stdout; Python 2 printed to stderr — callers pass both.
+ * @param {string} output - Combined stdout/stderr from `python --version`
+ * @returns {{major: number, minor: number, patch: number, raw: string}|null}
+ */
+function parsePythonVersion(output) {
+  if (!output) return null;
+  const match = output.match(/Python\s+(\d+)\.(\d+)(?:\.(\d+))?/);
+  if (!match) return null;
+  return {
+    major: Number(match[1]),
+    minor: Number(match[2]),
+    patch: Number(match[3] || 0),
+    raw: `${match[1]}.${match[2]}.${match[3] || 0}`,
+  };
+}
+
+/**
+ * Classify a detected Python version against BMAD's feature requirements.
+ * @param {{major: number, minor: number}|null} version
+ * @returns {'full'|'partial'|'unsupported'|'none'}
+ */
+function classifyPython(version) {
+  if (!version) return 'none';
+  const { major, minor } = version;
+  if (major > PYTHON_FULL_SUPPORT.major || (major === PYTHON_FULL_SUPPORT.major && minor >= PYTHON_FULL_SUPPORT.minor)) {
+    return 'full';
+  }
+  if (major === PYTHON_PARTIAL_SUPPORT.major && minor >= PYTHON_PARTIAL_SUPPORT.minor) {
+    return 'partial';
+  }
+  return 'unsupported';
+}
+
+/**
+ * Probe the local environment for a Python interpreter.
+ * Tries each candidate command and returns the first that reports a version.
+ * @returns {{command: string, version: {major: number, minor: number, patch: number, raw: string}}|null}
+ */
+function detectPython() {
+  for (const candidate of PROBE_CANDIDATES) {
+    try {
+      const result = spawnSync(candidate.command, candidate.args, {
+        encoding: 'utf8',
+        timeout: 5000,
+        windowsHide: true,
+      });
+      if (result.error) continue;
+      const version = parsePythonVersion(`${result.stdout || ''}\n${result.stderr || ''}`);
+      if (version) {
+        const display = candidate.args.length > 1 ? `${candidate.command} ${candidate.args.slice(0, -1).join(' ')}` : candidate.command;
+        return { command: display, version };
+      }
+    } catch {
+      // Candidate not runnable — try the next one.
+    }
+  }
+  return null;
+}
+
+function upgradeHints() {
+  return [
+    'How to get Python 3.11+:',
+    '  macOS:        brew install python3',
+    '  Windows:      winget install Python.Python.3.12',
+    '  Linux/WSL:    sudo apt install python3  (Ubuntu 24.04+ ships 3.12; older distros: use pyenv or deadsnakes)',
+    '  Docker:       add python3 to your image (e.g. apk add python3 / apt-get install -y python3)',
+  ].join('\n');
+}
+
+/**
+ * Check the local Python environment and warn about degraded BMAD features.
+ *
+ * Warn-don't-block: most of BMAD works without Python, so the install always
+ * may proceed — but the user must explicitly acknowledge the warning so it
+ * can't scroll past unseen. In non-interactive mode (--yes) the warning is
+ * logged and the install continues without a prompt.
+ *
+ * @param {Object} [options]
+ * @param {boolean} [options.nonInteractive=false] - Skip the ack prompt (--yes mode)
+ * @returns {Promise<{status: string, detected: Object|null}>}
+ */
+async function checkPythonEnvironment({ nonInteractive = false } = {}) {
+  const detected = detectPython();
+  const status = classifyPython(detected ? detected.version : null);
+
+  if (status === 'full') {
+    await prompts.log.success(`Python ${detected.version.raw} detected (${detected.command}) — all BMAD features supported.`);
+    return { status, detected };
+  }
+
+  if (status === 'partial') {
+    await prompts.log.warn(
+      `Python ${detected.version.raw} detected (${detected.command}) — BMAD's TOML config tools need Python 3.11+ (stdlib tomllib).\n` +
+        `Works: memlog session memory. Won't work: config/customization resolution scripts.`,
+    );
+  } else {
+    const found =
+      status === 'unsupported' ? `Python ${detected.version.raw} detected (${detected.command}) — too old.` : 'No Python found on PATH.';
+    await prompts.log.warn(
+      `${found} BMAD installs fine without it, but Python-powered features\n` +
+        `(memlog session memory, TOML config resolution) won't run until Python 3.11+ is available.`,
+    );
+  }
+  await prompts.note(upgradeHints(), 'Python 3.11+ recommended');
+
+  if (nonInteractive) {
+    await prompts.log.info('Continuing without Python 3.11+ (--yes mode). You can install Python later — no reinstall needed.');
+    return { status, detected };
+  }
+
+  const choice = await prompts.select({
+    message: 'Python 3.11+ was not found. How do you want to proceed?',
+    choices: [
+      {
+        name: 'Continue install',
+        value: 'continue',
+        hint: 'BMAD works without Python — you can add Python 3.11+ later, no reinstall needed',
+      },
+      {
+        name: 'Quit and fix Python first',
+        value: 'quit',
+        hint: 'install Python 3.11+, then re-run the installer',
+      },
+    ],
+    default: 'continue',
+  });
+
+  if (choice === 'quit') {
+    await prompts.cancel('Install Python 3.11+ (see hints above), then re-run the installer.');
+    process.exit(0);
+  }
+
+  return { status, detected };
+}
+
+module.exports = {
+  checkPythonEnvironment,
+  detectPython,
+  parsePythonVersion,
+  classifyPython,
+  PYTHON_FULL_SUPPORT,
+  PYTHON_PARTIAL_SUPPORT,
+};
diff --git a/tools/installer/ui.js b/tools/installer/ui.js
index a107fb0fc..17a712a86 100644
--- a/tools/installer/ui.js
+++ b/tools/installer/ui.js
@@ -161,6 +161,14 @@ class UI {
     const messageLoader = new MessageLoader();
     await messageLoader.displayStartMessage();
 
+    // Probe the local Python before any other prompts: several BMAD features
+    // (memlog session memory, TOML config resolution) need Python 3.11+ at
+    // runtime. Warn-don't-block, but require an explicit ack so the warning
+    // can't scroll past unseen. The installer runs in the destination
+    // environment, so probing PATH here tests the right machine.
+    const { checkPythonEnvironment } = require('./core/python-check');
+    await checkPythonEnvironment({ nonInteractive: !!options.yes });
+
     // Parse channel flags (--channel/--all-*/--next=/--pin) once. Warnings
     // are surfaced immediately so the user sees them before any git ops run.
     const channelOptions = parseChannelOptions(options);