diff --git a/get-shit-done/bin/lib/core.cjs b/get-shit-done/bin/lib/core.cjs
index f3809e9d4..1d151753a 100644
--- a/get-shit-done/bin/lib/core.cjs
+++ b/get-shit-done/bin/lib/core.cjs
@@ -465,6 +465,7 @@ function loadConfig(cwd, options = {}) {
       firecrawl: get('firecrawl') ?? defaults.firecrawl,
       exa_search: get('exa_search') ?? defaults.exa_search,
       tdd_mode: get('tdd_mode', { section: 'workflow', field: 'tdd_mode' }) ?? false,
+      mvp_mode: get('mvp_mode', { section: 'workflow', field: 'mvp_mode' }) ?? false,
       text_mode: get('text_mode', { section: 'workflow', field: 'text_mode' }) ?? defaults.text_mode,
       auto_advance: get('auto_advance', { section: 'workflow', field: 'auto_advance' }) ?? false,
       _auto_chain_active: get('_auto_chain_active', { section: 'workflow', field: '_auto_chain_active' }) ?? false,
diff --git a/get-shit-done/bin/lib/phase-command-router.cjs b/get-shit-done/bin/lib/phase-command-router.cjs
index 14a6eeaad..c3db5f14b 100644
--- a/get-shit-done/bin/lib/phase-command-router.cjs
+++ b/get-shit-done/bin/lib/phase-command-router.cjs
@@ -15,6 +15,7 @@ function routePhaseCommand({ phase, args, cwd, raw, error }) {
     error,
     unknownMessage: (_subcommand, available) => `Unknown phase subcommand. Available: ${available.join(', ')}`,
     handlers: {
+      'mvp-mode': () => phase.cmdPhaseMvpMode(cwd, args.slice(2), raw),
       'next-decimal': () => phase.cmdPhaseNextDecimal(cwd, args[2], raw),
       add: () => {
         let customId = null;
diff --git a/get-shit-done/bin/lib/phase.cjs b/get-shit-done/bin/lib/phase.cjs
index 400aa6dcf..e8170f32b 100644
--- a/get-shit-done/bin/lib/phase.cjs
+++ b/get-shit-done/bin/lib/phase.cjs
@@ -4,7 +4,7 @@
 
 const fs = require('fs');
 const path = require('path');
-const { escapeRegex, loadConfig, normalizePhaseName, phaseMarkdownRegexSource, comparePhaseNum, findPhaseInternal, getArchivedPhaseDirs, generateSlugInternal, getMilestonePhaseFilter, stripShippedMilestones, extractCurrentMilestone, replaceInCurrentMilestone, toPosixPath, output, error, readSubdirectories, phaseTokenMatches } = require('./core.cjs');
+const { escapeRegex, loadConfig, normalizePhaseName, phaseMarkdownRegexSource, comparePhaseNum, findPhaseInternal, getArchivedPhaseDirs, generateSlugInternal, getMilestonePhaseFilter, stripShippedMilestones, extractCurrentMilestone, replaceInCurrentMilestone, toPosixPath, output, error, readSubdirectories, phaseTokenMatches, ERROR_REASON } = require('./core.cjs');
 const { platformWriteSync, platformReadSync, platformEnsureDir } = require('./shell-command-projection.cjs');
 const { planningDir, withPlanningLock } = require('./planning-workspace.cjs');
 const { extractFrontmatter } = require('./frontmatter.cjs');
@@ -210,6 +210,65 @@ function cmdPhaseNextDecimal(cwd, basePhase, raw) {
   }
 }
 
+function getRoadmapModeForPhase(cwd, phaseNum) {
+  const roadmapPath = path.join(planningDir(cwd), 'ROADMAP.md');
+  if (!fs.existsSync(roadmapPath)) return null;
+
+  const rawContent = fs.readFileSync(roadmapPath, 'utf-8');
+  const milestoneContent = extractCurrentMilestone(rawContent, cwd);
+  const fullContent = stripShippedMilestones(rawContent);
+  const escapedPhase = phaseMarkdownRegexSource(phaseNum);
+  const phaseHeader = new RegExp(`#{2,4}\\s*Phase\\s+${escapedPhase}\\s*:`, 'i');
+
+  for (const content of [milestoneContent, fullContent]) {
+    const headerMatch = content.match(phaseHeader);
+    if (!headerMatch || headerMatch.index === undefined) continue;
+
+    const sectionStart = headerMatch.index;
+    const rest = content.slice(sectionStart);
+    const nextHeader = rest.slice(headerMatch[0].length).match(/\n#{2,4}\s+Phase\s+\d/i);
+    const sectionEnd = nextHeader ? sectionStart + headerMatch[0].length + nextHeader.index : content.length;
+    const section = content.slice(sectionStart, sectionEnd);
+    const modeMatch = section.match(/\*\*Mode(?::\*\*|\*\*:)\s*([^\n]+)/i);
+    if (modeMatch) return modeMatch[1].trim().toLowerCase();
+  }
+
+  return null;
+}
+
+function cmdPhaseMvpMode(cwd, args, raw) {
+  const phaseNum = args[0];
+  if (!phaseNum) {
+    error('Usage: phase.mvp-mode <phase-number> [--cli-flag]', ERROR_REASON.USAGE);
+  }
+
+  const cliFlagPresent = args.includes('--cli-flag');
+  const roadmapMode = getRoadmapModeForPhase(cwd, phaseNum);
+  const config = loadConfig(cwd);
+  const configMvpMode = Boolean(config.mvp_mode);
+
+  let active = false;
+  let source = 'none';
+  if (cliFlagPresent) {
+    active = true;
+    source = 'cli_flag';
+  } else if (roadmapMode === 'mvp') {
+    active = true;
+    source = 'roadmap';
+  } else if (configMvpMode) {
+    active = true;
+    source = 'config';
+  }
+
+  output({
+    active,
+    source,
+    roadmap_mode: roadmapMode,
+    config_mvp_mode: configMvpMode,
+    cli_flag_present: cliFlagPresent,
+  }, raw);
+}
+
 function cmdFindPhase(cwd, phase, raw) {
   if (!phase) {
     error('phase identifier required');
@@ -1329,6 +1388,7 @@ module.exports = {
   cmdPhasePlanIndex,
   cmdPhaseAdd,
   cmdPhaseAddBatch,
+  cmdPhaseMvpMode,
   cmdPhaseInsert,
   cmdPhaseRemove,
   cmdPhaseComplete,
diff --git a/tests/feat-3251-command-aliases-manifest-coverage.test.cjs b/tests/feat-3251-command-aliases-manifest-coverage.test.cjs
index 0cdb14b36..9904b2080 100644
--- a/tests/feat-3251-command-aliases-manifest-coverage.test.cjs
+++ b/tests/feat-3251-command-aliases-manifest-coverage.test.cjs
@@ -10,7 +10,10 @@
 
 const { describe, test } = require('node:test');
 const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const os = require('node:os');
 const path = require('path');
+const { spawnSync } = require('node:child_process');
 
 const REPO_ROOT = path.join(__dirname, '..');
 const COMMAND_ALIASES_FILE = path.join(
@@ -20,6 +23,7 @@ const COMMAND_ALIASES_FILE = path.join(
   'lib',
   'command-aliases.generated.cjs',
 );
+const GSD_TOOLS = path.join(REPO_ROOT, 'get-shit-done', 'bin', 'gsd-tools.cjs');
 
 const MISSING_14 = [
   'check.decision-coverage-plan',
@@ -126,3 +130,105 @@ describe('feat-3251: command-aliases.generated.cjs manifest coverage', () => {
     );
   });
 });
+
+function createProject() {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-3251-dispatch-'));
+  fs.mkdirSync(path.join(dir, '.planning', 'phases'), { recursive: true });
+  return dir;
+}
+
+function runGsdTools(args, cwd) {
+  return spawnSync(process.execPath, [GSD_TOOLS, ...args], {
+    cwd,
+    encoding: 'utf8',
+  });
+}
+
+function listProjectFiles(projectDir) {
+  const files = [];
+  function walk(dir) {
+    if (!fs.existsSync(dir)) return;
+    for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
+      const full = path.join(dir, entry.name);
+      const rel = path.relative(projectDir, full);
+      if (entry.isDirectory()) walk(full);
+      else files.push(rel);
+    }
+  }
+  walk(projectDir);
+  return files.sort();
+}
+
+describe('feat-3251: generated aliases dispatch through real gsd-tools behavior', () => {
+  test('phase.mvp-mode spaced alias resolves CLI flag precedence', () => {
+    const projectDir = createProject();
+    try {
+      const result = runGsdTools(['phase', 'mvp-mode', '1', '--cli-flag'], projectDir);
+      assert.equal(result.status, 0, result.stderr);
+
+      const output = JSON.parse(result.stdout);
+      assert.deepEqual(output, {
+        active: true,
+        source: 'cli_flag',
+        roadmap_mode: null,
+        config_mvp_mode: false,
+        cli_flag_present: true,
+      });
+    } finally {
+      fs.rmSync(projectDir, { recursive: true, force: true });
+    }
+  });
+
+  test('phase.mvp-mode spaced alias resolves ROADMAP mode without mutating files', () => {
+    const projectDir = createProject();
+    try {
+      fs.writeFileSync(
+        path.join(projectDir, '.planning', 'ROADMAP.md'),
+        [
+          '# Roadmap',
+          '',
+          '## v1.0.0',
+          '',
+          '### Phase 1: User Auth',
+          '**Goal:** Users can sign in.',
+          '**Mode:** mvp',
+          '',
+        ].join('\n'),
+      );
+      const beforeFiles = listProjectFiles(projectDir);
+
+      const result = runGsdTools(['phase', 'mvp-mode', '1'], projectDir);
+      assert.equal(result.status, 0, result.stderr);
+
+      const output = JSON.parse(result.stdout);
+      assert.equal(output.active, true);
+      assert.equal(output.source, 'roadmap');
+      assert.equal(output.roadmap_mode, 'mvp');
+      assert.equal(output.config_mvp_mode, false);
+      assert.equal(output.cli_flag_present, false);
+      assert.deepEqual(listProjectFiles(projectDir), beforeFiles);
+    } finally {
+      fs.rmSync(projectDir, { recursive: true, force: true });
+    }
+  });
+
+  test('phase.mvp-mode JSON error is typed and leaves project files untouched', () => {
+    const projectDir = createProject();
+    try {
+      const beforeFiles = listProjectFiles(projectDir);
+      const result = runGsdTools(['--json-errors', 'phase', 'mvp-mode'], projectDir);
+      assert.notEqual(result.status, 0);
+      assert.equal(result.stdout, '');
+
+      const error = JSON.parse(result.stderr);
+      assert.deepEqual(Object.keys(error).sort(), ['message', 'ok', 'reason']);
+      assert.equal(error.ok, false);
+      assert.equal(error.reason, 'usage');
+      assert.equal(typeof error.message, 'string');
+      assert.equal(/\n\s*at\s/.test(result.stderr), false, 'non-debug failure must not print a stack trace');
+      assert.deepEqual(listProjectFiles(projectDir), beforeFiles);
+    } finally {
+      fs.rmSync(projectDir, { recursive: true, force: true });
+    }
+  });
+});