diff --git a/get-shit-done/bin/lib/profile-output.cjs b/get-shit-done/bin/lib/profile-output.cjs
index d6918c5d0..52ca088fe 100644
--- a/get-shit-done/bin/lib/profile-output.cjs
+++ b/get-shit-done/bin/lib/profile-output.cjs
@@ -16,6 +16,7 @@ const { output, error, loadConfig } = require('./core.cjs');
 const { platformReadSync: safeReadFile, platformWriteSync, platformEnsureDir } = require('./shell-command-projection.cjs');
 const { getGlobalSkillDir } = require('./runtime-homes.cjs');
 const { formatGsdSlash, resolveRuntime } = require('./runtime-slash.cjs');
+const { resolveRuntimeNameFromCandidates } = require('./runtime-name-policy.cjs');
 
 // ─── Constants ────────────────────────────────────────────────────────────────
 
@@ -811,9 +812,16 @@ function cmdGenerateDevPreferences(cwd, options, raw) {
     let effectiveRuntime = 'claude';
     try {
       const config = loadConfig(cwd);
-      effectiveRuntime = process.env.GSD_RUNTIME || config.runtime || 'claude';
+      effectiveRuntime = resolveRuntimeNameFromCandidates(
+        process.env.GSD_RUNTIME,
+        config.runtime,
+        'claude'
+      ) || 'claude';
     } catch {
-      effectiveRuntime = process.env.GSD_RUNTIME || 'claude';
+      effectiveRuntime = resolveRuntimeNameFromCandidates(
+        process.env.GSD_RUNTIME,
+        'claude'
+      ) || 'claude';
     }
     const skillDir = getGlobalSkillDir(effectiveRuntime, 'gsd-dev-preferences');
     if (!skillDir) {
@@ -1003,7 +1011,10 @@ function cmdGenerateClaudeMd(cwd, options, raw) {
     // #3163: When runtime is codex, override the output target to AGENTS.md
     // regardless of claude_md_path, so Codex projects never write to CLAUDE.md.
     // GSD_RUNTIME env var takes precedence over config.runtime, mirroring detectRuntime().
-    const effectiveRuntime = process.env.GSD_RUNTIME || config.runtime || null;
+    const effectiveRuntime = resolveRuntimeNameFromCandidates(
+      process.env.GSD_RUNTIME,
+      config.runtime
+    );
     if (!options.output && effectiveRuntime === 'codex') {
       configClaudeMdPath = './AGENTS.md';
     }
diff --git a/get-shit-done/bin/lib/runtime-name-policy.cjs b/get-shit-done/bin/lib/runtime-name-policy.cjs
index a7635219b..0241f3fe8 100644
--- a/get-shit-done/bin/lib/runtime-name-policy.cjs
+++ b/get-shit-done/bin/lib/runtime-name-policy.cjs
@@ -57,6 +57,27 @@ function canonicalizeRuntimeName(value) {
   return aliasToCanonical.get(normalizeRuntimeToken(value)) || null;
 }
 
+/**
+ * Resolve runtime from a precedence list of candidate values.
+ *
+ * - First non-empty string candidate wins.
+ * - Known aliases are canonicalized (codex-cli -> codex).
+ * - Unknown values are normalized and returned (future-runtime tolerance).
+ *
+ * @param {...string} candidates
+ * @returns {string|null}
+ */
+function resolveRuntimeNameFromCandidates(...candidates) {
+  for (const candidate of candidates) {
+    if (typeof candidate !== 'string') continue;
+    const normalized = normalizeRuntimeToken(candidate);
+    if (!normalized) continue;
+    return canonicalizeRuntimeName(normalized) || normalized;
+  }
+  return null;
+}
+
 module.exports = {
   canonicalizeRuntimeName,
+  resolveRuntimeNameFromCandidates,
 };
diff --git a/get-shit-done/bin/lib/runtime-slash.cjs b/get-shit-done/bin/lib/runtime-slash.cjs
index 923972730..4da389cd1 100644
--- a/get-shit-done/bin/lib/runtime-slash.cjs
+++ b/get-shit-done/bin/lib/runtime-slash.cjs
@@ -1,6 +1,6 @@
 'use strict';
 
-const { canonicalizeRuntimeName } = require('./runtime-name-policy.cjs');
+const { canonicalizeRuntimeName, resolveRuntimeNameFromCandidates } = require('./runtime-name-policy.cjs');
 
 /**
  * runtime-slash.cjs — single source of truth for emitting GSD slash-command
@@ -69,10 +69,8 @@ function formatGsdSlash(commandName, runtime) {
  * @returns {string}
  */
 function resolveRuntime(projectDir) {
-  if (process.env.GSD_RUNTIME) {
-    const rawRuntime = String(process.env.GSD_RUNTIME).toLowerCase();
-    return canonicalizeRuntimeName(rawRuntime) || rawRuntime;
-  }
+  const envRuntime = resolveRuntimeNameFromCandidates(process.env.GSD_RUNTIME);
+  if (envRuntime) return envRuntime;
   if (projectDir) {
     try {
       // Read config.json directly (not via loadConfig). loadConfig has a side
@@ -87,8 +85,8 @@ function resolveRuntime(projectDir) {
         const raw = fs.readFileSync(configPath, 'utf-8');
         const parsed = JSON.parse(raw);
         if (parsed && typeof parsed === 'object' && parsed.runtime) {
-          const rawRuntime = String(parsed.runtime).toLowerCase();
-          return canonicalizeRuntimeName(rawRuntime) || rawRuntime;
+          const configRuntime = resolveRuntimeNameFromCandidates(parsed.runtime);
+          if (configRuntime) return configRuntime;
         }
       }
     } catch {
diff --git a/tests/profile-output.test.cjs b/tests/profile-output.test.cjs
index 38238d11d..bbb26da2d 100644
--- a/tests/profile-output.test.cjs
+++ b/tests/profile-output.test.cjs
@@ -174,6 +174,16 @@ describe('generate-claude-md command', () => {
     assert.ok(content.includes('.codex/skills/'));
     assert.ok(!content.includes('get-shit-done/skills'));
   });
+
+  test('codex runtime aliases default output to AGENTS.md', () => {
+    const result = runGsdTools(
+      ['generate-claude-md', '--auto', '--raw'],
+      tmpDir,
+      { GSD_RUNTIME: 'codex-cli' }
+    );
+    assert.ok(result.success, `Failed: ${result.error}`);
+    assert.ok(fs.existsSync(path.join(tmpDir, 'AGENTS.md')), 'AGENTS.md should be generated for codex aliases');
+  });
 });
 
 // ─── generate-dev-preferences ─────────────────────────────────────────────────
@@ -238,6 +248,27 @@ describe('generate-dev-preferences command', () => {
     assert.ok(fs.existsSync(out.command_path), 'runtime-aware output should be written');
   });
 
+  test('canonicalizes codex runtime aliases for skills output path', () => {
+    const analysis = {
+      profile_version: '1.0',
+      dimensions: {
+        communication_style: { rating: 'terse-direct', confidence: 'HIGH' },
+      },
+    };
+    const analysisPath = path.join(tmpDir, 'analysis.json');
+    const codexHome = path.join(tmpDir, 'codex-home');
+    fs.writeFileSync(analysisPath, JSON.stringify(analysis));
+
+    const result = runGsdTools(
+      ['generate-dev-preferences', '--analysis', analysisPath, '--raw'],
+      tmpDir,
+      { CODEX_HOME: codexHome, GSD_RUNTIME: 'codex-app' }
+    );
+    assert.ok(result.success, `Failed: ${result.error}`);
+    const out = JSON.parse(result.output);
+    assert.strictEqual(out.command_path, path.join(codexHome, 'skills', 'gsd-dev-preferences', 'SKILL.md'));
+  });
+
   test('errors for cline unless --output is supplied', () => {
     const analysis = {
       profile_version: '1.0',