fix(skills): load Linux-tagged skills on Termux (android sys.platform)

Reported by @LikiusInik in Discord: on Termux only 3 built-in skills
appeared and /gh-pr-workflow + every other slash-skill from
github/productivity/mlops was missing.

Root cause: skill_matches_platform() compares sys.platform.startswith()
against the skill's platforms list. Termux is a Linux userland on
Android, but Python 3.13+ reports sys.platform == "android" instead of
"linux" — so the ~60 built-in skills tagged platforms:[linux,macos,
windows] (github-pr-workflow, google-workspace, github-auth,
huggingface-hub, etc.) all got filtered out at the listing step in
tools/skills_tool.py:_find_all_skills and never appeared as /slash
commands or in skill_view.

Fix: when is_termux() detects we're running inside Termux, accept
"linux" platform tags regardless of whether sys.platform is "linux"
(pre-3.13) or "android" (3.13+). Also accept explicit
platforms:[termux] / [android] tags. macOS-only and Windows-only
skills correctly remain excluded.

E2E (simulated TERMUX_VERSION=set + sys.platform="android"):
  Before: _find_all_skills() returned ~3 skills.
  After:  _find_all_skills() returns 84 skills including
          github-pr-workflow, google-workspace, github-auth,
          huggingface-hub. Apple-only skills remain excluded.

Non-Termux Linux/macOS/Windows behavior unchanged (verified).

Tests: tests/agent/test_skill_utils.py — 9 new cases covering
android-as-Termux, the [linux,macos,windows] case, macOS-only
exclusion, explicit termux/android tags, non-Termux Android safety,
and unchanged behavior on real Linux/macOS.

agent/skill_utils.py

@@ -12,7 +12,7 @@ import sys
 from pathlib import Path
 from typing import Any, Dict, List, Optional, Set, Tuple
 
-from hermes_constants import get_config_path, get_skills_dir
+from hermes_constants import get_config_path, get_skills_dir, is_termux
 
 logger = logging.getLogger(__name__)
 
@@ -136,6 +136,14 @@ def skill_matches_platform(frontmatter: Dict[str, Any]) -> bool:
 
     If the field is absent or empty the skill is compatible with **all**
     platforms (backward-compatible default).
+
+    Termux note: on Termux/Android, ``sys.platform`` is ``"linux"`` on
+    older Pythons but became ``"android"`` on Python 3.13+. Termux is a
+    Linux userland riding on the Android kernel, so skills tagged
+    ``linux`` are treated as compatible in Termux regardless of which
+    ``sys.platform`` value Python reports. Individual Linux commands
+    inside a skill may still misbehave (no systemd, BusyBox utils, no
+    apt/dnf, etc.) but that is on the skill, not on platform gating.
     """
     platforms = frontmatter.get("platforms")
     if not platforms:
@@ -143,11 +151,21 @@ def skill_matches_platform(frontmatter: Dict[str, Any]) -> bool:
     if not isinstance(platforms, list):
         platforms = [platforms]
     current = sys.platform
+    running_in_termux = is_termux()
     for platform in platforms:
         normalized = str(platform).lower().strip()
         mapped = PLATFORM_MAP.get(normalized, normalized)
         if current.startswith(mapped):
             return True
+        # Termux runs a Linux userland on Android. Accept linux-tagged
+        # skills regardless of whether sys.platform is "linux" (pre-3.13
+        # Termux) or "android" (Python 3.13+ Termux, and any other
+        # Android runtime).
+        if running_in_termux and mapped == "linux":
+            return True
+        # Explicit termux/android tags match a Termux session too.
+        if running_in_termux and mapped in ("termux", "android"):
+            return True
     return False
 
 

tests/agent/test_skill_utils.py

@@ -1,6 +1,12 @@
 """Tests for agent/skill_utils.py."""
 
-from agent.skill_utils import extract_skill_conditions, iter_skill_index_files
+from unittest.mock import patch
+
+from agent.skill_utils import (
+    extract_skill_conditions,
+    iter_skill_index_files,
+    skill_matches_platform,
+)
 
 
 def test_metadata_as_dict_with_hermes():
@@ -94,3 +100,100 @@ def test_iter_skill_index_files_prunes_dependency_dirs(tmp_path):
     found = list(iter_skill_index_files(tmp_path, "SKILL.md"))
 
     assert found == [real / "SKILL.md"]
+
+
+# ── skill_matches_platform on Termux ──────────────────────────────────────
+
+
+class TestSkillMatchesPlatformTermux:
+    """Termux is Linux userland on Android. Skills tagged platforms:[linux]
+    must load there regardless of whether Python reports sys.platform as
+    "linux" (pre-3.13) or "android" (3.13+). Reported by user @LikiusInik
+    in May 2026 — only 3 built-in skills appeared on Termux because every
+    github/productivity/mlops skill is tagged platforms:[linux,macos,windows]
+    and sys.platform=="android" did not start with "linux".
+    """
+
+    def test_no_platforms_field_matches_everywhere(self):
+        # Backward-compat default — skills without a platforms tag load
+        # on any OS, Termux included.
+        with patch("agent.skill_utils.sys.platform", "android"), patch(
+            "agent.skill_utils.is_termux", return_value=True
+        ):
+            assert skill_matches_platform({}) is True
+            assert skill_matches_platform({"name": "foo"}) is True
+
+    def test_linux_skill_loads_on_termux_android_platform(self):
+        # Python 3.13+ on Termux reports sys.platform == "android".
+        fm = {"platforms": ["linux"]}
+        with patch("agent.skill_utils.sys.platform", "android"), patch(
+            "agent.skill_utils.is_termux", return_value=True
+        ):
+            assert skill_matches_platform(fm) is True
+
+    def test_linux_macos_windows_skill_loads_on_termux(self):
+        # The common "[linux, macos, windows]" tag used by github-*,
+        # productivity, mlops, etc.
+        fm = {"platforms": ["linux", "macos", "windows"]}
+        with patch("agent.skill_utils.sys.platform", "android"), patch(
+            "agent.skill_utils.is_termux", return_value=True
+        ):
+            assert skill_matches_platform(fm) is True
+
+    def test_linux_skill_loads_on_termux_linux_platform(self):
+        # Pre-3.13 Termux reports sys.platform == "linux" already — this
+        # works without the Termux escape hatch but must still pass.
+        fm = {"platforms": ["linux"]}
+        with patch("agent.skill_utils.sys.platform", "linux"), patch(
+            "agent.skill_utils.is_termux", return_value=True
+        ):
+            assert skill_matches_platform(fm) is True
+
+    def test_macos_only_skill_still_excluded_on_termux(self):
+        # macOS-only skills (apple-notes, imessage, ...) should NOT load
+        # on Termux. The Termux fallback only widens platforms:[linux,...].
+        fm = {"platforms": ["macos"]}
+        with patch("agent.skill_utils.sys.platform", "android"), patch(
+            "agent.skill_utils.is_termux", return_value=True
+        ):
+            assert skill_matches_platform(fm) is False
+
+    def test_windows_only_skill_still_excluded_on_termux(self):
+        fm = {"platforms": ["windows"]}
+        with patch("agent.skill_utils.sys.platform", "android"), patch(
+            "agent.skill_utils.is_termux", return_value=True
+        ):
+            assert skill_matches_platform(fm) is False
+
+    def test_explicit_termux_or_android_tag_matches(self):
+        # Skills can also opt in explicitly via platforms:[termux] or
+        # platforms:[android] — both should match a Termux session.
+        with patch("agent.skill_utils.sys.platform", "android"), patch(
+            "agent.skill_utils.is_termux", return_value=True
+        ):
+            assert skill_matches_platform({"platforms": ["termux"]}) is True
+            assert skill_matches_platform({"platforms": ["android"]}) is True
+
+    def test_non_termux_android_does_not_widen(self):
+        # If we're somehow on a plain Android Python (not Termux), don't
+        # silently load Linux skills — Termux is the supported environment.
+        fm = {"platforms": ["linux"]}
+        with patch("agent.skill_utils.sys.platform", "android"), patch(
+            "agent.skill_utils.is_termux", return_value=False
+        ):
+            assert skill_matches_platform(fm) is False
+
+    def test_linux_skill_on_real_linux_unaffected(self):
+        # The non-Termux Linux path must not change.
+        fm = {"platforms": ["linux"]}
+        with patch("agent.skill_utils.sys.platform", "linux"), patch(
+            "agent.skill_utils.is_termux", return_value=False
+        ):
+            assert skill_matches_platform(fm) is True
+
+    def test_macos_skill_on_real_macos_unaffected(self):
+        fm = {"platforms": ["macos"]}
+        with patch("agent.skill_utils.sys.platform", "darwin"), patch(
+            "agent.skill_utils.is_termux", return_value=False
+        ):
+            assert skill_matches_platform(fm) is True