diff --git a/changelog.d/tsk-aa5qck-agent-avatars-module.md b/changelog.d/tsk-aa5qck-agent-avatars-module.md
new file mode 100644
index 000000000..997c20826
--- /dev/null
+++ b/changelog.d/tsk-aa5qck-agent-avatars-module.md
@@ -0,0 +1,3 @@
+### Changed
+
+- Extracted avatar slug and avatar directory logic from `tinyagentos/routes/auth.py` into a new `tinyagentos/agent_avatars.py` module, and added `avatar_source_path` and `avatar_hash` helpers.
diff --git a/tests/test_agent_avatars.py b/tests/test_agent_avatars.py
new file mode 100644
index 000000000..00fa37936
--- /dev/null
+++ b/tests/test_agent_avatars.py
@@ -0,0 +1,45 @@
+"""Tests for tinyagentos.agent_avatars module (avatar_source_path + avatar_hash)."""
+from __future__ import annotations
+
+import hashlib
+from pathlib import Path
+
+import pytest
+
+from tinyagentos import agent_avatars as aa
+from tinyagentos.agent_avatars import avatar_hash, avatar_source_path
+from tinyagentos.routes.auth import _avatar_slug
+
+
+class TestAvatarSourcePathAndHash:
+
+    def test_no_jpg_returns_none(self, tmp_path, monkeypatch):
+        monkeypatch.setattr(aa, "LOCK_AVATAR_DIR", str(tmp_path))
+        assert avatar_source_path("Some Agent") is None
+        assert avatar_hash("Some Agent") is None
+
+    def test_existing_jpg_returns_path_and_hash(self, tmp_path, monkeypatch):
+        monkeypatch.setattr(aa, "LOCK_AVATAR_DIR", str(tmp_path))
+        name = "Some Agent"
+        slug = _avatar_slug(name)
+        (tmp_path / f"{slug}.jpg").write_bytes(b"one")
+        assert avatar_source_path(name) == tmp_path / f"{slug}.jpg"
+        h = avatar_hash(name)
+        assert isinstance(h, str)
+        assert len(h) == 16
+        assert h == hashlib.sha256(b"one").hexdigest()[:16]
+
+    def test_hash_changes_when_file_changes(self, tmp_path, monkeypatch):
+        monkeypatch.setattr(aa, "LOCK_AVATAR_DIR", str(tmp_path))
+        name = "Some Agent"
+        slug = _avatar_slug(name)
+        p = tmp_path / f"{slug}.jpg"
+        p.write_bytes(b"one")
+        first = avatar_hash(name)
+        p.write_bytes(b"two")
+        second = avatar_hash(name)
+        assert first != second
+
+    def test_imported_slug_matches_module_slug(self):
+        name = "Some Agent"
+        assert _avatar_slug(name) == aa._avatar_slug(name)
diff --git a/tinyagentos/agent_avatars.py b/tinyagentos/agent_avatars.py
new file mode 100644
index 000000000..f8ad5182b
--- /dev/null
+++ b/tinyagentos/agent_avatars.py
@@ -0,0 +1,38 @@
+from __future__ import annotations
+
+import hashlib
+import os
+from pathlib import Path
+
+LOCK_AVATAR_DIR = os.environ.get("TAOS_LOCK_AVATAR_DIR", "/var/lib/taos/lock-avatars")
+
+
+def _avatar_slug(name: str) -> str:
+    """Slug for an agent name, restricted to characters that cannot traverse.
+
+    Anything outside [a-z0-9-] is dropped rather than escaped: this value is
+    used to build a filesystem path, so a conservative whitelist is the control
+    that keeps "../" and absolute paths out, not a sanitiser that tries to spot
+    bad input.
+    """
+    out = []
+    for ch in name.strip().lower():
+        if ch.isalnum() and ch.isascii():
+            out.append(ch)
+        elif out and out[-1] != "-":
+            out.append("-")
+    return "".join(out).strip("-")
+
+
+def avatar_source_path(name: str) -> Path | None:
+    """Path to the avatar image file for *name*, or None if it is not installed."""
+    path = Path(LOCK_AVATAR_DIR) / f"{_avatar_slug(name)}.jpg"
+    return path if path.is_file() else None
+
+
+def avatar_hash(name: str) -> str | None:
+    """SHA-256 hex of the avatar image bytes, first 16 chars, or None."""
+    path = avatar_source_path(name)
+    if path is None:
+        return None
+    return hashlib.sha256(path.read_bytes()).hexdigest()[:16]
diff --git a/tinyagentos/routes/auth.py b/tinyagentos/routes/auth.py
index 4d3720908..7182d3e37 100644
--- a/tinyagentos/routes/auth.py
+++ b/tinyagentos/routes/auth.py
@@ -27,6 +27,7 @@
     Response,
     StreamingResponse,
 )
+from tinyagentos.agent_avatars import LOCK_AVATAR_DIR, _avatar_slug
 from tinyagentos.auth import (
     PIN_MAX_LEN,
     PIN_MIN_LEN,
@@ -9603,30 +9604,6 @@ def _attach(agent: dict) -> None:
 
 
 
-#: Where lock-screen agent avatars are read from. One flat directory of
-#: "<slug>.jpg" files, slug being the agent name lowercased with non-alphanumerics
-#: collapsed to "-". Overridable so a packaged install can point it at its own
-#: data dir rather than this default.
-LOCK_AVATAR_DIR = os.environ.get("TAOS_LOCK_AVATAR_DIR", "/var/lib/taos/lock-avatars")
-
-
-def _avatar_slug(name: str) -> str:
-    """Slug for an agent name, restricted to characters that cannot traverse.
-
-    Anything outside [a-z0-9-] is dropped rather than escaped: this value is
-    used to build a filesystem path, so a conservative whitelist is the control
-    that keeps "../" and absolute paths out, not a sanitiser that tries to spot
-    bad input.
-    """
-    out = []
-    for ch in name.strip().lower():
-        if ch.isalnum() and ch.isascii():
-            out.append(ch)
-        elif out and out[-1] != "-":
-            out.append("-")
-    return "".join(out).strip("-")
-
-
 @router.get("/lock-avatar/{slug}")
 async def lock_avatar(slug: str, request: Request):
     """Serve one lock-screen avatar. Console-only, same reasoning as the widgets.