diff --git a/compose.yaml b/compose.yaml
index 9570bd3..9fee75e 100644
--- a/compose.yaml
+++ b/compose.yaml
@@ -793,7 +793,10 @@ services:
     security_opt: ["no-new-privileges:true"]
 
   hermes:
-    image: ${HERMES_IMAGE:-nousresearch/hermes-agent@sha256:143bdb9086bb2db645346179f11091e621ef6b7f4f9e5049ae7454bfeb3a0495}
+    build:
+      context: .
+      dockerfile: platform/hermes/Dockerfile
+    image: ${HERMES_IMAGE:-mike-ai/hermes-agent:0.20.5-mcpfix1}
     container_name: mike-ai-hermes
     restart: unless-stopped
     command: [/usr/local/bin/start-hermes-managed]
diff --git a/docs/CURRENT_REFERENCE.md b/docs/CURRENT_REFERENCE.md
index dd30be8..9a5cee3 100644
--- a/docs/CURRENT_REFERENCE.md
+++ b/docs/CURRENT_REFERENCE.md
@@ -122,7 +122,9 @@ Der Router übernimmt:
 - Bei einer entfernten Hermes-Desktop-App läuft Audio bewusst über das
   Hermes-Backend (`voice.client_direct: false`), weil Router und TTS nur im
   internen Docker-Netz erreichbar sind.
-- Version: 0.20.5, offizielles Image per OCI-Digest gepinnt
+- Version: 0.20.5, lokales abgeleitetes Image
+  `mike-ai/hermes-agent:0.20.5-mcpfix1`; dessen Basis ist das offizielle
+  Hermes-Image per OCI-Digest gepinnt.
 - Die gepinnte Version trägt beim Containerstart zwei eng geprüfte lokale
   Upstream-Workarounds: API-Agenten übernehmen den live registrierten
   MCP-Katalog (Hermes-Issue 69746), und `tool_search` veröffentlicht auch
diff --git a/platform/hermes/Dockerfile b/platform/hermes/Dockerfile
new file mode 100644
index 0000000..124c7d7
--- /dev/null
+++ b/platform/hermes/Dockerfile
@@ -0,0 +1,8 @@
+FROM nousresearch/hermes-agent@sha256:143bdb9086bb2db645346179f11091e621ef6b7f4f9e5049ae7454bfeb3a0495
+
+# Hermes 0.20.5 needs two narrowly scoped upstream workarounds. Apply them
+# while the image is built as root; the managed runtime only verifies that
+# the expected patch is present and never mutates the installed application.
+COPY platform/hermes/patch-api-mcp-refresh.py /tmp/patch-api-mcp-refresh.py
+RUN python /tmp/patch-api-mcp-refresh.py \
+    && rm /tmp/patch-api-mcp-refresh.py
diff --git a/platform/hermes/start-hermes-managed.sh b/platform/hermes/start-hermes-managed.sh
index 1d4c638..8e1a752 100755
--- a/platform/hermes/start-hermes-managed.sh
+++ b/platform/hermes/start-hermes-managed.sh
@@ -68,7 +68,8 @@ grep -Eq '^[[:space:]]+base_url:[[:space:]]+["'\'']?http://router:8081/v1["'\'']
 }
 
 # Hermes 0.20.5 does not refresh the API agent from the live MCP registry.
-# Apply the narrow, version-checked workaround before starting the gateway.
+# The image build applies the narrow workaround as root. At runtime this is
+# an idempotent, fail-closed verification and must never need to write files.
 python /usr/local/lib/mike-ai/patch-api-mcp-refresh.py
 
 exec hermes gateway run