diff --git a/Dockerfile.claude b/Dockerfile.claude
index cb568f1f..3aa260fa 100644
--- a/Dockerfile.claude
+++ b/Dockerfile.claude
@@ -10,9 +10,12 @@ RUN touch src/main.rs && cargo build --release
 FROM node:22-bookworm-slim
 RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates curl procps ripgrep && rm -rf /var/lib/apt/lists/*
 
-# Install claude-agent-acp adapter and Claude Code CLI
+# Install claude-agent-acp adapter and Claude Code CLI.
+# Without CLAUDE_CODE_EXECUTABLE the adapter uses its own bundled SDK cli.js,
+# ignoring the globally installed claude-code binary (see #418).
 ARG CLAUDE_CODE_VERSION=2.1.104
 RUN npm install -g @agentclientprotocol/claude-agent-acp@0.25.0 @anthropic-ai/claude-code@${CLAUDE_CODE_VERSION} --retry 3
+ENV CLAUDE_CODE_EXECUTABLE=/usr/local/bin/claude
 
 # Install gh CLI
 RUN curl -fsSL https://cli.github.com/packages/githubcli-archive-keyring.gpg \