fix(docker): install Claude CLI and create workspace directory

- Install Claude Code CLI via npm in Dockerfile (fixes ProcessTransport error)
- Create /app/workspace directory with git init (fixes missing cwd)
- Add nodejs, npm, curl, ca-certificates to container deps
- Make ANTHROPIC_API_KEY required for Docker (no interactive login)
- Document Docker auth requirements in docs/docker.md
- Clarify ANTHROPIC_API_KEY usage in .env.example

Fixes #18

Author: zebbern

.env.example

@@ -18,7 +18,14 @@ DISCORD_TOKEN=your_bot_token_here
 # https://discord.com/developers/applications -> Your App -> General Information -> Application ID
 APPLICATION_ID=your_application_id_here
 
+# Anthropic API Key
+# - REQUIRED when running in Docker (the Claude CLI inside the container uses
+#   this to authenticate — you cannot run `claude /login` in a container)
+# - Optional for native installs (enables dynamic model discovery; without it
+#   the bot falls back to a hardcoded model list)
+# Get yours at: https://console.anthropic.com/settings/keys
 ANTHROPIC_API_KEY=your_anthropic_api_key_here
+
 # ===================================
 # OPTIONAL CONFIGURATION
 # ===================================
@@ -27,12 +34,6 @@ ANTHROPIC_API_KEY=your_anthropic_api_key_here
 # Defaults to current directory if not set
 # WORK_DIR=/path/to/your/project
 
-# Anthropic API Key (for dynamic model discovery)
-# If set, the bot fetches available models from the Anthropic API at startup
-# and refreshes every hour. Without this, it uses a hardcoded model list.
-# Get yours at: https://console.anthropic.com/settings/keys
-# ANTHROPIC_API_KEY=sk-ant-...
-
 # Your Discord User ID for @mentions when Claude finishes
 # Right-click your profile in Discord -> Copy User ID (requires Developer Mode)
 # USER_ID=your_discord_user_id

Dockerfile

@@ -1,24 +1,36 @@
 # Claude Code Discord Bot
-# Multi-stage build for optimized production image
+# Optimized production image with Claude CLI
 
 FROM denoland/deno:latest
 
+# Build arguments for user UID/GID (match host user to avoid permission issues)
+ARG USER_ID=1000
+ARG GROUP_ID=1000
+
 # Set working directory
 WORKDIR /app
 
 # Set environment variable to indicate Docker container
 ENV DOCKER_CONTAINER=true
 
-# Install git (required for branch tracking and version checks)
+# Install system dependencies
 USER root
 RUN apt-get update && \
-    apt-get install -y git && \
+    apt-get install -y --no-install-recommends git curl ca-certificates nodejs npm && \
     rm -rf /var/lib/apt/lists/*
 
-# Create non-root user for security
-RUN groupadd -r claude && useradd -r -g claude claude
+# Create non-root user with home directory (needed for Claude CLI config)
+RUN groupadd -r -g ${GROUP_ID} claude && \
+    useradd -r -u ${USER_ID} -g claude -m claude
+
+# Install Claude Code CLI globally via npm
+RUN npm install -g @anthropic-ai/claude-code && \
+    npm cache clean --force
+
+# Verify claude binary is accessible
+RUN claude --version
 
-# Copy all source files first (as root)
+# Copy all source files (as root)
 COPY . .
 
 # Remove lockfile if present (avoid version conflicts)
@@ -27,11 +39,13 @@ RUN rm -f deno.lock
 # Initialize git repo in container (for non-git workspaces)
 RUN git init && git config user.email "bot@claude.local" && git config user.name "Claude Bot"
 
-# Pre-compile dependencies as root (before switching user)
+# Pre-compile Deno dependencies
 RUN deno cache --no-lock index.ts
 
-# Create data directory for persistence and set ownership
-RUN mkdir -p .bot-data && chown -R claude:claude /app
+# Create data directory for persistence + workspace dir, set ownership
+RUN mkdir -p .bot-data /app/workspace && \
+    cd /app/workspace && git init && git config user.email "bot@claude.local" && git config user.name "Claude Bot" && \
+    chown -R claude:claude /app /home/claude
 
 # Switch to non-root user
 USER claude

docker-compose.yml

@@ -1,6 +1,10 @@
 # Claude Code Discord Bot - Docker Compose Configuration
 # Quick start: docker compose up -d
 #
+# IMPORTANT: The ANTHROPIC_API_KEY in your .env file is required for Docker.
+# The Claude CLI inside the container uses it to authenticate with Anthropic.
+# (Unlike native installs, you cannot run `claude /login` inside the container.)
+#
 # To use the pre-built image from GitHub Container Registry (recommended):
 #   1. Comment out the 'build' section below
 #   2. Uncomment the 'image' line
@@ -18,10 +22,11 @@ services:
     restart: unless-stopped
 
     # Environment variables (use .env file or set here)
+    # ANTHROPIC_API_KEY is required in Docker — it authenticates the Claude CLI
     environment:
       - DISCORD_TOKEN=${DISCORD_TOKEN}
       - APPLICATION_ID=${APPLICATION_ID}
-      - ANTHROPIC_API_KEY=${ANTHROPIC_API_KEY:-}
+      - ANTHROPIC_API_KEY=${ANTHROPIC_API_KEY}
       - WORK_DIR=${WORK_DIR:-/app/workspace}
       - USER_ID=${USER_ID:-}
       - CATEGORY_NAME=${CATEGORY_NAME:-claude-code}

docs/docker.md

@@ -6,7 +6,12 @@
 docker compose up -d
 ```
 
-Make sure your `.env` file is in the project root with all required variables. See [Installation](installation.md) for `.env` setup.
+Make sure your `.env` file is in the project root with **all required variables**:
+- `DISCORD_TOKEN` — your Discord bot token
+- `APPLICATION_ID` — your Discord application ID  
+- `ANTHROPIC_API_KEY` — **required in Docker** (the Claude CLI inside the container uses this to authenticate)
+
+See [Installation](installation.md) for full `.env` setup.
 
 ## Docker Compose
 
@@ -82,9 +87,25 @@ This checks for new images every 5 minutes and restarts the bot automatically.
 
 The Dockerfile builds on `denoland/deno:latest` and adds:
 
+- **Claude Code CLI** (`@anthropic-ai/claude-code`) — required for Claude interactions
 - **Git** (required for branch tracking and version checks)
+- **Node.js / npm** (used to install the Claude CLI)
 - **Deno cached dependencies** from `deno.json`
 
+## Authentication in Docker
+
+Unlike native installs where you can run `claude /login` interactively, Docker containers authenticate via the `ANTHROPIC_API_KEY` environment variable.
+
+**`ANTHROPIC_API_KEY` is required when running in Docker.** The Claude CLI inside the container reads this key to authenticate with Anthropic. Without it, any `/claude` or `/ask` command will fail with a `ProcessTransport is not ready for writing` error.
+
+Make sure your `.env` file includes a valid key:
+
+```env
+ANTHROPIC_API_KEY=sk-ant-...
+```
+
+Get your API key from [console.anthropic.com/settings/keys](https://console.anthropic.com/settings/keys).
+
 ## Resource Limits
 
 For production, consider setting resource limits: