agent.sh

agent.sh

#!/bin/bash

# Simple bash-based agent that can call shell commands via OpenAI API
# Requires: curl, jq, OPENAI_API_KEY environment variable

set -e

API_URL="https://api.openai.com/v1/chat/completions"
MODEL="gpt-5"
CONVERSATION_FILE="/tmp/agent_conversation_$$.json"

# Initialize conversation with system message and tools
cat > "$CONVERSATION_FILE" <<'EOF'
{
  "model": "gpt-5",
  "messages": [
    {
      "role": "system",
      "content": "You are a helpful assistant that can execute shell commands. When you need to run a command, use the execute_shell tool. Always explain what you're doing before executing commands."
    }
  ],
  "tools": [
    {
      "type": "function",
      "function": {
        "name": "execute_shell",
        "description": "Execute a shell command and return its output",
        "parameters": {
          "type": "object",
          "properties": {
            "command": {
              "type": "string",
              "description": "The shell command to execute"
            }
          },
          "required": ["command"]
        }
      }
    }
  ]
}
EOF

# Function to execute shell command
execute_shell() {
    local cmd="$1"
    echo "🔧 Executing: $cmd" >&2
    output=$(eval "$cmd" 2>&1) || true
    echo "$output"
}

# Function to add message to conversation
add_message() {
    local role="$1"
    local content="$2"
    
    local temp_file=$(mktemp)
    jq --arg role "$role" --arg content "$content" \
       '.messages += [{role: $role, content: $content}]' \
       "$CONVERSATION_FILE" > "$temp_file"
    mv "$temp_file" "$CONVERSATION_FILE"
}

# Function to add tool call response
add_tool_response() {
    local tool_call_id="$1"
    local output="$2"
    
    local temp_file=$(mktemp)
    jq --arg tool_call_id "$tool_call_id" --arg output "$output" \
       '.messages += [{role: "tool", tool_call_id: $tool_call_id, content: $output}]' \
       "$CONVERSATION_FILE" > "$temp_file"
    mv "$temp_file" "$CONVERSATION_FILE"
}

# Function to add assistant message with tool calls
add_assistant_with_tools() {
    local response="$1"
    
    local temp_file=$(mktemp)
    jq --argjson response "$response" \
       '.messages += [$response]' \
       "$CONVERSATION_FILE" > "$temp_file"
    mv "$temp_file" "$CONVERSATION_FILE"
}

# Function to call OpenAI API
call_api() {
    local payload=$(jq -c '.' "$CONVERSATION_FILE")
    
    response=$(curl -s "$API_URL" \
        -H "Content-Type: application/json" \
        -H "Authorization: Bearer $OPENAI_API_KEY" \
        -d "$payload")
    
    echo "$response"
}

# Main interaction loop
echo "🤖 Simple Bash Agent (type 'exit' or 'quit' to end)"
echo "================================================"

while true; do
    # Get user input
    echo ""
    echo -n "You: "
    read -r user_input
    
    # Check for exit
    if [[ "$user_input" == "exit" ]] || [[ "$user_input" == "quit" ]]; then
        echo "👋 Goodbye!"
        rm -f "$CONVERSATION_FILE"
        exit 0
    fi
    
    # Skip empty input
    if [[ -z "$user_input" ]]; then
        continue
    fi
    
    # Add user message
    add_message "user" "$user_input"
    
    # Agent loop - keep calling API until we get a final response
    while true; do
        # Call API
        api_response=$(call_api)
        
        # Check for API errors
        if echo "$api_response" | jq -e '.error' > /dev/null 2>&1; then
            error_msg=$(echo "$api_response" | jq -r '.error.message')
            echo "❌ API Error: $error_msg" >&2
            break
        fi
        
        # Extract the assistant's message
        assistant_msg=$(echo "$api_response" | jq '.choices[0].message')
        finish_reason=$(echo "$api_response" | jq -r '.choices[0].finish_reason')
        
        # Check if there are tool calls
        tool_calls=$(echo "$assistant_msg" | jq '.tool_calls // []')
        tool_calls_count=$(echo "$tool_calls" | jq 'length')
        
        if [[ "$tool_calls_count" -gt 0 ]]; then
            # Add assistant message with tool calls
            add_assistant_with_tools "$assistant_msg"
            
            # Execute each tool call
            for i in $(seq 0 $((tool_calls_count - 1))); do
                tool_call=$(echo "$tool_calls" | jq ".[$i]")
                tool_call_id=$(echo "$tool_call" | jq -r '.id')
                function_name=$(echo "$tool_call" | jq -r '.function.name')
                arguments=$(echo "$tool_call" | jq -r '.function.arguments')
                
                if [[ "$function_name" == "execute_shell" ]]; then
                    command=$(echo "$arguments" | jq -r '.command')
                    output=$(execute_shell "$command")
                    add_tool_response "$tool_call_id" "$output"
                fi
            done
            
            # Continue loop to get next response
            continue
        else
            # No tool calls, this is the final response
            content=$(echo "$assistant_msg" | jq -r '.content // ""')
            
            if [[ -n "$content" ]]; then
                echo ""
                echo "Agent: $content"
                
                # Add assistant message to conversation
                add_message "assistant" "$content"
            fi
            
            break
        fi
    done
done