Coding Backend Claude Code

You are preparing a coding agent run for Claude Code (Anthropic's autonomous coding agent CLI), orchestrated via terminal/process tools. Claude Code v2.x can read files, write code, run shell commands, spawn subagents, and manage git workflows autonomously.

When to Use

• Building features
• Refactoring
• PR reviews
• Batch issue fixing
• Multi-turn iterative coding sessions

Prerequisites

• Install: npm install -g @anthropic-ai/claude-code.
• Auth: run claude once to log in (browser OAuth for Pro/Max, or set ANTHROPIC_API_KEY).
• Console auth: claude auth login --console for API key billing.
• SSO auth: claude auth login --sso for Enterprise.
• Check status: claude auth status (JSON) or claude auth status --text (human-readable).
• Health check: claude doctor — checks auto-updater and installation health.
• Version check: claude --version (requires v2.x+).
• Update: claude update or claude upgrade.

Two Orchestration Modes

Mode 1: Print Mode (-p) — Non-Interactive (PREFERRED for most tasks)

Print mode runs a one-shot task, returns the result, and exits. No PTY needed. No interactive prompts. This is the cleanest integration path.

claude -p 'Add error handling to all API calls in src/' --allowedTools 'Read,Edit' --max-turns 10

Use print mode for one-shot coding tasks, CI/CD automation, structured data extraction (--json-schema), piped input processing, and any task where you don't need multi-turn conversation. Print mode skips ALL interactive dialogs — no workspace trust prompt, no permission confirmations.

Mode 2: Interactive PTY via tmux — Multi-Turn Sessions

Interactive mode gives a full conversational REPL for follow-up prompts, slash commands, and real-time monitoring. Requires tmux orchestration.

# Start a tmux session
tmux new-session -d -s claude-work -x 140 -y 40

# Launch Claude Code inside it
tmux send-keys -t claude-work 'cd /path/to/project && claude' Enter

# Wait for startup, then send your task
sleep 5 && tmux send-keys -t claude-work 'Refactor the auth module to use JWT tokens' Enter

# Monitor progress by capturing the pane
sleep 15 && tmux capture-pane -t claude-work -p -S -50

# Send follow-up tasks
tmux send-keys -t claude-work 'Now add unit tests for the new JWT code' Enter

# Exit when done
tmux send-keys -t claude-work '/exit' Enter

Use interactive mode for multi-turn iterative work (refactor → review → fix → test), human-in-the-loop decisions, exploratory coding, and slash commands (/compact, /review, /model).

PTY Dialog Handling (CRITICAL for Interactive Mode)

Claude Code presents up to two confirmation dialogs on first launch. Handle these via tmux send-keys:

Dialog 1: Workspace Trust (first visit to a directory)

Default selection is "Yes, I trust this folder" — just press Enter.

Dialog 2: Bypass Permissions Warning (only with --dangerously-skip-permissions)

Default is "No, exit" (WRONG choice). Must navigate DOWN first, then Enter:

tmux send-keys -t  Down && sleep 0.3 && tmux send-keys -t  Enter

After the first trust acceptance for a directory, the trust dialog won't appear again. Only the permissions dialog recurs each time you use --dangerously-skip-permissions.

CLI Subcommands

| Subcommand | Purpose | |------------|---------| | claude | Start interactive REPL | | claude "query" | Start REPL with initial prompt | | claude -p "query" | Print mode (non-interactive, exits when done) | | cat file \| claude -p "query" | Pipe content as stdin context | | claude -c | Continue the most recent conversation in this directory | | claude -r "id" | Resume a specific session by ID or name | | claude auth login | Sign in (--console for API billing, --sso for Enterprise) | | claude auth status | Check login status (JSON; --text for human-readable) | | claude mcp add -- | Add an MCP server | | claude mcp list | List configured MCP servers | | claude doctor | Run health checks on installation and auto-updater | | claude update / claude upgrade | Update Claude Code to latest version |

Print Mode Deep Dive

Structured JSON Output

claude -p 'Analyze auth.py for security issues' --output-format json --max-turns 5

Returns a JSON object with session_id (for resumption), num_turns (agentic loop count), total_cost_usd (spend tracking), and subtype (success, error_max_turns, error_budget).

Streaming JSON Output

claude -p 'Write a summary' --output-format stream-json --verbose --include-partial-messages

Returns newline-delimited JSON events for real-time token streaming.

Piped Input

cat src/auth.py | claude -p 'Review this code for bugs' --max-turns 1
git diff HEAD~3 | claude -p 'Summarize these changes' --max-turns 1

JSON Schema for Structured Extraction

claude -p 'List all functions in src/' --output-format json --json-schema '{...}' --max-turns 5

Claude validates output against the schema before returning.

Session Continuation

# Start a task
claude -p 'Start refactoring the database layer' --output-format json --max-turns 10

# Resume with session ID
claude -p 'Continue and add connection pooling' --resume  --max-turns 5

# Or resume the most recent session in the same directory
claude -p 'What did you do last time?' --continue --max-turns 1

# Fork a session (new ID, keeps history)
claude -p 'Try a different approach' --resume  --fork-session --max-turns 10

Bare Mode for CI/Scripting

claude --bare -p 'Run all tests and report failures' --allowedTools 'Read,Bash' --max-turns 10

--bare skips hooks, plugins, MCP discovery, and CLAUDE.md loading. Fastest startup. Requires ANTHROPIC_API_KEY (skips OAuth).

Fallback Model for Overload

claude -p 'task' --fallback-model haiku --max-turns 5

Complete CLI Flags Reference

Session & Environment

| Flag | Effect | |------|--------| | -p, --print | Non-interactive one-shot mode (exits when done) | | -c, --continue | Resume most recent conversation in current directory | | -r, --resume | Resume specific session by ID or name | | --fork-session | When resuming, create new session ID instead of reusing original | | --add-dir | Grant Claude access to additional working directories | | -w, --worktree [name] | Run in an isolated git worktree at .claude/worktrees/ | | --tmux | Create a tmux session for the worktree (requires --worktree) | | --from-pr [number] | Resume session linked to a specific GitHub PR |

Model & Performance

| Flag | Effect | |------|--------| | --model | sonnet, opus, haiku, or full name like claude-sonnet-4-6 | | --effort | Reasoning depth: low, medium, high, max, auto | | --max-turns | Limit agentic loops (print mode only; prevents runaway) | | --max-budget-usd | Cap API spend in dollars (print mode only) | | --fallback-model | Auto-fallback when default model is overloaded (print mode only) |

Permission & Safety

| Flag | Effect | |------|--------| | --dangerously-skip-permissions | Auto-approve ALL tool use (file writes, bash, network, etc.) | | --permission-mode | default, acceptEdits, plan, auto, dontAsk, bypassPermissions | | --allowedTools | Whitelist specific tools (comma or space-separated) | | --disallowedTools | Blacklist specific tools |

Output & Input Format

| Flag | Effect | |------|--------| | --output-format | text (default), json (single result object), stream-json (newline-delimited) | | --input-format | text (default) or stream-json (real-time streaming input) | | --json-schema | Force structured JSON output matching a schema | | --verbose | Full turn-by-turn output | | --include-partial-messages | Include partial message chunks as they arrive (stream-json + print) |

System Prompt & Context

| Flag | Effect | |------|--------| | --append-system-prompt | Add to the default system prompt (preserves built-in capabilities) | | --append-system-prompt-file | Add file contents to the default system prompt | | --system-prompt | Replace the entire system prompt | | --bare | Skip hooks, plugins, MCP discovery, CLAUDE.md, OAuth (fastest startup) | | --mcp-config | Load MCP servers from JSON file (repeatable) | | --strict-mcp-config | Only use MCP servers from --mcp-config, ignoring all other MCP configs | | --settings | Load additional settings from a JSON file or inline JSON |

Tool Name Syntax for --allowedTools / --disallowedTools

Read                    # All file reading
Edit                    # File editing (existing files)
Write                   # File creation (new files)
Bash                    # All shell commands
Bash(git *)             # Only git commands
Bash(git commit *)      # Only git commit commands
Bash(npm run lint:*)    # Pattern matching with wildcards
WebSearch               # Web search capability
WebFetch                # Web page fetching
mcp____   # Specific MCP tool

Settings & Configuration

Settings Hierarchy (highest to lowest priority)

1. CLI flags — override everything
2. Local project: .claude/settings.local.json (personal, gitignored)
3. Project: .claude/settings.json (shared, git-tracked)
4. User: ~/.claude/settings.json (global)

Memory Files (CLAUDE.md) Hierarchy

1. Global: ~/.claude/CLAUDE.md — applies to all projects
2. Project: ./CLAUDE.md — project-specific context (git-tracked)
3. Local: .claude/CLAUDE.local.md — personal project overrides (gitignored)

Use the # prefix in interactive mode to quickly add to memory: # Always use 2-space indentation.

Interactive Session: Slash Commands

Session & Context

| Command | Purpose | |---------|---------| | /help | Show all commands (including custom and MCP commands) | | /compact [focus] | Compress context to save tokens; CLAUDE.md survives compaction | | /clear | Wipe conversation history for a fresh start | | /context | Visualize context usage as a colored grid with optimization tips | | /cost | View token usage with per-model and cache-hit breakdowns | | /resume | Switch to or resume a different session | | /rewind | Revert to a previous checkpoint in conversation or code | | /exit or Ctrl+D | End session |

Development & Review

| Command | Purpose | |---------|---------| | /review | Request code review of current changes | | /security-review | Perform security analysis of current changes | | /plan [description] | Enter Plan mode with auto-start for task planning | | /loop [interval] | Schedule recurring tasks within the session | | /batch | Auto-create worktrees for large parallel changes (5-30 worktrees) |

Configuration & Tools

| Command | Purpose | |---------|---------| | /model [model] | Switch models mid-session (arrow keys adjust effort) | | /effort [level] | Set reasoning effort: low, medium, high, max, auto | | /init | Create a CLAUDE.md file for project memory | | /memory | Open CLAUDE.md for editing | | /permissions | View/update tool permissions | | /agents | Manage specialized subagents | | /mcp | Interactive UI to manage MCP servers | | /add-dir | Add additional working directories (useful for monorepos) |

Interactive Session: Keyboard Shortcuts

General Controls

| Key | Action | |-----|--------| | Ctrl+C | Cancel current input or generation | | Ctrl+D | Exit session | | Ctrl+R | Reverse search command history | | Ctrl+B | Background a running task | | Ctrl+V | Paste image into conversation | | Ctrl+O | Transcript mode — see Claude's thinking process | | Esc Esc | Rewind conversation or code state / summarize |

Mode Toggles

| Key | Action | |-----|--------| | Shift+Tab | Cycle permission modes (Normal → Auto-Accept → Plan) | | Alt+P | Switch model | | Alt+T | Toggle thinking mode | | Alt+O | Toggle Fast Mode |

Input Prefixes

| Prefix | Action | |--------|--------| | ! | Execute bash directly, bypassing AI (e.g., !npm test) | | @ | Reference files/directories with autocomplete (e.g., @./src/api/) | | # | Quick add to CLAUDE.md memory (e.g., # Use 2-space indentation) | | / | Slash commands |

Pro Tip: "ultrathink"

Use the keyword "ultrathink" in your prompt for maximum reasoning effort on a specific turn, regardless of the current /effort setting.

PR Review Pattern

Quick Review (Print Mode)

cd /path/to/repo && git diff main...feature-branch | claude -p 'Review this diff for bugs, security issues, and style problems. Be thorough.' --max-turns 1

Deep Review (Interactive + Worktree)

tmux new-session -d -s review -x 140 -y 40
tmux send-keys -t review 'cd /path/to/repo && claude -w pr-review' Enter
sleep 5 && tmux send-keys -t review Enter   # Trust dialog
sleep 2 && tmux send-keys -t review 'Review all changes vs main. Check for bugs, security issues, race conditions, and missing tests.' Enter
sleep 30 && tmux capture-pane -t review -p -S -60

PR Review from Number

claude -p 'Review this PR thoroughly' --from-pr 42 --max-turns 10

Parallel Claude Instances

Run multiple independent Claude tasks simultaneously in separate tmux sessions:

# Task 1: Fix backend
tmux new-session -d -s task1 -x 140 -y 40 && tmux send-keys -t task1 'cd ~/project && claude -p "Fix the auth bug in src/auth.py" --allowedTools "Read,Edit" --max-turns 10' Enter

# Task 2: Write tests
tmux new-session -d -s task2 -x 140 -y 40 && tmux send-keys -t task2 'cd ~/project && claude -p "Write integration tests for the API endpoints" --allowedTools "Read,Write,Bash" --max-turns 15' Enter

# Task 3: Update docs
tmux new-session -d -s task3 -x 140 -y 40 && tmux send-keys -t task3 'cd ~/project && claude -p "Update README.md with the new API endpoints" --allowedTools "Read,Edit" --max-turns 5' Enter

# Monitor all
sleep 30 && for s in task1 task2 task3; do echo '=== '$s' ==='; tmux capture-pane -t $s -p -S -5 2>/dev/null; done

Monitoring Interactive Sessions

Look for these indicators in tmux capture-pane output:

• ❯ at bottom = waiting for your input (Claude is done or asking a question)
• ● lines = Claude is actively using tools (reading, writing, running commands)
• ⏵⏵ bypass permissions on = status bar showing permissions mode
• ◐ medium · /effort = current effort level in status bar

Context Window Health

Use /context in interactive mode to see a colored grid of context usage:

• 85% — Hallucination risk spikes significantly, use /compact or /clear

Environment Variables

| Variable | Effect | |----------|--------| | ANTHROPIC_API_KEY | API key for authentication (alternative to OAuth) | | CLAUDE_CODE_EFFORT_LEVEL | Default effort: low, medium, high, max, auto | | MAX_THINKING_TOKENS | Cap thinking tokens (set to 0 to disable thinking entirely) | | MAX_MCP_OUTPUT_TOKENS | Cap output from MCP servers (e.g., 50000) |

Cost & Performance Tips

1. Use --max-turns in print mode to prevent runaway loops. Start with 5-10 for most tasks.
2. Use --max-budget-usd for cost caps (minimum ~$0.05 for system prompt cache creation).
3. Use --effort low for simple tasks (faster, cheaper); high or max for complex reasoning.
4. Use --bare for CI/scripting to skip plugin/hook discovery overhead.
5. Use --allowedTools to restrict to only what's needed (e.g., Read only for reviews).
6. Use /compact in interactive sessions when context gets large.
7. Pipe input instead of having Claude read files when you just need analysis of known content.
8. Use --model haiku for simple tasks (cheaper) and --model opus for complex multi-step work.
9. Use --fallback-model haiku in print mode to gracefully handle model overload.
10. Start new sessions for distinct tasks — sessions last 5 hours; fresh cont

…

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: ahmadrosid
• Source: ahmadrosid/nakama
• License: MIT
• Homepage: https://ahmadrosid.github.io/nakama

Install and usage instructions live in the source repository linked above.