Coding Agent (bash-first)

Use bash (with optional background mode) for all coding agent work. Simple and effective.

⚠️ PTY Mode Required!

Coding agents (Codex, Claude Code, Pi) are interactive terminal applications that need a pseudo-terminal (PTY) to work correctly. Without PTY, you'll get broken output, missing colors, or the agent may hang.

Always use pty:true when running coding agents:

# ✅ Correct - with PTY
bash pty:true command:"codex exec 'Your prompt'"

# ❌ Wrong - no PTY, agent may break
bash command:"codex exec 'Your prompt'"

Bash Tool Parameters

Parameter

Type

Description

command	string	The shell command to run
pty	boolean	Use for coding agents! Allocates a pseudo-terminal for interactive CLIs
workdir	string	Working directory (agent sees only this folder's context)
background	boolean	Run in background, returns sessionId for monitoring
timeout	number	Timeout in seconds (kills process on expiry)
elevated	boolean	Run on host instead of sandbox (if allowed)

Process Tool Actions (for background sessions)

Action

Description

list	List all running/recent sessions
poll	Check if session is still running
log	Get session output (with optional offset/limit)
write	Send raw data to stdin
submit	Send data + newline (like typing and pressing Enter)
send-keys	Send key tokens or hex bytes
paste	Paste text (with optional bracketed mode)
kill	Terminate the session

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Quick Start: One-Shot Tasks

For quick prompts/chats, create a temp git repo and run:

# Quick chat (Codex needs a git repo!)
SCRATCH=$(mktemp -d) && cd $SCRATCH && git init && codex exec "Your prompt here"

# Or in a real project - with PTY!
bash pty:true workdir:~/Projects/myproject command:"codex exec 'Add error handling to the API calls'"

Why git init? Codex refuses to run outside a trusted git directory. Creating a temp repo solves this for scratch work.

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The Pattern: workdir + background + pty

For longer tasks, use background mode with PTY:

# Start agent in target directory (with PTY!)
bash pty:true workdir:~/project background:true command:"codex exec --full-auto 'Build a snake game'"
# Returns sessionId for tracking

# Monitor progress
process action:log sessionId:XXX

# Check if done
process action:poll sessionId:XXX

# Send input (if agent asks a question)
process action:write sessionId:XXX data:"y"

# Submit with Enter (like typing "yes" and pressing Enter)
process action:submit sessionId:XXX data:"yes"

# Kill if needed
process action:kill sessionId:XXX

Why workdir matters: Agent wakes up in a focused directory, doesn't wander off reading unrelated files (like your soul.md 😅).

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Fallback Strategy

When primary agent hits limits, fall back in order:

Priority

Agent

When to Use

1	Codex	Default for coding tasks
2	Claude Code	Codex usage limits or errors
3	Gemini	Claude unavailable or for Gemini-specific tasks
4	Pi/OpenCode	All above unavailable

Signs you need to fall back:

• "You've hit your usage limit"
• Rate limit / 429 errors
• Model overloaded messages

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Codex CLI

Model: gpt-5.2-codex is the default (set in ~/.codex/config.toml)

Flags

Flag

Effect

exec "prompt"	One-shot execution, exits when done
--full-auto	Sandboxed but auto-approves in workspace
--yolo	NO sandbox, NO approvals (fastest, most dangerous)

Building/Creating

# Quick one-shot (auto-approves) - remember PTY!
bash pty:true workdir:~/project command:"codex exec --full-auto 'Build a dark mode toggle'"

# Background for longer work
bash pty:true workdir:~/project background:true command:"codex --yolo 'Refactor the auth module'"

Reviewing PRs

⚠️ CRITICAL: Never review PRs in Moltbot's own project folder!
Clone to temp folder or use git worktree.

# Clone to temp for safe review
REVIEW_DIR=$(mktemp -d)
git clone  $REVIEW_DIR
cd $REVIEW_DIR && gh pr checkout 130
bash pty:true workdir:$REVIEW_DIR command:"codex review --base origin/main"
# Clean up after: trash $REVIEW_DIR

# Or use git worktree (keeps main intact)
git worktree add /tmp/pr-130-review pr-130-branch
bash pty:true workdir:/tmp/pr-130-review command:"codex review --base main"

Batch PR Reviews (parallel army!)

# Fetch all PR refs first
git fetch origin '+refs/pull/*/head:refs/remotes/origin/pr/*'

# Deploy the army - one Codex per PR (all with PTY!)
bash pty:true workdir:~/project background:true command:"codex exec 'Review PR #86. git diff origin/main...origin/pr/86'"
bash pty:true workdir:~/project background:true command:"codex exec 'Review PR #87. git diff origin/main...origin/pr/87'"

# Monitor all
process action:list

# Post results to GitHub
gh pr comment <PR#> --body "<review content>"

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Claude Code

Fallback when Codex unavailable.

Codex

Claude Equivalent

codex exec "prompt"	claude -p "prompt"
codex --full-auto	claude -p --permission-mode acceptEdits
codex --yolo	claude -p --dangerously-skip-permissions

# Non-interactive
claude -p "Add error handling to src/api.ts"
claude -p --permission-mode acceptEdits "Fix the bug"

# Interactive (with PTY)
bash pty:true workdir:~/project command:"claude 'Your task'"

Detailed docs: See references/claude-code.md

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Gemini CLI

Alternative fallback with different model family.

Codex

Gemini Equivalent

codex exec "prompt"	gemini "prompt"
codex --full-auto	gemini --approval-mode auto_edit "prompt"
codex --yolo	gemini -y "prompt"

# Non-interactive (one-shot)
gemini "Add error handling to src/api.ts"
gemini -y "Build a REST API"  # yolo mode

# Interactive (with PTY)
bash pty:true workdir:~/project command:"gemini -i 'Your task'"

Detailed docs: See references/gemini-cli.md

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OpenCode

bash pty:true workdir:~/project command:"opencode run 'Your task'"

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Pi Coding Agent

# Install: npm install -g @mariozechner/pi-coding-agent
bash pty:true workdir:~/project command:"pi 'Your task'"

# Non-interactive mode (PTY still recommended)
bash pty:true command:"pi -p 'Summarize src/'"

# Different provider/model
bash pty:true command:"pi --provider openai --model gpt-4o-mini -p 'Your task'"

Note: Pi now has Anthropic prompt caching enabled (PR #584, merged Jan 2026)!

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Parallel Issue Fixing with git worktrees

For fixing multiple issues in parallel, use git worktrees:

# 1. Create worktrees for each issue
git worktree add -b fix/issue-78 /tmp/issue-78 main
git worktree add -b fix/issue-99 /tmp/issue-99 main

# 2. Launch Codex in each (background + PTY!)
bash pty:true workdir:/tmp/issue-78 background:true command:"pnpm install && codex --yolo 'Fix issue #78: <description>. Commit and push.'"
bash pty:true workdir:/tmp/issue-99 background:true command:"pnpm install && codex --yolo 'Fix issue #99: <description>. Commit and push.'"

# 3. Monitor progress
process action:list
process action:log sessionId:XXX

# 4. Create PRs after fixes
cd /tmp/issue-78 && git push -u origin fix/issue-78
gh pr create --repo user/repo --head fix/issue-78 --title "fix: ..." --body "..."

# 5. Cleanup
git worktree remove /tmp/issue-78
git worktree remove /tmp/issue-99

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tmux Orchestration (Alternative)

For advanced multi-agent control, use the tmux skill instead of bash background mode.

When to Use tmux vs bash background

Use Case

Recommended

Quick one-shot tasks	bash pty:true
Long-running with monitoring	bash background:true
Multiple parallel agents	tmux
Agent forking (context transfer)	tmux
Session persistence (survives disconnects)	tmux
Interactive debugging (pdb, REPL)	tmux

Quick Example

SOCKET="${TMPDIR:-/tmp}/coding-agents.sock"

# Create sessions for parallel work
tmux -S "$SOCKET" new-session -d -s agent-1 -c /tmp/worktree-1
tmux -S "$SOCKET" new-session -d -s agent-2 -c /tmp/worktree-2

# Launch agents
tmux -S "$SOCKET" send-keys -t agent-1 "codex --yolo 'Fix issue #1'" Enter
tmux -S "$SOCKET" send-keys -t agent-2 "claude 'Fix issue #2'" Enter

# Monitor (check for shell prompt to detect completion)
tmux -S "$SOCKET" capture-pane -p -t agent-1 -S -100

# Attach to watch live
tmux -S "$SOCKET" attach -t agent-1

Agent Forking

Transfer context between agents (e.g., plan with Codex, execute with Claude):

# Capture context from current agent
CONTEXT=$(tmux -S "$SOCKET" capture-pane -p -t planner -S -500)

# Fork to new agent with context
tmux -S "$SOCKET" new-session -d -s executor
tmux -S "$SOCKET" send-keys -t executor "claude -p 'Based on this plan: $CONTEXT

Execute step 1.'" Enter

Full docs: See the tmux skill for socket conventions, wait-for-text helpers, and cleanup.

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⚠️ Rules

Always use pty:true - coding agents need a terminal!

Respect tool choice - if user asks for Codex, use Codex.

- Orchestrator mode: do NOT hand-code patches yourself.
- If an agent fails/hangs, respawn it or ask the user for direction, but don't silently take over.

Be patient - don't kill sessions because they're "slow"

Monitor with process:log - check progress without interfering

--full-auto for building - auto-approves changes

vanilla for reviewing - no special flags needed

Parallel is OK - run many Codex processes at once for batch work

NEVER start Codex in ~/clawd/ - it'll read your soul docs and get weird ideas about the org chart!

NEVER checkout branches in ~/Projects/moltbot/ - that's the LIVE Moltbot instance!

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Progress Updates (Critical)

When you spawn coding agents in the background, keep the user in the loop.

• Send 1 short message when you start (what's running + where).
• Then only update again when something changes:

- a milestone completes (build finished, tests passed) - the agent asks a question / needs input - you hit an error or need user action - the agent finishes (include what changed + where)

• If you kill a session, immediately say you killed it and why.

This prevents the user from seeing only "Agent failed before reply" and having no idea what happened.

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Auto-Notify on Completion

For long-running background tasks, append a wake trigger to your prompt so Moltbot gets notified immediately when the agent finishes (instead of waiting for the next heartbeat):

... your task here.

When completely finished, run this command to notify me:
moltbot gateway wake --text "Done: [brief summary of what was built]" --mode now

Example:

bash pty:true workdir:~/project background:true command:"codex --yolo exec 'Build a REST API for todos.

When completely finished, run: moltbot gateway wake --text \"Done: Built todos REST API with CRUD endpoints\" --mode now'"

This triggers an immediate wake event — Skippy gets pinged in seconds, not 10 minutes.

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Learnings (Jan 2026)

• PTY is essential: Coding agents are interactive terminal apps. Without pty:true, output breaks or agent hangs.
• Git repo required: Codex won't run outside a git directory. Use mktemp -d && git init for scratch work.
• exec is your friend: codex exec "prompt" runs and exits cleanly - perfect for one-shots.
• submit vs write: Use submit to send input + Enter, write for raw data without newline.
• Sass works: Codex responds well to playful prompts. Asked it to write a haiku about being second fiddle to a space lobster, got: "Second chair, I code / Space lobster sets the tempo / Keys glow, I follow" 🦞