coding-agent

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# Coding Agent (bash-first)

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

## ⚠️ PTY Mode: required for Codex/Pi/OpenCode

These agents are interactive terminal apps and need a pseudo-terminal:

```bash
# ✅ Correct
bash pty:true 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                                |

---

## Quick Start: One-Shot Tasks

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

```bash
# 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.

---

## The Pattern: workdir + background + pty

For longer tasks, use background mode with PTY:

```bash
# 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.

---

## 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

```bash
# 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 your main project folder!**
Clone to temp folder or use git worktree.

```bash
# Clone to temp for safe review
REVIEW_DIR=$(mktemp -d)
git clone https://github.com/user/repo.git $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

From freire19/Mythos, MIT.

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