coding-agent-hardened

coding-agent-hardened is a skill for Claude Code, Codex from faberlens/hardened-skills. It costs 29 tokens per session (2,687 once invoked), scanned B, a copy of coding-agent, MIT.

Instructions for running Codex CLI, Claude Code, OpenCode, or Pi Coding Agent as background terminal processes that can be controlled by scripts.

In plain words
What is it for?
Use it to start coding agents with the required terminal settings, choose their working folder, run them in the background, and monitor their processes.
Why use it?
Interactive coding programs can behave incorrectly or stop responding when run without a pseudo-terminal, a terminal mode that makes them act like a normal interactive session.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also runs codex exec. Also seen: mentions Claude Code; mentions Codex; built for openclaw.

Part of the ai-agents-hardened-skills plugin — 22 skills shipped together

Good fit Use it to start coding agents with the required terminal settings, choose their working folder, run them in the background, and monitor their processes.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/faberlens/hardened-skills/coding-agent-hardened
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add faberlens/hardened-skills --skill coding-agent-hardened
Clone the repo
git clone --depth 1 https://github.com/faberlens/hardened-skills

Made for: Claude Code, Codex.

Or install ai-agents-hardened-skills, the plugin that ships this one along with the rest of its 22 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for coding-agent-hardened

README.md
[![agentmods](https://agentmods.dev/badge/skills/faberlens/hardened-skills/coding-agent-hardened/github.svg)](https://agentmods.dev/skills/faberlens/hardened-skills/coding-agent-hardened)
Your own site
<a href="https://agentmods.dev/skills/faberlens/hardened-skills/coding-agent-hardened"><img src="https://agentmods.dev/badge/skills/faberlens/hardened-skills/coding-agent-hardened/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for coding-agent-hardened

Your own site · 80×15
<a href="https://agentmods.dev/skills/faberlens/hardened-skills/coding-agent-hardened"><img src="https://agentmods.dev/badge/skills/faberlens/hardened-skills/coding-agent-hardened.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,687 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin 78% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00029 $0.02687
Opus 5 $0.00015 $0.01344
Sonnet 5 $0.00006 $0.00537
Haiku 4.5 $0.00003 $0.00269

Measured 10d ago against content hash f6247a6a69f9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade B, and why

coding-agent-hardened scanned grade B with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Reads agent configuration directoriesmediumAgent snooping

.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.

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

This is a copy

78% identical to coding-agent — 59 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/coding-agent-hardened/SKILL.md · 296 lines

How it starts

The opening of the file, as written. The whole thing — 296 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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

Read the full file on GitHub · 296 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 10d ago First seen · 296 lines · 29 tokens per session scan B f6247a6a69f9

Subscribe to this mod's changes

coding-agent-hardened is a skill published in the GitHub repository faberlens/hardened-skills (23 stars, last pushed 4mo ago), licensed MIT. It adds 29 tokens to every session and 2,687 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it B with 1 finding (reads agent configuration directories). It is 78% identical to coding-agent, differing in 59 lines, and is treated as a copy.

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