harden

harden is a skill for Claude Code, Codex from VoxTechnologies/transmute-framework. It costs 85 tokens per session (3,366 once invoked), scanned A, original, MIT.

A project-wide review for error handling, failed network requests, unusual inputs, and other edge cases—situations outside the normal path.

In plain words
What is it for?
Use it to review and improve retries, recovery from network failures, circuit breakers, race conditions, rate limits for data changes, and edge-case handling.
Why use it?
It helps find places where software may crash, lose data, or leave users without a useful recovery when something goes wrong.

Skill for Claude CodeCodex

Part of the transmuter plugin — 23 skills, 1 command, 7 agents shipped together

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.

agentmods
npx agentmods add skills/voxtechnologies/transmute-framework/harden
Any agent
npx skills add VoxTechnologies/transmute-framework --skill harden
Clone the repo
git clone --depth 1 https://github.com/VoxTechnologies/transmute-framework

Made for: Claude Code, Codex.

Or install transmuter, the plugin that ships this one along with the rest of its 23 skills, 1 command, 7 agents.

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 harden

README.md
[![agentmods](https://agentmods.dev/badge/skills/voxtechnologies/transmute-framework/harden.svg)](https://agentmods.dev/skills/voxtechnologies/transmute-framework/harden)
Your own site
<a href="https://agentmods.dev/skills/voxtechnologies/transmute-framework/harden"><img src="https://agentmods.dev/badge/skills/voxtechnologies/transmute-framework/harden.svg" alt="Measured on agentmods" height="20"></a>
Per session 85 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,366 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found 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 $0.00085 $0.03366
Opus 5 $0.00043 $0.01683
Sonnet 5 $0.00017 $0.00673
Haiku 4.5 $0.00009 $0.00337

Measured 4d ago against content hash 9c0a4d74d16b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

harden scanned grade A with 0 findings 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 4d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/harden/SKILL.md · 175 lines

How it starts

The opening of the file, as written. The whole thing — 175 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Stage 6G: Error Handling, Network Failures, and Edge Cases

Read the detailed guide at ${CLAUDE_SKILL_ROOT}/references/harden-detailed-guide.md for the complete hardening procedures, teammate spawn prompts, error pattern catalogs, and report templates.

Lead a multi-agent error resilience hardening project. Systematically review the COMPLETE product for error handling gaps, network failure scenarios, race conditions, and edge cases that individual feature implementations may have missed.

Stage Sequence (recommended ordering): Stage 5B → 6A/6B/6C (parallel) → 6E (Code Refactoring) → 6F (Seed Data) → 6G (this stage) → 6D (Documentation) → 6H (Pre-Launch) → 6V → 6R → 6P/6P-R → 7 (Deploy)

Rate Limiting Scope Boundary (6A vs 6G)

Cross-stage coordination: Before implementing data-mutation rate limiting, read ./plancasting/_audits/security/report.md from Stage 6A to verify which endpoints are already rate-limited (auth endpoints). Implement only DATA-MUTATION rate limiting here — auth endpoint rate limiting was handled in 6A.

Stage 6A implements rate limiting for AUTH endpoints (login, signup, password reset, forgot password / password reset initiation, MFA, session management, password change, email verification, invitation acceptance). Stage 6G (this stage) implements rate limiting for DATA-MUTATION endpoints (create, update, delete operations, file uploads, user profile updates). Verify 6A's auth-endpoint rate limiting before implementing to avoid duplication.

Prerequisites

Prerequisite: Stage 6E must have completed before 6G starts — 6G depends on refactored error handling patterns from 6E. Do NOT run 6E and 6G in parallel.

Verify before starting:

  1. ./plancasting/_audits/implementation-completeness/report.md exists with PASS or CONDITIONAL PASS. If missing, STOP: "Stage 5B report not found — do not harden code with unverified implementation completeness."
  2. If 5B shows FAIL, STOP. If CONDITIONAL PASS, review Category C issues and proceed with awareness.
  3. ./plancasting/_audits/refactoring/report.md (6E) exists. If missing, WARN: "Stage 6E not completed. 6G is RECOMMENDED after 6E for cleaner error handling patterns." If present, read the "Extracted Error Handling Patterns for Stage 6G" section to reuse existing patterns rather than creating duplicates.
  4. Read ./CLAUDE.md and ./plancasting/tech-stack.md for project conventions.
  5. If ./plancasting/_audits/security/report.md (6A) is available, include in teammate prompts for rate limiting scope boundaries. If missing, WARN and implement data-mutation rate limiting regardless.

Read the full file on GitHub · 175 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. 4d ago First seen · 175 lines · 85 tokens per session scan A 9c0a4d74d16b

Subscribe to this mod's changes

harden is a skill published in the GitHub repository VoxTechnologies/transmute-framework (4 stars, last pushed 1mo ago), licensed MIT. It adds 85 tokens to every session and 3,366 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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