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.
npx agentmods add skills/peterkrueck/claude-code-development-kit/second-opinionnpx skills add peterkrueck/Claude-Code-Development-Kit --skill second-opiniongit clone --depth 1 https://github.com/peterkrueck/Claude-Code-Development-KitWhat 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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00166 | $0.02199 |
| Opus 5 | $0.00083 | $0.01099 |
| Sonnet 5 | $0.00033 | $0.00440 |
| Haiku 4.5 | $0.00017 | $0.00220 |
Grade A, and why
second-opinion 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 3d 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.
How it starts
The opening of the file, as written. The whole thing — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Second Opinion — OpenAI Codex
Get an independent second opinion from OpenAI's Codex CLI. It uses Codex's default model — a completely different architecture and training run from Claude, which makes it genuinely useful for catching blind spots, validating reasoning on edge cases, or surfacing trade-offs Claude would miss (Claude's own errors tend to be invisible to Claude).
Codex has full read access to the project — it can read files, grep code, and explore the codebase. Its project instructions (AGENTS.md at the repository root) tell it to prime itself on the key docs before answering. You provide the specific question and any focused context; Codex handles the rest.
This is the default second-opinion engine. For a Gemini second opinion specifically, the user invokes the separate second-opinion-gemini skill ("ask Gemini"). When the user says "ask both", run this skill and that one, then synthesize all three views (yours + Codex + Gemini).
When to Use
- Architecture decisions with real trade-offs
- Debugging where you've been going in circles
- Code review on tricky logic or subtle edge cases
- Validating your reasoning before the user acts on it
- When the user explicitly asks for a second opinion
Don't use this for routine tasks — every call takes 10-60+ seconds and consumes ChatGPT-plan quota. Reserve it for decisions where being wrong has real consequences.
Process
Step 1: Prepare the Prompt
Codex has NO access to your conversation history, but it CAN read project files. Structure your prompt as:
- The question — what exactly you want Codex to weigh in on
- Your current thinking (recommended) — share your position so Codex can challenge it
- Relevant area (optional) — if the project has distinct modules or components, state which one this is about so Codex primes on the right docs. Default is the whole project; only narrow this when it helps.
- Specific context (if needed) — pipe code snippets or diffs via stdin when the relevant code is scattered or you want to focus attention on specific sections
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.
- 3d ago First seen · 123 lines · 166 tokens per session scan A 27f9471ecba8
second-opinion is a skill published in the GitHub repository peterkrueck/Claude-Code-Development-Kit (1,380 stars, last pushed 1mo ago), licensed MIT. It adds 166 tokens to every session and 2,199 once invoked, about $0.0008 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 2026-08-30.
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