reason

A command for asking Codex to examine a difficult question and compare possible approaches.

In plain words
What is it for?
Use it for architecture choices, technical trade-offs, and other problems where several solutions need comparison.
Why use it?
It helps organize complex reasoning, trade-offs, and recommendations when a quick answer is not enough.

Command

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 commands/rachittshah/cc-codex/reason
Clone the repo
git clone --depth 1 https://github.com/rachittshah/cc-codex
Per session 11 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 502 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 $0.00011 $0.00502
Opus 5 $0.00005 $0.00251
Sonnet 5 $0.00002 $0.00100
Haiku 4.5 $0.00001 $0.00050

Measured 2d ago against content hash a4452dbc64f6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

reason 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 2d 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.

commands/reason.md · 94 lines

How it starts

The opening of the file, as written. The whole thing — 94 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Deep Reasoning Analysis

Your task

You are receiving a request for deep reasoning and analysis using Codex's advanced reasoning capabilities.

Steps

  1. Understand the Question: Extract the core question or problem from the user's request

  2. Call Codex Reasoning Tool:

    • Use the mcp__codex__codex_reason tool
    • Provide the question clearly
    • Include any relevant context
    • Pass session ID for context sharing
  3. Process the Analysis:

    • Parse the structured reasoning output
    • Present analysis, considerations, and approaches clearly
    • Highlight the recommendation and rationale
    • Show trade-offs transparently
  4. Facilitate Decision:

    • Ask if the user agrees with the recommendation
    • Offer to explore alternative approaches
    • Suggest concrete next steps

Example Usage

User: "/reason should we use REST or GraphQL for our API?"

Expected flow:

  1. Call codex_reason with the architectural question
  2. Receive analysis with multiple approaches evaluated
  3. Present structured comparison
  4. Ask: "Based on this analysis, shall we proceed with [recommendation]?"

Notes

  • Use for architectural decisions, trade-off analysis, complex problems
  • Codex provides multi-perspective analysis
  • Present all options fairly, even if one is recommended
  • Store reasoning as session artifact for future reference

Output Format

Present the reasoning like this:

# Reasoning: [Question]

## Analysis
[Detailed examination of the problem]

## Key Considerations

### [Factor 1] (Impact: High/Medium/Low)
[Description]

### [Factor 2] (Impact: High/Medium/Low)
[Description]

## Approaches Evaluated

### Approach 1: [Name]
**Complexity**: Low/Medium/High

**Pros**:
- [Pro 1]
- [Pro 2]

**Cons**:
- [Con 1]
- [Con 2]

### Approach 2: [Name]
[... same structure ...]

## Recommendation
[Recommended approach]

## Rationale
[Detailed reasoning for the recommendation]

---

Does this analysis align with your thinking? Ready to move forward with [recommendation]?

Read the full file on GitHub · 94 lines

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. 2d ago First seen · 94 lines · 11 tokens per session scan A a4452dbc64f6

Subscribe to this mod's changes

reason is a command published in the GitHub repository rachittshah/cc-codex (11 stars, last pushed 10mo ago), licensed Apache-2.0. It adds 11 tokens to every session and 502 once invoked, about $0.0001 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.