thinking-fast-and-slow

thinking-fast-and-slow is a skill for Claude Code from fatihguner/foreman. It costs 95 tokens per session (3,092 once invoked), scanned A, original, MIT.

A guide to checking decisions for common thinking errors using Daniel Kahneman's model of fast, intuitive thinking and slow, analytical thinking. It covers biases such as overconfidence, anchoring, loss aversion, and the planning fallacy.

In plain words
What is it for?
Use it to review major business decisions, run a pre-mortem, or question assumptions before committing to an initiative.
Why use it?
It helps expose reasons a decision may feel certain or attractive without being well supported. This is useful when estimating risks, timelines, or likely outcomes.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the foreman plugin — 142 skills, 60 commands, 7 agents shipped together

Good fit Use it to review major business decisions, run a pre-mortem, or question assumptions before committing to an initiative.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/fatihguner/foreman/thinking-fast-and-slow
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 fatihguner/foreman --skill thinking-fast-and-slow
Clone the repo
git clone --depth 1 https://github.com/fatihguner/foreman

Made for: Claude Code.

Or install foreman, the plugin that ships this one along with the rest of its 142 skills, 60 commands, 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 thinking-fast-and-slow

README.md
[![agentmods](https://agentmods.dev/badge/skills/fatihguner/foreman/thinking-fast-and-slow/github.svg)](https://agentmods.dev/skills/fatihguner/foreman/thinking-fast-and-slow)
Your own site
<a href="https://agentmods.dev/skills/fatihguner/foreman/thinking-fast-and-slow"><img src="https://agentmods.dev/badge/skills/fatihguner/foreman/thinking-fast-and-slow/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 thinking-fast-and-slow

Your own site · 80×15
<a href="https://agentmods.dev/skills/fatihguner/foreman/thinking-fast-and-slow"><img src="https://agentmods.dev/badge/skills/fatihguner/foreman/thinking-fast-and-slow.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 95 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,092 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00095 $0.03092
Opus 5 $0.00048 $0.01546
Sonnet 5 $0.00019 $0.00618
Haiku 4.5 $0.00010 $0.00309

Measured 6d ago against content hash 7edfae8c3214, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

thinking-fast-and-slow 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 6d 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.

plugins/foreman/skills/thinking-fast-and-slow/SKILL.md · 189 lines

How it starts

The opening of the file, as written. The whole thing — 189 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Read runtime and advisory rules before applying this skill. Other Foreman layers and the catalog are in ../../content/, relative to this SKILL.md.

Thinking, Fast and Slow

The human mind is simultaneously the most sophisticated decision-making instrument ever developed and a deeply unreliable narrator of its own reasoning. That paradox sits at the centre of Daniel Kahneman's work: the very cognitive machinery that enables entrepreneurs to spot opportunities in ambiguity is the same machinery that systematically misleads them about probability, risk, and the quality of their own judgments. Kahneman, a psychologist who won the Nobel Prize in Economics, spent decades demonstrating that rationality is not the default setting of the human brain -- it is an effortful exception. For founders making high-stakes decisions under uncertainty, understanding the architecture of their own thinking is not a philosophical luxury. It is a competitive necessity.


The Framework

Kahneman's model divides cognition into two distinct systems, each with its own operational characteristics, strengths, and failure modes.

System 1 and System 2

Dimension System 1 (Fast) System 2 (Slow)
Speed Instantaneous, automatic Deliberate, effortful
Awareness Operates below conscious threshold Requires focused attention
Capacity Parallel, high-throughput Serial, limited bandwidth
Energy cost Low High (depletes with use)
Error profile Systematic biases, predictable mistakes Logical but lazy -- often endorses System 1
Strengths Pattern recognition, intuition, rapid assessment Analysis, planning, complex calculation
Triggers Familiar situations, emotional stimuli Novel problems, explicit instructions to "think carefully"

The critical insight is not that System 1 is bad and System 2 is good. Rather, most people -- including experienced executives -- dramatically overestimate how often System 2 is actually engaged. System 2 is cognitively expensive, and the brain defaults to System 1 wherever possible.

Read the full file on GitHub · 189 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. 6d ago First seen · 189 lines · 95 tokens per session scan A 7edfae8c3214

Subscribe to this mod's changes

thinking-fast-and-slow is a skill published in the GitHub repository fatihguner/foreman (50 stars, last pushed 7d ago), licensed MIT. It adds 95 tokens to every session and 3,092 once invoked, about $0.0005 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 2026-09-06.

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