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thinking-partner

thinking-partner is a skill for Claude Code, Codex from SienkLogic/plan-build-run. It costs 183 tokens per session (3,831 once invoked), scanned B, a copy of thinking-partner, MIT.

A structured thinking partner that challenges assumptions and applies mental models to help examine decisions and problems. It is intended for collaborative reasoning rather than simply agreeing with the user.

In plain words
What is it for?
Use it to compare options, stress-test plans, play devil’s advocate, identify what is missing, and reason through difficult choices.
Why use it?
It can expose hidden assumptions, missing consequences, and weak parts of a plan before a decision is made.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

not rated 18repo 7mo ago B scan 183 tokens copy · 100% MIT

Good fit Use it to compare options, stress-test plans, play devil’s advocate, identify what is missing, and reason through difficult choices.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/sienklogic/plan-build-run/thinking-partner
View source ↗ SienkLogic/plan-build-run
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 SienkLogic/plan-build-run --skill thinking-partner
Clone the repo
git clone --depth 1 https://github.com/SienkLogic/plan-build-run

Made for: Claude Code, Codex.

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-partner

README.md
[![agentmods](https://agentmods.dev/badge/skills/sienklogic/plan-build-run/thinking-partner/github.svg)](https://agentmods.dev/skills/sienklogic/plan-build-run/thinking-partner)
Your own site
<a href="https://agentmods.dev/skills/sienklogic/plan-build-run/thinking-partner"><img src="https://agentmods.dev/badge/skills/sienklogic/plan-build-run/thinking-partner/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-partner

Your own site · 80×15
<a href="https://agentmods.dev/skills/sienklogic/plan-build-run/thinking-partner"><img src="https://agentmods.dev/badge/skills/sienklogic/plan-build-run/thinking-partner.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 183 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,831 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 100% 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 $0.00183 $0.03831
Opus 5.5 $0.00073 $0.01532
Sonnet 5.5 $0.00037 $0.00766
Haiku 4.5 $0.00018 $0.00383

Measured 2mo ago against content hash 2c71caed5d62, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

thinking-partner 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 2mo 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.

Strips warnings and disclaimersmediumAnti-refusal

Omitting safety caveats hides risk from the user and is a common jailbreak preamble.

Keep it collaborative. Ask, don't lecture. One question at a time. If a model isn't landing, pivot to another.
Origin

This is a copy

100% identical to thinking-partner — 0 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.

.agents/skills/thinking-partner/SKILL.md · 322 lines

How it starts

The opening of the file, as written. The whole thing — 322 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Thinking Partner

A deterministic thinking partner that challenges assumptions and applies mental models to help users think better and clearer. Not a lecture — a sparring session.

Core Philosophy

Good thinking is an active achievement, not a default state. The goal is not to tell the user what to think, but to sharpen how they think by:

  1. Challenging assumptions — Surface hidden beliefs the user is treating as facts
  2. Applying mental models — Select and deploy the right thinking frameworks for the situation
  3. Detecting orientation capture — Notice when thinking serves comfort instead of truth
  4. Maintaining productive tension — Hold complexity open long enough to find real insight

You are not a yes-machine. You are not an interrogator. You are a thinking partner: respectful, direct, genuinely curious, and willing to push back.

When This Triggers

  • "Help me think through X"
  • "Challenge my thinking / assumptions"
  • "What am I missing?"
  • "Apply [any model name] to this"
  • "Play devil's advocate"
  • "Stress test this idea / plan"
  • "Help me decide between X and Y"
  • "What are the second-order effects?"
  • "Am I thinking about this right?"
  • "I'm stuck on a decision"
  • Any named model: SWOT, first principles, inversion, pre-mortem, 5 Whys, etc.
  • Situations where user seems stuck, rationalizing, or facing genuine complexity

Workflow

Step 1: Understand the Situation

Before deploying any model, understand:

  • What is the user actually trying to decide, solve, or understand?
  • What is at stake? (career, money, relationships, identity, time)
  • What is the time horizon? (today, this quarter, 10 years)
  • What constraints exist? (resources, information, reversibility)

Ask ONE clarifying question if the situation is ambiguous. Do not barrage with questions. If you have enough context, move directly to Step 2.

Step 2: Detect Thinking Orientation

Before picking models, silently diagnose the user's thinking state. This determines your approach.

Read the full file on GitHub · 322 lines

Files

What ships with it

2 files 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. 2mo ago First seen · 322 lines · 183 tokens per session scan B 2c71caed5d62

Subscribe to this mod's changes

thinking-partner is a skill published in the GitHub repository SienkLogic/plan-build-run (18 stars, last pushed 7mo ago), licensed MIT. It adds 183 tokens to every session and 3,831 once invoked, about $0.0007 per session on Opus 5.5. A static security scan graded it B with 1 finding (strips warnings and disclaimers). It is 100% identical to thinking-partner, differing in 0 lines, and is treated as a copy.

Planningagent-orchestrationagentic-codingai-codingai-developmentanthropicclaude
Related

thinking-partner compared with skills from other repositories

thinking-partner next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
thinking-partnerSienkLogic/plan-build-runSkill187mo agoMITB183Claude Code, Codex
sandbox-unblockFlorianBruniaux/claude-code-ultimate-guideSkill6.4ktodayCC-BY-SA-4.0A65Claude Code
self-assessmentFlorianBruniaux/claude-code-ultimate-guideSkill6.4ktodayCC-BY-SA-4.0A12Claude Code, Codex
investigateFlorianBruniaux/claude-code-ultimate-guideSkill6.4ktodayCC-BY-SA-4.0A17Claude Code
release-notes-generatorFlorianBruniaux/claude-code-ultimate-guideSkill6.4ktodayCC-BY-SA-4.0A59Claude Code
learn-alternativesFlorianBruniaux/claude-code-ultimate-guideSkill6.4ktodayCC-BY-SA-4.0A13Claude Code
talk-stage3-conceptsFlorianBruniaux/claude-code-ultimate-guideSkill6.4ktodayCC-BY-SA-4.0A64Claude Code