sequential-thinking

A structured method for solving complex problems through numbered thoughts that can be revised, extended, or split into alternative branches.

In plain words
What is it for?
Use it to break down difficult tasks, plan designs, analyze uncertain problems, and revise earlier decisions before reaching an answer.
Why use it?
It provides a record of the reasoning process and makes it easier to adjust the plan when new information changes the direction.

Skill for Claude CodeCodex

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/thedotmack/sequential-thinking-skill/sequential-thinking
Any agent
npx skills add thedotmack/sequential-thinking-skill --skill sequential-thinking
Clone the repo
git clone --depth 1 https://github.com/thedotmack/sequential-thinking-skill

Made for: Claude Code, Codex.

Per session 152 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,487 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 $0.00152 $0.01487
Opus 5 $0.00076 $0.00744
Sonnet 5 $0.00030 $0.00297
Haiku 4.5 $0.00015 $0.00149

Measured 2d ago against content hash 72bd15c72de3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

sequential-thinking 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.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/think.ts), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

sequential-thinking/SKILL.md · 152 lines

How it starts

The opening of the file, as written. The whole thing — 152 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Sequential Thinking

A tool for dynamic, reflective problem-solving through a chain of numbered thoughts. Full parity with the Sequential Thinking MCP server — same parameters, same state management, same behavioral contract.

How to Use This Skill

When this skill is activated, use scripts/think.ts as your primary reasoning mechanism. Do not reason in prose — reason through the script. Every step of your analysis should be a thought submitted via the script, making your reasoning chain explicit and trackable.

Workflow

  1. Reset state at the start of every new thinking session
  2. Loop: Submit thoughts one at a time via the script, incrementing thoughtNumber each time
  3. Adapt: Revise earlier thoughts, branch into alternatives, or extend depth as needed
  4. Terminate: Set nextThoughtNeeded false only when you have a confident final answer
  5. Respond: After the final thought, provide the answer to the user

Each thought should be a single Bash tool call. Think in the thought, not outside it.

Script Location

scripts/think.ts

Run via bun from the skill's base directory.

Commands

Reset (required before every new session)

bun scripts/think.ts --reset

Submit a Thought

Required flags: --thought, --thoughtNumber, --totalThoughts, --nextThoughtNeeded

bun scripts/think.ts \
  --thought "Your analysis for this step" \
  --thoughtNumber 1 \
  --totalThoughts 5 \
  --nextThoughtNeeded true

Submit a Revision

Revises a previous thought. The original stays in history; the revision is appended as a new entry. Requires --isRevision and --revisesThought.

bun scripts/think.ts \
  --thought "Corrected analysis" \
  --thoughtNumber 3 \
  --totalThoughts 5 \
  --nextThoughtNeeded true \
  --isRevision --revisesThought 1

Submit a Branch

Explores an alternative path from a prior thought. Requires both --branchFromThought and --branchId.

bun scripts/think.ts \
  --thought "Alternative approach" \
  --thoughtNumber 4 \
  --totalThoughts 7 \
  --nextThoughtNeeded true \
  --branchFromThought 2 --branchId alt-approach

Read the full file on GitHub · 152 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. 2d ago First seen · 152 lines · 152 tokens per session scan A 72bd15c72de3

Subscribe to this mod's changes

sequential-thinking is a skill published in the GitHub repository thedotmack/sequential-thinking-skill (38 stars, last pushed 6mo ago), licensed MIT. It adds 152 tokens to every session and 1,487 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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