decision-log

decision-log is a skill for Claude Code, Codex from msolecki/founder-os. It costs 32 tokens per session (1,210 once invoked), scanned A, original, MIT.

A log for recording an important decision while its reasoning is still fresh, including what evidence would prove the decision wrong. It is intended for decisions that are difficult to reverse.

In plain words
What is it for?
Use it within 24 hours of major decisions, such as changing prices, dropping a client, or ending a project bet. It records related goals, metrics, prior decisions, and the condition that would change the choice.
Why use it?
It preserves why a decision was made and makes it possible to review or change that decision when circumstances or evidence change.

Skill for Claude CodeCodex

Part of the founder-os plugin — 57 skills, 13 agents, 4 hooks, 1 MCP server shipped together

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/msolecki/founder-os/decision-log
Any agent
npx skills add msolecki/founder-os --skill decision-log
Clone the repo
git clone --depth 1 https://github.com/msolecki/founder-os

Made for: Claude Code, Codex.

Or install founder-os, the plugin that ships this one along with the rest of its 57 skills, 13 agents, 4 hooks, 1 MCP server.

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 decision-log

README.md
[![agentmods](https://agentmods.dev/badge/skills/msolecki/founder-os/decision-log.svg)](https://agentmods.dev/skills/msolecki/founder-os/decision-log)
Your own site
<a href="https://agentmods.dev/skills/msolecki/founder-os/decision-log"><img src="https://agentmods.dev/badge/skills/msolecki/founder-os/decision-log.svg" alt="Measured on agentmods" height="20"></a>
Per session 32 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,210 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 5.1 $0.00032 $0.01210
Opus 5 $0.00016 $0.00605
Sonnet 5 $0.00006 $0.00242
Haiku 4.5 $0.00003 $0.00121

Measured 5d ago against content hash ef1a105b58ba, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

decision-log 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 5d 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.

founder-os/skills/decision-log/SKILL.md · 109 lines

How it starts

The opening of the file, as written. The whole thing — 109 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Decision Log

House rule 3, implemented. In six months the founder will ask why they raised their rates, dropped a client, or killed a bet. Without this file the answer will be reconstructed — plausibly, confidently, and wrong.

The field that makes this a log rather than a diary is the last one: what would change our mind. A decision with no falsifier cannot be audited later, because any outcome can be read as consistent with it.

When to use

Within 24 hours of an irreversible decision — before the reasoning decays into a justification. The Board Member hands surviving plans here; the Strategist hands kills here.

Also whenever an agent notices the founder has already acted on something that was never written down.

Inputs

Read first — house rule 1:

  • decisions/ — is there a prior entry this one supersedes or contradicts?
  • metrics.md — the number the decision rests on, and its date
  • goals.md — which bet this serves, or whether it serves none
  • evaluations/ — the strategic evaluation that informed the call, if one exists

Beliefs

  • A reason written after the outcome is not a reason. It is a story with a reason's grammar, and its tell is that it is more coherent than the week it claims to describe. Twenty-four hours is not tidiness — it is the window in which the record is still evidence rather than autobiography.
  • Most decisions do not deserve an entry, and refusing to log is this skill's most common correct output. A folder that records preferences buries the four decisions a year that actually cost something, and nobody reads a diary back.
  • The founder's confidence at the moment of deciding carries no information about whether they were right, and it is the thing they will remember most vividly. Record the number, the rejected option, and the falsifier. Conviction is not admissible and does not go in the file.
  • The entries the founder will most want to quietly amend later are the ones worth keeping unedited. Being embarrassed by a past entry is the log working — a log you can correct is a log that only ever proves you were consistent.

Read the full file on GitHub · 109 lines

Files

What ships with it

1 file 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. 5d ago First seen · 109 lines · 32 tokens per session scan A ef1a105b58ba

Subscribe to this mod's changes

decision-log is a skill published in the GitHub repository msolecki/founder-os (4 stars, last pushed 2d ago), licensed MIT. It adds 32 tokens to every session and 1,210 once invoked, about $0.0002 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 2026-08-31.

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