decision-log

decision-log is a skill for Claude Code from xdg/xdg-claude. It costs 83 tokens per session (1,064 once invoked), scanned A, original, Apache-2.0.

A record of important engineering choices kept in the project repository. Each entry explains what was chosen, when, why, and which alternatives were rejected.

In plain words
What is it for?
Use it to document choices about dependencies, versions, system design, communication rules, security trade-offs, deliberate omissions, or reversals.
Why use it?
It stops future contributors from reopening settled decisions or undoing them without understanding the reasons. The written history preserves context that may not be clear from the code alone.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions CLAUDE.md; mentions AGENTS.md.

Part of the decision-log plugin — 1 skill shipped together

Good fit Use it to document choices about dependencies, versions, system design, communication rules, security trade-offs, deliberate omissions, or reversals.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/xdg/xdg-claude/decision-log
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 xdg/xdg-claude --skill decision-log
Clone the repo
git clone --depth 1 https://github.com/xdg/xdg-claude

Made for: Claude Code.

Or install decision-log, the plugin that ships this one along with the rest of its 1 skill.

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/xdg/xdg-claude/decision-log/github.svg)](https://agentmods.dev/skills/xdg/xdg-claude/decision-log)
Your own site
<a href="https://agentmods.dev/skills/xdg/xdg-claude/decision-log"><img src="https://agentmods.dev/badge/skills/xdg/xdg-claude/decision-log/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 decision-log

Your own site · 80×15
<a href="https://agentmods.dev/skills/xdg/xdg-claude/decision-log"><img src="https://agentmods.dev/badge/skills/xdg/xdg-claude/decision-log.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 83 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,064 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 warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Excessive Agency · line 38
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
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 $0.00083 $0.01064
Opus 5 $0.00042 $0.00532
Sonnet 5 $0.00017 $0.00213
Haiku 4.5 $0.00008 $0.00106

Measured 9d ago against content hash 34a4e66626bc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, 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 9d 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.

decision-log/skills/decision-log/SKILL.md · 105 lines

How it starts

The opening of the file, as written. The whole thing — 105 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Decision log

An append-only log of choices with teeth: what was decided, when, and why the alternatives lost. It exists so a future reader — the user, a contributor, or a later session — does not relitigate a settled question or silently undo it.

What earns an entry

Log a decision when all of these hold:

  • Real alternatives existed and one was chosen.
  • The choice constrains future work, or a future reader would otherwise be tempted to change it back.
  • The reasoning is not recoverable from the diff alone.

Typical: dependency and version pins, protocol/interface choices, deployment topology, deliberate omissions ("no X, because the pinned version cannot"), security trade-offs, and reversals of earlier entries.

Not log-worthy: refactors, renames, formatting, bug fixes, anything the code plus a commit message already explains. A log padded with trivia stops being read.

Where the log lives

  1. If the project's CLAUDE.md (or AGENTS.md) names a decision-log path, use it.
  2. Otherwise docs/decisions.md.
  3. If that is absent, check for DECISIONS.md, doc/decisions.md, or an adr/ / docs/adr/ directory before concluding there is none.

Before writing, verify the ground

Never create a decision log, and never restructure an existing one, without asking the user first. Many repos -- especially ones the user does not own -- have their own conventions or want none of this.

  • Log exists and follows the template below — append. No need to ask.
  • Log exists but uses a different format (ADR-per-file, a table, numbered records) — follow that repo's format. Match its headings, numbering, and field names. Do not convert it to this template.
  • Log exists and is formatted ambiguously — show the user one existing entry and ask whether to match it or use this skill's template.
  • No log anywhere — stop and ask: "This repo has no decision log. Start one at <path>?" Take no action on a refusal, and do not re-ask in that session.

Read the full file on GitHub · 105 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. 9d ago First seen · 105 lines · 83 tokens per session scan A 34a4e66626bc

Subscribe to this mod's changes

decision-log is a skill published in the GitHub repository xdg/xdg-claude (20 stars, last pushed 2d ago), licensed Apache-2.0. It adds 83 tokens to every session and 1,064 once invoked, about $0.0004 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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