don-cheli-sdd: Skill for Claude Code

.agent/skills/doncheli-reasoning/SKILL.md

doncheli-reasoning is a skill for Claude Code from doncheli/don-cheli-sdd. It costs 61 tokens per session (594 once invoked), scanned A, original, Apache-2.0.

A set of structured ways to think through decisions and problems. It includes methods such as pre-mortems, which imagine how a plan could fail, and 5 Whys, which traces a problem to its root cause.

In plain words
What is it for?
Analyzing decisions, finding root causes, breaking down complex problems, checking assumptions, and comparing possible outcomes.
Why use it?
It helps turn vague thinking into a clear examination of risks, causes, consequences, trade-offs, and uncertainty.

Skill for Claude Code

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

This is doncheli/don-cheli-sdd's own configuration. It tells Claude Code how to work on don-cheli-sdd itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything don-cheli-sdd configures →

Part of the don-cheli-sdd plugin — 28 skills, 115 commands, 1 agent shipped together

Reuse

Borrowing it

Nothing to install: this file belongs to doncheli/don-cheli-sdd. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/doncheli/don-cheli-sdd/main/.agent/skills/doncheli-reasoning/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/doncheli/don-cheli-sdd

Made for: Claude Code.

Or install don-cheli-sdd, the plugin that ships this one along with the rest of its 28 skills, 115 commands, 1 agent.

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 doncheli-reasoning

README.md
[![agentmods](https://agentmods.dev/badge/skills/doncheli/don-cheli-sdd/doncheli-reasoning/github.svg)](https://agentmods.dev/skills/doncheli/don-cheli-sdd/doncheli-reasoning)
Your own site
<a href="https://agentmods.dev/skills/doncheli/don-cheli-sdd/doncheli-reasoning"><img src="https://agentmods.dev/badge/skills/doncheli/don-cheli-sdd/doncheli-reasoning/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 doncheli-reasoning

Your own site · 80×15
<a href="https://agentmods.dev/skills/doncheli/don-cheli-sdd/doncheli-reasoning"><img src="https://agentmods.dev/badge/skills/doncheli/don-cheli-sdd/doncheli-reasoning.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 61 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 594 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 $0.00061 $0.00594
Opus 5 $0.00030 $0.00297
Sonnet 5 $0.00012 $0.00119
Haiku 4.5 $0.00006 $0.00059

Measured 11d ago against content hash 64b4f39ac7a6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

doncheli-reasoning 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 11d 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.

.agent/skills/doncheli-reasoning/SKILL.md · 61 lines

How it starts

The opening of the file, as written. The whole thing — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Don Cheli: Structured Reasoning Engine

Available Models

ID Best For
pre-mortem Imagining failure before it happens; surfacing hidden risks
5-whys Root cause analysis of a known problem
pareto Identifying the 20% of causes driving 80% of impact
inversion Asking "what would guarantee failure?" to find blockers
second-order Mapping downstream consequences of a decision
first-principles Decomposing assumptions down to fundamental truths
minimize-regret Choosing the option you will regret least in 10 years
opportunity-cost Evaluating what you give up by choosing this option
circle-of-competence Assessing whether you have the knowledge to decide well
map-territory Separating your mental model from reality
probabilistic Assigning probabilities to outcomes; expected-value calc
reversibility Classifying decisions as one-way vs. two-way doors
rlm-chain-of-thought Step-by-step explicit reasoning (RLM: PrimeIntellect style)
rlm-decomposition Breaking a complex problem into atomic sub-problems (RLM)
rlm-verification Self-checking the reasoning chain for contradictions (RLM)

Instructions

  1. Read the problem or decision description
  2. If the user did not specify a model, suggest the 1–2 best-fit models with a one-line rationale; wait for confirmation or proceed with the top suggestion
  3. Apply the selected model(s) rigorously, showing all reasoning steps
  4. End with a clear recommendation or insight

Output Format

## Reasoning: <problem>
**Model applied:** <id> — <why this model fits>

### Analysis
<step-by-step application of the model>

### Insight / Recommendation
…

### Caveats
…

Read the full file on GitHub · 61 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. 11d ago First seen · 61 lines · 61 tokens per session scan A 64b4f39ac7a6

Subscribe to this mod's changes

doncheli-reasoning is a skill published in the GitHub repository doncheli/don-cheli-sdd (57 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 61 tokens to every session and 594 once invoked, about $0.0003 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.