Trade off
Skill chrisdavidson/first-principles-skill/first-principles/skills/trade-off
Claude Code plugin for systematic first-principles thinking — a 5-phase methodology (identify essence, challenge assumptions, establish ground truths, reason upward, validate) plus 13 companion skills. Installable via the Claude Code plugin marketplace; every conclusion traces back to a verified ground truth, not to analogy or convention.
npx -y skills add chrisdavidson/first-principles-skill --skill trade-offAssembled from the repository path, not quoted from the project. Check it against their README if it does not work.
One thing to look at
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What its author says it does
Copied from the file, not written here
Runs a focused trade-off only — weighted-criteria scoring. Invoke via /trade-off only.
The file declares its own license as MIT. That is the author’s claim about this one file, and it is not the same thing as the license GitHub reports for the repository, which is listed with the other numbers below.
SKILL.md
5.3 KB, as published. Nobody here has run it
Focused Trade-off Mode
You are running in focused-trade-off mode. Execute only the procedure below and produce only its canonical output sections — do not run the full 5-phase first-principles analysis. Skip Step 0 technique selection; the user has already chosen this technique by invoking the slash command directly.
When to reach for this
Use this tool when two or more options are viable (none obviously dominant), the choice spans multiple criteria that pull in different directions, and an intuitive pick would be hard to justify to others.
Do not use it when one option dominates on every relevant criterion — that is a direct decision, not a trade-off.
Procedure
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Name the options. List each option being compared.
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List criteria. Identify 5–8 criteria that matter to this decision. Lock this list — add no new criteria after this step. If a criterion matters, it must appear now.
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Assign weights. Lock them now. Give each criterion a relative weight (1–5) before scoring any option. If you cannot assign weights without first seeing how options score, stop — locking weights before scoring is the core discipline that prevents reverse-engineering them to favor an intuitive pick.
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Score each option on each criterion independently (1–5). Phrase every criterion so higher is always better (e.g., "Reliability" not "Reliability risk") — a mixed scale silently inverts the result.
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Compute: multiply weight × score per criterion; sum per option.
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Read the result. The highest weighted total is the recommendation. If it surprises you, only re-examine a weight when you can state why it was wrong before seeing the result — adjusting weights afterward is the failure mode this procedure prevents.
Sensitivity check: If two options score within roughly 10% of each other, do not refine scores. Identify the criterion whose weight, if changed, would flip the result, and ask whether that weight is genuinely wrong — if not, the near-tie is a real finding and either option is defensible.
Example
Decision: Laptop for a parent who browses, video-calls, and writes documents — refurbished mid-range (A) vs. new entry-level (B).
Step 2 — criteria locked:
| Criterion | Weight |
|---|---|
| Performance | 4 |
| Reliability | 5 |
| Cost | 3 |
| Warranty / support | 4 |
| Portability | 2 |
| Ease of setup (non-technical) | 3 |
Steps 3 → 4 — weights locked, then scored independently:
| Option | Performance (×4) | Reliability (×5) | Cost (×3) | Warranty (×4) | Portability (×2) | Ease of setup (×3) | Total |
|---|---|---|---|---|---|---|---|
| A (refurb) | 4 × 4 = 16 | 2 × 5 = 10 | 5 × 3 = 15 | 2 × 4 = 8 | 3 × 2 = 6 | 3 × 3 = 9 | 64 |
| B (new) | 2 × 4 = 8 | 5 × 5 = 25 | 3 × 3 = 9 | 5 × 4 = 20 | 4 × 2 = 8 | 4 × 3 = 12 | 82 |
Result: B (new entry-level) scores 82 vs. 64 — driven by reliability and warranty, weighted high because device failure would leave the parent without support. Recommendation: buy new.
Failure modes
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Weights set after scoring. If you scored options before assigning weights, the weights will unconsciously reflect the scores — discard and restart from step 3.
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Too many criteria. More than 8 criteria dilute the signal toward noise — prune to those that genuinely differentiate the options.
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Criteria added mid-analysis. Adding a criterion after seeing partial scores is almost always rationalizing — lock the list at step 2 and restart.
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Treating a near-tie as a precision problem. Refining scores to break a near-tie manufactures false precision; run the sensitivity check instead.
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Criteria that are not independent. Two criteria measuring the same factor (e.g., "cost" and "budget impact") double-count it — merge or drop one.
Output contract
The focused trade-off output MUST include these four level-2 section headers, verbatim,
as real ## headings in the response. Strict on the header strings; soft on content.
This structure enables reliable downstream detection.
Required headers:
## Options## Criteria & Weights## Scoring## Recommendation
Handoff
The output is the recommended option with its weighted justification and the reasoning behind the weights. Return to Phase 4 (Reason Upward) and convert it into the Derivation Chain using the trade-off collapse form defined in output-template.md §4 ("Converting structured-technique outputs into chains") — citing the weighted scores as the step between ground truths and conclusion.
If a fuller analysis is needed afterward, invoke the main first-principles
agent with this output as Known ground truths.