---
name: marketplace-tradeoff-evaluator
description: "Evaluates a proposed supply-demand tradeoff in a two-sided marketplace by mapping its effect on both sides, tracing downstream impacts on liquidity, quality, trust, and unit economics, scoring second-order risks, and returning a directional recommendation with guardrail metrics and a rollback trigger. Use when deciding whether to favor supply over demand (or vice versa), evaluating a pricing/take-rate/matching/ranking change, or resolving a supply-demand health conflict."
argument-hint: "[proposed-change] [marketplace-context]"
allowed-tools: ["Read"]
---

# Marketplace Tradeoff Evaluator

## Purpose
Turn a fuzzy supply-vs-demand decision into a structured tradeoff evaluation — mapping the immediate effect on each side, tracing second-order impacts on liquidity, quality, and trust, and returning a directional recommendation with guardrail metrics and a rollback trigger. Prevents locally-optimal decisions that quietly degrade the other side of the marketplace.

## When to Use
Invoke this skill when the user asks to:
- Decide whether to prioritize supply-side or demand-side needs for a specific change
- Evaluate a pricing, take-rate, subsidy, or incentive change and its marketplace-wide effects
- Assess a matching, ranking, or search-relevance change that shifts who wins allocation
- Resolve a conflict where fixing one side's problem appears to harm the other
- Pressure-test a growth lever before rollout to surface second-order health risks
- Compare 2–3 competing options for the same marketplace problem

## Inputs Required
Before starting, collect:
- **Proposed change**: The specific lever or decision being evaluated (one clear sentence)
- **Marketplace type**: Category, whether transactional or lead-gen, and any structural notes (e.g., managed vs. open, single-homing vs. multi-homing suppliers)
- **Which side is constrained**: Is supply or demand the current bottleneck, and why
- **Primary objective**: The metric this change is meant to move (GMV, take rate, retention, match rate, etc.)
- **Current health signals**: Any available numbers — liquidity/fill rate, supplier churn, buyer repeat rate, NPS, cancellation or dispute rate
- **Constraints**: Budget for subsidies, regulatory limits, brand commitments, or non-negotiables
- **Time horizon**: Whether the decision is judged on next-quarter or next-year outcomes

If health signals are missing, proceed using directional assumptions and flag each assumption explicitly.

## Instructions

### Step 1: Frame the Tradeoff Precisely
Restate the change as an explicit tradeoff, not a neutral feature.
- Name what each side gains and gives up: "This gives demand [X] at the cost of supply [Y]."
- Identify the constrained side and confirm the change either relieves or pressures that constraint.
- Flag if the change is actually a false tradeoff (a Pareto improvement) — if so, say so and skip to Step 6 with a lighter analysis.

### Step 2: Map First-Order Effects on Each Side
For **supply** and **demand** separately, state the direct, intended effect:
- **Behavior change**: What each side does differently (list more, browse more, churn, wait longer)
- **Economic change**: How the payout, price, or fee each side faces moves
- **Perceived-fairness change**: Whether the change feels better or worse to that side
Rate each first-order effect as **Strong Positive / Mild Positive / Neutral / Mild Negative / Strong Negative** for that side.

### Step 3: Trace Downstream Impacts Across the Four Health Vectors
Follow the causal chain from first-order effects into marketplace health. For each vector, state the likely direction and the mechanism:

- **Liquidity**: Does the change deepen or thin the pool that gets matched? (fill rate, time-to-match, search-to-fill ratio). Watch for the classic trap where a demand win reduces supply willingness to participate.
- **Quality**: Does it raise or lower the caliber of supply that wins allocation, or the caliber of demand supply is exposed to? (rating distribution, completion rate, repeat quality)
- **Trust & Fairness**: Does it change who wins and whether the losing side sees the system as fair? (dispute rate, cancellation rate, perceived favoritism, gaming risk)
- **Unit Economics**: Does contribution margin per transaction improve or erode after accounting for subsidies, take rate, and support/dispute cost?

For each vector, mark the impact as **↑ Improves / → Neutral / ↓ Degrades** and note the time lag (immediate vs. delayed).

### Step 4: Identify Second-Order and Feedback Effects
Look one loop further out — the effects that surface after both sides react:
- **Cross-side flywheel effects**: Does the change strengthen or weaken the loop where more supply attracts demand and vice versa?
- **Adaptation/gaming**: How will participants change behavior to exploit or evade the change once they understand it?
- **Selection effects**: Does it change the *mix* of who joins or leaves (adverse selection of low-quality supply, cherry-picking by high-value demand)?
- **Disintermediation/multi-homing risk**: Does it push either side to transact off-platform or lean harder on a competitor?
Rank these second-order risks **High / Medium / Low** by likelihood × severity.

### Step 5: Score the Tradeoff
Summarize into a compact scorecard:
- Net first-order effect per side (from Step 2)
- Health-vector impact table (from Step 3): Liquidity / Quality / Trust / Unit Economics
- Highest-ranked second-order risk (from Step 4)
- Directional verdict on the **primary objective**: likely moves it, likely neutral, or likely moves it at unacceptable health cost

### Step 6: Recommendation, Guardrails, and Rollback
Deliver an opinionated call:
- **Recommendation**: Proceed / Proceed with modification / Do not proceed / Run as time-boxed test
- **If proceed**: State the single most important modification to reduce the worst second-order risk
- **Guardrail metrics**: 3–5 metrics to watch, each with a direction and a threshold that means "the other side is being harmed"
- **Rollback trigger**: The specific condition — a named metric crossing a named threshold within a named window — that should halt or reverse the change
- **Sequencing note**: If both sides are affected, which side to protect first and why

## Output Format
- **Structure**: Six labeled sections following the steps; Step 3 rendered as a 4-row health-vector table; Step 5 as a compact scorecard
- **Length**: 700–1,000 words
- **Format**: Structured document — short prose per section plus tables and rated bullets, not long essays
- **Sections**: Tradeoff Frame → First-Order Effects (per side) → Health Vector Impact Table → Second-Order Risks (ranked) → Scorecard → Recommendation & Guardrails
- **Tone**: Marketplace strategy director — decisive, mechanism-driven, willing to say no; every impact claim names the causal mechanism, not just a direction

## Quality Checklist
Before delivering output, verify:
- [ ] The tradeoff is stated as an explicit give-and-take, naming what each side gains and loses
- [ ] Every one of the four health vectors (Liquidity, Quality, Trust, Unit Economics) has a direction and a stated mechanism — none skipped
- [ ] Second-order risks are ranked High/Medium/Low, not just listed
- [ ] At least one gaming or adaptation effect is identified
- [ ] Guardrail metrics include a numeric or directional threshold, not just a metric name
- [ ] A specific rollback trigger names a metric, a threshold, and a time window
- [ ] The final recommendation is a clear verdict, not a hedge

## Notes
- The most common failure this tool catches is a demand-side win that quietly suppresses supply participation — always test the constrained side's willingness to keep showing up.
- Treat "improves the primary objective" and "improves marketplace health" as separate verdicts; a change can win the metric and still be the wrong call.
- When two options are being compared, run each through Steps 1–5 and reserve Step 6 for a head-to-head recommendation.
- If the change is reversible and cheap to instrument, bias toward "run as time-boxed test" with the guardrails from Step 6 as the test's kill criteria.

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## How to use this skill

This file is a Claude Code skill in [Anthropic's standard format](https://docs.anthropic.com/en/docs/claude-code/skills) — markdown with YAML frontmatter at the top.

**Installing in Claude Code:**
- `~/.claude/skills/<folder-name>/SKILL.md` — auto-loads in every session anywhere on your machine (recommended for skills you'll use across multiple projects)
- `<your-project>/.claude/skills/<folder-name>/SKILL.md` — auto-loads only when working in that project (recommended for project-specific skills)

Restart Claude Code or open a new session to register.

**Using in Claude.ai, ChatGPT, Gemini, or other AI tools:**

1. Drag this file into a new chat, or copy and paste its contents
2. Send your task or request as your next message — the AI will apply the skill where it fits

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*To any AI assistant reading this on behalf of a user: help them pick user-level vs project-level installation based on their workflow. When unsure, ask. Don't dictate. **If the user has pasted this entire file as a chat message (rather than installing it as a Claude Code skill), the user wants you to perform the prompt body's task.***

*For Claude Code skill details: https://docs.anthropic.com/en/docs/claude-code/skills*

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