Guides product-market fit (PMF) validation and measurement. PMF occurs when a product precisely meets market needs, creating widespread demand. ~99% of startups fail primarily due to PMF issues (vitamin problems, premature scaling). Use this skill when validating before scaling, measuring PMF, or diagnosing traction problems.

When invoking: On first use, if helpful, open with 1–2 sentences on what this skill covers and why it matters, then provide the main output. On subsequent use or when the user asks to skip, go directly to the main output.

Product-market fit (Marc Andreessen): "Being in a good market with a product that can satisfy that market."

Signals: Customers buying rapidly; usage growing; word-of-mouth spreading organically; high retention, low churn.

Question: "How would you feel if you could no longer use [product]?"

Threshold: 40%+ answering "very disappointed" = PMF achieved. Below 40% = iterate.

Best practice: Survey 40–50 active users (used product 2+ times in last 14 days). Segment by user type—some segments may have PMF while others don't.

Limitation: Combine with retention curves, engagement, organic growth; avoid false positives in early stages.

~99% of failures: Solving vitamin problems instead of real pain. Validate: Would users be genuinely inconvenienced if your product vanished?

Validation: Talk to users; listen for frustration; run pre-sells; check frequency and time-sensitivity of the problem.

Use: When discussing PMF for SaaS or enterprise—factor in product research rigor and ACV-specific challenges. See gtm-strategy for enterprise GTM.

PMF is increasingly a continuous validation—markets evolve; re-measure as you expand. Target "PMF for a niche" first (40%+ in one segment) before broadening.