Read the pressure on a market before you commit to it.
Describe an industry and where you sit in it. Your assistant rates rivalry, supplier power, buyer power, substitutes and new entrants, shows which way each force is moving, judges how attractive the market is, and names the forces your strategy has to answer.
Original instructions by Pawel Huryn (phuryn/pm-skills), kept byte for byte.
The run’s verdict: “Moderate to somewhat unattractive for a small entrant.” Buyer power and substitutes drive churn; position matters more than the industry average.
These are rules written in the Skill’s instructions, not performance claims.
What it is
A single instruction file that turns a capable AI assistant into a competitive strategist. It walks through each of Porter’s five forces with explicit “high when / low when” conditions, so a rating has visible reasons instead of a gut feel.
It does not stop at five ratings. The assistant rates overall industry attractiveness, picks the 2–3 forces that matter most, and proposes how to reduce strong forces, use weak ones, position the product and turn that into initiatives.
Who it is for
- Product managers sizing up a market before a roadmap bet.
- Founders and operators asking whether a market is worth entering or defending.
- Strategy and consulting teams needing a structured first draft.
- Students and analysts learning to apply the framework with discipline.
Works well for
- Judging whether an industry is attractive for your company
- Market-entry and expansion discussions
- Finding where margin is being squeezed: suppliers, buyers or substitutes
- Pairing with SWOT and PESTLE for a fuller picture
Not designed for
- Market sizing, valuations or financial forecasts
- Live competitor data; it uses what you supply or your assistant can find
- Antitrust, legal or regulatory determinations
- Replacing customer interviews or due diligence
What you provide, what you receive
You provide
- Industry or market definition
- Current competitors and their positioning
- Supplier and customer landscape
- Potential substitutes and new entrants
- Product or service specifics
You receive
- A High / Medium / Low rating for each force
- State, trend, key dynamics and profit impact per force
- An industry attractiveness rating
- The 2–3 most critical forces
- Strategic responses, positioning and initiatives
Where it runs
Any AI assistant that can read a Skill file, including Claude Code and Codex. Download the free plaintext package from Finch, install it with your assistant’s Skill method, or ask the assistant to read SKILL.md.
No extra API key, script or service. You still need access to an assistant model, which may carry its own subscription or usage cost. The Skill does not browse the web by itself; supply fresh market facts or use an assistant with search tools.
Limits and licence
Ratings are qualitative judgments, only as good as the facts supplied. The assistant may use in-between ratings such as Medium-High. Check every claim before acting on it.
MIT licence. Copyright (c) 2026 Pawel Huryn. Source: phuryn/pm-skills, commit 2a12295a7717, path pm-product-strategy/skills/porters-five-forces. The package adds a README, NOTICE, provenance note and a promotional cover; the instructions are unchanged.
How it was checked
One controlled Claude Code run on a fictional company produced all 12 parts the instructions require, labelled 8 unknowns and assumptions instead of inventing data, and gave a clear attractiveness verdict. Two forces used an intermediate Medium-High rating. The package downloaded back from Finch matched the audited files byte for byte. Native installation in each assistant and real business outcomes were not tested. The Benchmark tab has the full evidence trail.