Porters Five Forces Agent Skill

Porter's Five Forces (Evidence-Cited)

Purpose

Read an industry's structure through Porter's Five Forces, with evidence: **search plan →

force-by-force ratings with signals → profit-pool implication → next-step options.** Each force —

competitive rivalry, threat of new entrants, threat of substitutes, buyer power, supplier power — is

rated weak/moderate/strong and justified with documented signals, because a rating without signals is

vibes. The analysis closes where it should have been aiming all along: **where the profit pool sits

and who is squeezing it.** Five forces is an argument about where margin goes, not a diagram for

slide four.

Input

Works best with: the industry or segment, named as precisely as you can ("clinical data

management SaaS," not "healthcare"), and the decision this analysis should support.

Also useful: a geographic boundary if the structure differs by region, and a

market-landscape-scan in session — the forces read builds on

it and searches only gaps.

Input supplied inline with the invocation — text after the skill name, a pasted context dump, or an

appended ARGUMENTS: line — counts as answers already given. Use it against the question budget;

don't re-ask.

Arriving empty-handed? That works too. The skill opens with at most 3 questions (segment,

decision, boundary) and proceeds on labeled assumptions if they go unanswered.

Example invocation: `Five forces on mid-market field-service management software, North America —

decision: whether we enter or partner.`

Key Concepts

• Governing protocol: honors the autonomous-investigation

contract — question budget of 3, search-plan gate, Fact/Inference/Assumption labels, Just Enough

Mode (2-4 signals per force), stable schema, 4-option Final Step. Disciplines: FININT

(concentration, margins, filings) + OSINT (analyst coverage, trade press) per

intelligence-collection-disciplines.

• The framework (Porter, 1979): industry profitability is determined by five structural forces,

not by how hard incumbents work. Rivalry sets the intensity of margin competition; entry threat

caps pricing; substitutes cap value; buyer power extracts margin downstream; supplier power

extracts it upstream. Structure explains what negotiation skill cannot: **pricing power is

structural.**

• Ratings must survive "how do you know?" Each weak/moderate/strong rating stands on documented

signals — concentration data, switching costs, entry examples and how they fared, substitute

adoption curves, margin trends. Forces-with-signals is the difference between naming a framework

and using one.

• AI-driven substitution is a named candidate, always. In most knowledge industries it is now

*the* substitute threat; assess it explicitly in the substitutes force rather than letting the

analysis pretend it's 2015. Supplier power gets the same modern read: cloud, model, and platform

dependencies are supplier concentration.

• Industry, not player: this reads what the structure does to *everyone* who plays.

swot-analysis reads one company's position within it.

• When NOT to use: nascent categories with no stable structure — the forces are still forming;

run the landscape scan and revisit.

• Do-not-invent list: market share, margin data, entrant names, funding rounds, adoption figures.

Application

• Credit inline context, then ask only the unanswered questions (max 3):
• Which industry or segment, precisely?
• What decision should this support?
• Any geographic boundary?
• Show the 3-bullet search plan — what you'll search per force, source types (filings, analyst

coverage, trade press, pricing pages, funding databases), fact/inference separation. Continue

unless revised. If a landscape scan is in session, build on it; search only gaps.

• Rate each force with signals, then emit the schema below exactly.

Output schema (do not reorder)

~~~markdown

Five Forces: [Industry / Segment]

As-of date: | Boundary: | Decision supported:

1. Competitive Rivalry — [weak / moderate / strong]

• Signals: [concentration, growth rate, differentiation, exit barriers — each with URL + label]
• What it means here: [one sentence]

2. Threat of New Entrants — [weak / moderate / strong]

• Signals: [entry barriers, capital needs, recent entrants and how they fared, regulation — each with URL + label]
• What it means here: [one sentence]

3. Threat of Substitutes — [weak / moderate / strong]

• Signals: [substitute adoption, price-performance trajectory, switching evidence — each with URL + label]
• AI-driven substitution, named and assessed: [labeled]
• What it means here: [one sentence]

4. Buyer Power — [weak / moderate / strong]

• Signals: [buyer concentration, switching costs, price transparency, backward-integration examples — URL + label]
• What it means here: [one sentence]

5. Supplier Power — [weak / moderate / strong]

• Signals: [supplier concentration (including cloud/model/platform dependencies), input differentiation — URL + label]
• What it means here: [one sentence]

6. The Profit Pool (the "so what")

• Where margin sits today, and the force squeezing it: [labeled]
• Structure trend: [tightening / loosening, on what evidence]
• For your decision: [2 sentences tying structure to the decision named above]

Assumptions to Validate

• [Assumption 1] / [Assumption 2] / [Assumption 3]

~~~

A copy/paste fill-in version of this schema, with quality checks, lives in template.md.

Final Step (offer exactly 4 options)

• Trace the strongest force into your strategy's exposed assumptions
• Run market-landscape-scan to name the players behind each force
• Feed the profit-pool read into an Ansoff growth-options analysis (ansoff-matrix)
• Schedule-ready version: which force signals should a re-run watch?

Accept 1, 2, 3, 4, 1 and 3, Verbose Mode, or a custom path.

Examples

A rating that survives "how do you know?" (fictional):

> ## 4. Buyer Power — strong

> - Signals: top 10 buyers account for ~60% of segment spend — Fact ([trade association data,

> URL]); three publicized incumbent-to-rival switches in 18 months with no reported penalty —

> Fact ([press coverage, URLs]); public rate cards make pricing fully transparent — Fact

> ([vendor pricing pages]); one major buyer built the capability in-house — Fact ([their

> engineering blog, URL])

> - What it means here: buyers can credibly threaten to leave or build, so list-price integrity is

> an illusion in this segment — discounting pressure is structural, not a sales-discipline problem.

The profit-pool close doing its job: rivalry moderate, entrants weak, substitutes strong (AI

agents absorbing the low-complexity tier), buyers strong, suppliers moderate. The pool sits in the

regulated high-complexity tier — the only place two strong forces don't reach — Inference. For

the entry decision: enter *only* via the regulated tier; the volume tier's margin is already spoken

for by buyers below and AI substitution above.

See examples/sample.md for a complete worked five-forces read (fictional

FSM-software market) that builds on the market-landscape-scan example and lands at a profit-pool

close that changes the decision. examples/sample-industrial.md

shows the forces inverting in an industrial market — read both to see the framework adapt instead

of recite.

Common Pitfalls

• Ratings as vibes. "Rivalry: strong" because it feels crowded. Every rating stands on signals

with URLs, or the whole exercise is a diagram.

• Skipping the AI substitute. Assessing substitutes as adjacent products while an AI workflow

eats the category's low end. Name it and rate it, even when the rating is "weak — for now."

• Confusing competitors with structure. Listing who plays (that's the landscape scan) instead of

what the structure does to everyone who plays. The forces are about margin physics, not rosters.

• No profit-pool close. Five rated forces and no answer to "where does margin go?" The close is

the analysis; everything above it is evidence assembly.

• Forcing structure onto a nascent category. Rating forces that haven't formed yet produces

confident noise. Say "still forming," scan the landscape, revisit in two quarters.

References

• autonomous-investigation (Workflow) — the governing protocol
• intelligence-collection-disciplines (Component) — FININT/OSINT sources behind the signals
• market-landscape-scan (Workflow) — who plays; this skill asks what the structure does to them
• swot-analysis (Workflow) — one company's position within the structure
• ansoff-matrix (Workflow) — growth options informed by the profit-pool read
• Michael E. Porter, "How Competitive Forces Shape Strategy" (Harvard Business Review, 1979)
• Adapted from market-intelligence/porters-five-forces-prompt.md in the

https://github.com/deanpeters/product-manager-prompts repo.