FPF — First Principles Framework

What is FPF?

The First Principles Framework (FPF) is an “Operating System for Thought” — a transdisciplinary architecture for reasoning. It turns raw intelligence (human or machine) into organisationally usable reasoning.

FPF is built into Forgeplan via the /fpf command and the forgeplan fpf CLI.

Three Reasoning Modes

/fpf decompose — Break it down

When you have a complex system and need to understand its parts.

/fpf decompose our authentication system

Output:

Table: Context | Responsibility | Key Roles | Interfaces
Mermaid diagram with boundaries and connections
Category error check (role vs function?)

When to use: Starting a new feature, understanding existing system, planning architecture.

/fpf evaluate — Compare options

When you need to choose between alternatives with evidence scoring.

/fpf evaluate React vs Vue vs Svelte for our SPA

Output:

Strengths, weaknesses, evidence, missing evidence per option
F-G-R scores: Formality (0-3), Granularity (0-3), Reliability (0-3)
Decision matrix with recommendation
ADI cycle: hypotheses → predictions → evidence check

When to use: Technology selection, architecture decisions, trade-off analysis.

/fpf reason — Think it through

When you need to understand why something happened or how to approach a problem.

/fpf reason why our API response times degraded

Output:

Abduction: 3+ hypotheses
Deduction: Testable predictions per hypothesis
Induction: Check against available evidence
Scored hypotheses: supported / weakened / refuted
Conclusion with remaining uncertainties

When to use: Debugging, incident response, problem analysis, architecture justification.

FPF Knowledge Base

Forgeplan includes the full FPF specification as a searchable knowledge base:

# Ingest FPF spec sections
forgeplan fpf ingest

# Search for concepts
forgeplan fpf search "bounded context"

# Use FPF context in reasoning
forgeplan reason PRD-001 --fpf

Key FPF Concepts

Concept	What it means
Bounded Context	A part of the system with clear boundaries and its own vocabulary
Trust Calculus	Scoring confidence: how much can you trust a claim?
F-G-R	Formality × Granularity × Reliability — quality dimensions
ADI Cycle	Abduction → Deduction → Induction — structured reasoning loop
Category Error	Confusing role vs function, method vs work
Gamma Algebra	How parts compose into wholes preserving properties

Installation

# As Claude Code plugin
npx skills add ForgePlan/marketplace --plugin fpf

# Or use built-in CLI
forgeplan fpf search "trust"

See the Marketplace Overview for the full plugin catalog and install instructions.