stamp-base

name: stamp-base description: Use when any STAMP-related analysis is needed. Provides theoretical foundations and routes to appropriate methodology (STPA for prospective, CAST for retrospective, STPA-Sec for security).

STAMP Foundations

Overview

STAMP (Systems-Theoretic Accident Model and Processes) reframes safety: accidents emerge from inadequate control of system behavior, not from chains of component failures. Instead of asking "what broke?", ask "what constraints were missing or inadequate?"

This base skill provides:

• Theoretical foundations for all STAMP analysis
• Routing to the appropriate methodology skill
• Shared concepts used across STPA, CAST, and STPA-Sec

Routing

digraph routing {
    rankdir=TB;

    entry [label="Safety/failure\nconcern raised" shape=ellipse];
    timing [label="Has loss already\noccurred?" shape=diamond];
    security [label="Adversarial\nthreat?" shape=diamond];

    cast [label="Use stamp-cast\n(retrospective)" shape=box style=filled fillcolor=lightgray];
    stpa [label="Use stamp-stpa\n(prospective)" shape=box style=filled fillcolor=lightgreen];
    stpasec [label="Use stamp-stpa-sec\n(security)" shape=box style=filled fillcolor=lightblue];

    entry -> timing;
    timing -> cast [label="yes"];
    timing -> security [label="no"];
    security -> stpasec [label="yes"];
    security -> stpa [label="no"];
}

When ambiguous: Ask one question:

"Are we analyzing something that already happened, or preventing something that might happen?"

The Paradigm Shift

If you're new to STAMP, here's what this methodology does:

If you're familiar with fault trees, event chains: STAMP flips the question. Instead of "what failed?" (component fault tree), we ask "what constraints prevented the hazard?" (control structure analysis). This captures how systems migrate toward danger over time.

If you're familiar with systems thinking, control loops: STAMP formalizes your intuition. Every system has controllers (human and automated), controlled processes, feedback, and control actions. Accidents happen when control is inadequate.

If you're designing something new: Use stamp-stpa to identify hazards BEFORE they become problems by analyzing what could go wrong with your control structure.

If you're investigating an incident: Use stamp-cast instead. This analyzes what already happened and why the control structure failed.

Core Concepts

See references/stamp-foundations.md for:

• Accidents as emergent properties
• The control structure model
• Four conditions for safe control
• Causation categories
• Why "human error" is the wrong terminus
• Migration to hazard

Training & Onboarding

For users new to STAMP, see references/training-intro.md:

• Mapping STAMP to familiar concepts (fault trees, control loops)
• Quick paths for different user contexts (safety, incident response, compliance)
• Handling resistance and common objections

Quick Reference

Four conditions for safe control:

1. Goals align with safety (not just production)
2. Control actions available (authority + means)
3. Process model accurate (controller understands reality)
4. Feedback adequate (timely, accurate information)

Output Formats

STAMP analysis serves different audiences. See references/output-formats.md for:

• Executive Summary — Decision-focused, business impact
• Engineering Specification — Actionable requirements with traceability
• Incident Report — Compliance-ready, methodology-documented
• Quick Brief — Verbal settings, alignment conversations

Combined Workflows

For systems with both safety and security concerns, skills can be chained:

• STPA → STPA-Sec: Run STPA first for safety hazards, then STPA-Sec to add adversarial scenarios to the same control structure
• STPA-Sec → STPA: Start with security threats, then extend to full safety analysis
• CAST → STPA / STPA-Sec: After incident analysis, run prospective analysis on the redesigned control structure

The control structure model is shared across all three methodologies—each builds on rather than duplicates the others.

Related Skills

• stamp-stpa — Prospective hazard analysis (what could go wrong?)
• stamp-cast — Retrospective incident analysis (what went wrong?)
• stamp-stpa-sec — Security-focused analysis (adversarial scenarios)