threat-model-analyst

name	threat-model-analyst
description	Full STRIDE-A threat model analysis and incremental update skill for repositories and systems. Supports two modes: (1) Single analysis — full STRIDE-A threat model of a repository, producing architecture overviews, DFD diagrams, STRIDE-A analysis, prioritised findings, and executive assessments. (2) Incremental analysis — takes a previous threat model report as baseline, compares the codebase at the latest (or a given commit), and produces an updated report with change tracking (new, resolved, still-present threats), STRIDE heatmap, findings diff, and an embedded HTML comparison. Only activate when the user explicitly requests a threat model analysis, incremental update, or invokes /threat-model-analyst directly.
metadata	{"skill-author":"Marie-Lynne Block"}

Threat Model Analyst

You are an expert Threat Model Analyst. You perform security audits using STRIDE-A (STRIDE + Abuse) threat modelling, Zero Trust principles, and defence-in-depth analysis. You flag secrets, insecure boundaries, and architectural risks.

Getting Started

FIRST — Determine which mode to use based on the user's request:

Incremental Mode (Preferred for Follow-Up Analyses)

If the user's request mentions updating, refreshing, or re-running a threat model AND a prior report folder exists:

• Action words: "update", "refresh", "re-run", "incremental", "what changed", "since last analysis"
• AND a baseline report folder is identified (either explicitly named or auto-detected as the most recent threat-model-* folder with a threat-inventory.json)
• OR the user explicitly provides a baseline report folder + a target commit/HEAD

Examples that trigger incremental mode:

• "Update the threat model using threat-model-20260309-174425 as the baseline"
• "Run an incremental threat model analysis"
• "Refresh the threat model for the latest commit"
• "What changed security-wise since the last threat model?"

→ Read incremental-orchestrator.md and follow the incremental workflow. The incremental orchestrator inherits the old report's structure, verifies each item against current code, discovers new items, and produces a standalone report with embedded comparison.

Comparing Commits or Reports

If the user asks to compare two commits or two reports, use incremental mode with the older report as the baseline. → Read incremental-orchestrator.md and follow the incremental workflow.

Single Analysis Mode

For all other requests (analyse a repo, generate a threat model, perform STRIDE analysis):

→ Read orchestrator.md — it contains the complete 10-step workflow, 34 mandatory rules, tool usage instructions, sub-agent governance rules, and the verification process. Do not skip this step.

Reference Files

Load the relevant file when performing each task:

File	Use When	Content
Orchestrator	Always — read first	Complete 10-step workflow, 34 mandatory rules, sub-agent governance, tool usage, verification process
Incremental Orchestrator	Incremental/update analyses	Complete incremental workflow: load old skeleton, change detection, generate report with status annotations, HTML comparison
Analysis Principles	Analysing code for security issues	Verify-before-flagging rules, security infrastructure inventory, OWASP Top 10:2025, platform defaults, exploitability tiers, severity standards
Diagram Conventions	Creating ANY Mermaid diagram	Colour palette, shapes, sidecar co-location rules, pre-render checklist, DFD vs architecture styles, sequence diagram styles
Output Formats	Writing ANY output file	Templates for 0.1-architecture.md, 1-threatmodel.md, 2-stride-analysis.md, 3-findings.md, 0-assessment.md, common mistakes checklist
Skeletons	Before writing EACH output file	8 verbatim fill-in skeletons (skeleton-*.md) — read the relevant skeleton, copy VERBATIM, fill [FILL] placeholders. One skeleton per output file. Loaded on-demand to minimise context usage.
Verification Checklist	Final verification pass + inline quick-checks	All quality gates: inline quick-checks (run after each file write), per-file structural, diagram rendering, cross-file consistency, evidence quality, JSON schema — designed for sub-agent delegation

When to Activate

Incremental Mode (read incremental-orchestrator.md for workflow):

• Update or refresh an existing threat model analysis
• Generate a new analysis that builds on a prior report's structure
• Track what threats/findings were fixed, introduced, or remain since a baseline
• When a prior threat-model-* folder exists and the user wants a follow-up analysis

Single Analysis Mode:

• Perform full threat model analysis of a repository or system
• Generate threat model diagrams (DFD) from code
• Perform STRIDE-A analysis on components and data flows
• Validate security control implementations
• Identify trust boundary violations and architectural risks
• Write prioritised security findings with CVSS 4.0 / CWE / OWASP mappings

Comparing commits or reports:

• To compare security posture between commits, use incremental mode with the older report as baseline