Purpose

Deliver an actionable AppSec-grade threat model specific to a repository or project path — not a generic checklist. Anchor every architectural claim to repo evidence, keep assumptions explicit, and prioritize realistic attacker goals over boilerplate.

Operating procedure

1. Collect inputs

• Repo root path and any in-scope paths.
• Intended usage, deployment model, internet exposure, and auth expectations (if known).
• Any existing repository summary or architecture spec.
• Use prompts in

  references/prompt-template.md

  to generate a repository summary.
• Follow the required output contract in

  references/prompt-template.md

  . Use it verbatim when possible.

2. Scope and extract the system model

• Identify primary components, data stores, and external integrations from the repo summary.
• Identify how the system runs (server, CLI, library, worker) and its entrypoints.
• Separate runtime behavior from CI/build/dev tooling and from tests/examples.
• Map in-scope locations to components; explicitly exclude out-of-scope items.
• Do not claim components, flows, or controls without evidence.

3. Derive boundaries, assets, and entry points

• Enumerate trust boundaries as concrete edges between components (protocol, auth, encryption, validation, rate limiting).
• List assets that drive risk (data, credentials, models, config, compute, audit logs).
• Identify entry points (endpoints, upload surfaces, parsers, job triggers, admin tooling, logging sinks).

4. Calibrate attacker capabilities

• Describe realistic attacker capabilities based on exposure and intended usage.
• Explicitly note non-capabilities to avoid inflated severity.

5. Enumerate threats as abuse paths

• Map attacker goals to assets and boundaries (exfiltration, privilege escalation, integrity compromise, DoS).
• Classify each threat and tie to impacted assets.
• Keep threats small in number but high in quality.

6. Prioritize with likelihood × impact

• Use qualitative likelihood and impact (low/medium/high) with short justifications.
• Set overall priority (critical/high/medium/low), adjusted for existing controls.
• State which assumptions most influence the ranking.

7. Validate with user

• Summarize key assumptions that affect threat ranking or scope.
• Ask 1–3 targeted questions to resolve missing context (deployment model, authn/authz, data sensitivity, multi-tenancy).
• Pause for feedback. If user declines, state which assumptions remain and how they influence priority.

8. Recommend mitigations

• Distinguish existing mitigations (with evidence) from recommended ones.
• Tie mitigations to concrete locations and control types (authZ checks, input validation, schema enforcement, sandboxing, rate limits, secrets isolation, audit logging).
• Prefer specific implementation hints over generic advice.

9. Quality check before finalizing

• Confirm all discovered entrypoints are covered.
• Confirm each trust boundary is represented in threats.
• Confirm runtime vs CI/dev separation.
• Confirm user clarifications are reflected.
• Confirm format matches

  references/prompt-template.md

  .
• Write final Markdown to

  <repo-or-dir-name>-threat-model.md

  .

Risk prioritization guidance

• High: pre-auth RCE, auth bypass, cross-tenant access, sensitive data exfiltration, key/token theft, model/config integrity compromise, sandbox escape.
• Medium: targeted DoS of critical components, partial data exposure, rate-limit bypass with measurable impact, log poisoning affecting detection.
• Low: low-sensitivity info leaks, noisy DoS with easy mitigation, issues requiring unlikely preconditions.

Output defaults

Threat model written to

<repo-or-dir-name>-threat-model.md

following the contract in

references/prompt-template.md

. Includes: system model, trust boundaries, asset inventory, threat table (ID, category, likelihood, impact, priority), mitigations (existing + recommended), assumptions, and open questions.

References

• Output contract and prompt template:

  references/prompt-template.md

• Optional controls/asset list:

  references/security-controls-and-assets.md

• https://owasp.org/www-community/Threat_Modeling
• https://cheatsheetseries.owasp.org/

Only load reference files you need. Keep the final result concise, grounded, and reviewable.

Failure handling

• User won't answer validation questions: State which assumptions remain unresolved, mark affected recommendations as conditional, and proceed with explicit caveats.
• Repo too large to fully analyze: Focus on declared entrypoints and sensitive paths (auth, crypto, API boundaries). State which areas were not analyzed.
• No clear trust boundaries: Report that the architecture lacks explicit boundaries — this is itself a finding. Recommend boundary definition as first mitigation.
• Conflicting architecture signals: Flag contradictions (e.g., code says microservices, deploy says monolith) and ask user to clarify before finalizing.