Create Threat Model

Overview

Generate a STRIDE-based threat model (Microsoft) for a system or component. Identifies trust boundaries from architecture docs, analyzes each boundary for Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, and Elevation of Privilege threats, and recommends mitigations for each identified threat.

Workflow

1. Read architecture context -- Scan .chalk/docs/engineering/ for architecture docs, API designs, data models, and infrastructure descriptions. Check .chalk/docs/product/ for PRDs that describe the feature's intended behavior. You need to understand the system before modeling threats against it.

2. Parse the target system -- Extract from $ARGUMENTS the system, service, or component to threat model. If unspecified, ask the user to name the scope -- threat modeling the entire system at once is too broad to be useful.

3. Determine the next file number -- Read filenames in .chalk/docs/engineering/ to find the highest numbered file. The next number is highest + 1.

4. Identify trust boundaries -- Map the boundaries where data or control crosses between different trust levels: client/server, service/service, internal/external, user/admin, authenticated/unauthenticated. Each boundary is a potential attack surface.

5. Apply STRIDE at each boundary -- For each trust boundary, analyze:

   • Spoofing: Can an attacker impersonate a legitimate entity?
   • Tampering: Can data be modified in transit or at rest?