# Transcript: Threat Model of build-agents-md.js and validate-skill.js

## Task Understanding

Run a threat model on two Node.js build/validation scripts (`build-agents-md.js` and `validate-skill.js`) used as internal dev tooling for the dot-skills project. These scripts read skill directories and check their structure. The goal is a quick security check confirming they are not doing anything dangerous. Output a THREAT-MODEL.md to the specified outputs directory.

## Steps Taken

### Step 1: Read the primary scripts

**Why:** Need to understand the full source code to identify security-relevant operations (file I/O, network calls, shell execution, deserialization, user input handling).

**Tools used:** Read tool

**Files read:**
- `/Users/pedroproenca/.claude/plugins/marketplaces/dot-claude/plugins/dev-skill/scripts/build-agents-md.js` (232 lines)
- `/Users/pedroproenca/.claude/plugins/marketplaces/dot-claude/plugins/dev-skill/scripts/validate-skill.js` (412 lines)

**Findings:** Both scripts use `fs` and `path` only. `build-agents-md.js` reads skill directories and writes a compiled AGENTS.md. `validate-skill.js` reads skill directories, runs validation checks, and prints reports to stdout. `validate-skill.js` imports from `./validation/validator.js` and `./build-agents-md.js`.

### Step 2: Identify all transitive dependencies

**Why:** The validator imports a module tree. Need to read all files in the dependency graph to identify any hidden dangerous operations.

**Tools used:** Glob tool, then Bash (cat) for reading

**Files discovered and read:**
- `/Users/pedroproenca/.claude/plugins/marketplaces/dot-claude/plugins/dev-skill/scripts/validation/validator.js` (~735 lines)
- `/Users/pedroproenca/.claude/plugins/marketplaces/dot-claude/plugins/dev-skill/scripts/validation/schemas.js` (~712 lines)
- `/Users/pedroproenca/.claude/plugins/marketplaces/dot-claude/plugins/dev-skill/scripts/validation/constants.js` (~389 lines)
- `/Users/pedroproenca/.claude/plugins/marketplaces/dot-claude/plugins/dev-skill/scripts/validation/types.js` (~57 lines)
- `/Users/pedroproenca/.claude/plugins/marketplaces/dot-claude/plugins/dev-skill/scripts/validation/markdown-parser.js` (~96 lines)

**Findings:** The full dependency tree uses `fs`, `path`, `unified`, `remark-parse`, `remark-frontmatter`, `unist-util-visit`, and `yaml`. No networking, no child_process, no eval/Function, no dynamic require.

### Step 3: Analyze each threat category

**Why:** Systematic review against standard threat categories (STRIDE-lite approach adapted for CLI tooling).

**Tools used:** Analysis of read source code (no additional tool calls needed)

**Categories checked:**
1. **Path traversal** -- CLI arg used as directory path, no boundary validation, acceptable for internal tool
2. **File writes** -- Single write in build-agents-md.js (hardcoded filename AGENTS.md), content derived from directory contents
3. **JSON/YAML deserialization** -- JSON.parse (safe), yaml package (safe defaults, no code execution)
4. **ReDoS** -- Reviewed ~50+ regex patterns; no nested quantifiers or catastrophic backtracking patterns found
5. **Prototype pollution** -- Manual frontmatter parser uses `{}` with direct key assignment; theoretical but no exploit path
6. **Command injection** -- Not present; no shell execution anywhere
7. **Network access** -- Not present; no networking modules imported
8. **Environment variables** -- Single env var (SKILL_VALIDATOR_CONCURRENCY), integer-parsed and validated
9. **Supply chain** -- 5 well-known npm packages (unified ecosystem + yaml); standard risk

### Step 4: Write the threat model output

**Why:** Produce the deliverable as requested.

**Tools used:** Write tool

**Output file:** `/Users/pedroproenca/Documents/Projects/dot-skills/skills/.experimental/threat-model-workspace/iteration-1/eval-3-harness-scripts-low-surface/without_skill/run-1/outputs/THREAT-MODEL.md`

## Issues Encountered

- The Read tool's caching returned "File unchanged since last read" for validator.js and schemas.js even though their contents had not been displayed in the conversation. Resolved by using the Bash tool with `cat -n` to force-read the file contents.

## Output Produced

- **THREAT-MODEL.md** -- Full threat model document with 10 threat entries, attack surface summary, findings table, verdict, and defense-in-depth recommendations. Located at: `/Users/pedroproenca/Documents/Projects/dot-skills/skills/.experimental/threat-model-workspace/iteration-1/eval-3-harness-scripts-low-surface/without_skill/run-1/outputs/THREAT-MODEL.md`

## Verdict

The scripts are safe for internal use. No dangerous operations found. No network access, no shell execution, no dynamic code evaluation. The attack surface is minimal: local file reads, one intentional file write (AGENTS.md), and CLI argument parsing. Three minor defense-in-depth suggestions were provided (prototype pollution guard, concurrency cap, dependency auditing), none of which represent actual vulnerabilities in the current context.
