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Security Threat Model · majiayu000 | DecimalAI

securityby majiayu000

Security Threat Model

majiayu000/security-threat-model

Source majiayu000/spellbook ↗License MIT

Threat-model product features, APIs, data flows, secrets, permissions, supply-chain changes, auth boundaries, and risky code paths before or during implementation.

NewMaintained

Automatic

Security & AppSec pack

Last verified 8/27/2026

What it changes

Passed 10 of 22 test cases with the skill, and 12 of 22 without it.

Without skill55%

With skill45%

Checks it passed that the model alone missed

The assets section identifies secret tokens.
The assets section identifies money movement.
The trust boundaries section identifies tenant boundaries.

and 2 more in the full report

3 fixed7 passed either way8 still failing4 broke

Pass-rate lift: -9 pp
Tokens: +6%
Agent turns: 0%
Response time: -5%

Model gemini-3.6-flashMeasured 8/27/2026v110 of 22 cases passed with skill

Tokens, turns and time describe resource use, not a dollar price.

Use this skill

Save it into your project's skills folder. Claude Code picks it up in its next session.

curl -fsSL --create-dirs -o .claude/skills/majiayu000-security-threat-model/SKILL.md https://app.decimal.ai/s/majiayu000-security-threat-model/SKILL.md

Want it pinned and updatable? pip install "decimalai>=0.15", then decimalai skills add majiayu000-security-threat-model, and start Claude Code with claude --plugin-dir "$(git rev-parse --show-toplevel)/.agents"

1 · One-time — install the CLI (docs ↗)

pip install "decimalai>=0.15"

2 · Get the skill — writes .agents/skills/majiayu000-security-threat-model/ and pins it in .decimal/skills.lock

decimalai skills add majiayu000-security-threat-model

No CLI? Get the same file — curl · raw file

curl -fsSL --create-dirs -o .claude/skills/majiayu000-security-threat-model/SKILL.md https://app.decimal.ai/s/majiayu000-security-threat-model/SKILL.md

Raw file: /s/majiayu000-security-threat-model/SKILL.md ↗ · machine-readable summary at /s/majiayu000-security-threat-model.json ↗

Safety checks: 3 of 3 passed

Code scan CleanIntent PassedContent Clean

See it in action

One of 3 test cases the skill fixed. Same model, same prompt, with and without the skill.

1 of 3

Prompt

We are introducing a shared database table schema for multi-tenant account records. Perform a threat analysis on tenant data isolation during query execution, accounting for accidental cross-tenant data leaks.

What was checked, without and with the skill
Checked	Without skill	With skill
The threats section evaluates information disclosure.	Passed	Passed
The trust boundaries section identifies tenant boundaries.	Missed	Passed

case-08 · gemini-3.6-flash · 8/27/2026 · answers are capped and redacted

What's inside

The instructions your model reads when the skill loads.

SKILL.md54 linessingle file

Security Threat Model

Purpose

Use this skill before implementing or approving security-sensitive changes. It complements auth-security and server-security by mapping assets, attackers, trust boundaries, and concrete controls.

Scope First

Identify:

Assets: credentials, tokens, user data, tenant data, money movement, admin actions.
Actors: anonymous user, authenticated user, tenant admin, internal operator, compromised dependency.
Trust boundaries: browser/server, service/service, tenant/tenant, CI/runtime, third-party callbacks.
Entry points: API routes, CLI commands, jobs, webhooks, uploads, config files.
Existing controls: validation, authz, rate limits, audit logs, secret storage.

Threat Checklist

Check at least:

Spoofing: can an identity, tenant, callback, or service be forged?
Tampering: can payloads, configs, migrations, artifacts, or logs be altered?
Repudiation: is there an audit trail for sensitive actions?
Information disclosure: can secrets, PII, logs, or tenant data leak?
Denial of service: can expensive paths be amplified?
Elevation of privilege: can user or service permissions expand?
Supply chain: can dependencies, scripts, CI, or generated files introduce risk?

Required Controls

Every finding needs one of:

preventive control in production code,
detective control with alerting,
compensating manual control with owner and expiry,
explicit accepted risk with rationale.

Do not accept "warn and continue" for authz, secrets, tenant isolation, injection, or payment/security-critical failures.

Output Shape

Track record

Benchmark

10 / 22

test cases passed, vs 12 / 22 without

Adoption

Users: 0
Times used: 0

Safety and source details

SkillSafety

✓ 3 of 3 passed

Code scan15 of 15 checks clean

0 critical · 0 warning · 0 info — scanner v4 — 8/3/2026

View 15 scanner checks

live_secretremote_code_executionreverse_shelldata_exfiltrationssrf_metadataagent_snoopinganti_refusaldestructive_commandsobfuscated_unicodeunicode_homoglyphopaque_blobsuspicious_urltool_overreachtrigger_abuseprompt_injection_phrasing

IntentSafe

LLM judge · does the skill do what it claims

ContentClean

LLM judge · policy & harmful-content review

Source

Imported

majiayu000 / spellbook

skills/security-threat-model/SKILL.md

View on GitHub ↗

License MITImported 8/3/2026Version v1

Other skills for the same job

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More skills from the same source and nearby in the registry, with their headline benchmark lift.

Ready to supercharge your AI agents?

See it in action

What's inside

Security Threat Model

Purpose

Scope First

Threat Checklist

Required Controls

Output Shape

Track record

Benchmark

Adoption

SkillSafety

Source

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