Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
git clone --depth 1 https://github.com/GoranErhartic/cursor-development-rulesWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/rules/goranerhartic/cursor-development-rules/security)<a href="https://agentmods.dev/rules/goranerhartic/cursor-development-rules/security"><img src="https://agentmods.dev/badge/rules/goranerhartic/cursor-development-rules/security/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/rules/goranerhartic/cursor-development-rules/security"><img src="https://agentmods.dev/badge/rules/goranerhartic/cursor-development-rules/security.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00035 | $0.00469 |
| Opus 5.5 | $0.00014 | $0.00188 |
| Sonnet 5.5 | $0.00007 | $0.00094 |
| Haiku 4.5 | $0.00003 | $0.00047 |
Grade A, and why
security scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
Lambda Security Patterns
IAM Least Privilege
- CDK: Grant only required actions on specific resources:
table.grantReadWriteData(role),queue.grantConsumeMessages(role),topic.grantPublish(role); avoid*on resources when possible - Basics: Lambda execution role needs
logs:CreateLogGroup,logs:CreateLogStream,logs:PutLogEvents; X-Ray:xray:PutTraceSegments,xray:PutTelemetryRecords - Secrets: Grant
secretsmanager:GetSecretValueonly for specific secret ARNs used by the function - SSM: Grant
ssm:GetParameter*for parameter paths the function reads
Secrets
- Never in code or env as plain text in CDK; use Powertools Parameters (
getSecret,getParameter) with SSM/Secrets Manager; cache with short TTL - Store DB URLs, API keys in Secrets Manager; reference by ARN in CDK and pass to function as env (e.g.
SECRET_ARN); function fetches value at runtime
Network
- VPC: Only when Lambda must access private RDS/VPC resources; add to private subnets; consider NAT for outbound if needed; cold start impact
- API Gateway: Use WAF for rate limiting, IP rules, bot protection; restrict CORS to known origins in HTTP API config
CORS
- Configure CORS on HTTP API (allow-origin, allow-methods, allow-headers); do not use
*in production for credentials
Conventions
- Least privilege IAM; secrets via Parameters/Secrets Manager; validate input at boundaries; HTTPS only; CORS and WAF on API
Anti-Patterns
- Broad IAM (
*on resources); secrets in env or code; missing CORS or overly permissive; no input validation
See also: powertools-parameters.mdc, api-gateway-http-api.mdc, ../../patterns/security.mdc
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 37 lines · 35 tokens per session scan A 3fafbef8a42b
security is a cursor rule published in the GitHub repository GoranErhartic/cursor-development-rules (19 stars, last pushed 7mo ago), licensed MIT. It adds 35 tokens to every session and 469 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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