sns-events

sns-events is a cursor rule for Cursor from GoranErhartic/cursor-development-rules. It costs 29 tokens per session (411 once invoked), scanned A, original, MIT.

A set of patterns for publishing events through Amazon SNS, a cloud messaging service that distributes one message to multiple subscribers, and processing them with AWS Lambda and SQS.

In plain words
What is it for?
Use it when building SNS topics, SQS subscriptions, Lambda event handlers, CDK infrastructure, FIFO messaging, or event-driven AWS systems.
Why use it?
It provides a consistent message format and rules for filtering, validation, duplicate processing, and request tracing. This helps prevent unreliable communication between cloud services.

Cursor rule for Cursor

Install

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.

agentmods
npx agentmods add rules/goranerhartic/cursor-development-rules/sns-events
Clone the repo
git clone --depth 1 https://github.com/GoranErhartic/cursor-development-rules

Made for: Cursor.

Wrote 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.

agentmods badge for sns-events

README.md
[![agentmods](https://agentmods.dev/badge/rules/goranerhartic/cursor-development-rules/sns-events.svg)](https://agentmods.dev/rules/goranerhartic/cursor-development-rules/sns-events)
Your own site
<a href="https://agentmods.dev/rules/goranerhartic/cursor-development-rules/sns-events"><img src="https://agentmods.dev/badge/rules/goranerhartic/cursor-development-rules/sns-events.svg" alt="Measured on agentmods" height="20"></a>
Per session 29 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 411 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00029 $0.00411
Opus 5 $0.00015 $0.00205
Sonnet 5 $0.00006 $0.00082
Haiku 4.5 $0.00003 $0.00041

Measured 3d ago against content hash 7f9161de5281, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

sns-events 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 3d 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.

.cursor/rules/languages/aws-lambda/sns-events.mdc · 37 lines

What it actually says

SNS Event Publishing Patterns

Event Envelope

  • Use consistent envelope: eventId, eventType, aggregateId, aggregateType, version, timestamp, correlationId, causationId?, metadata: { source, userId?, traceId? }, payload
  • Generate eventId (e.g. UUID); propagate correlationId from context or create new

Publishing

  • Client: @aws-sdk/client-sns; PublishCommand with TopicArn, Message (JSON string), MessageAttributes for filtering (e.g. eventType as String)
  • Message: Stringify envelope; set MessageGroupId for FIFO topics
  • Attributes: Use for SQS subscription filter policies; type String/Number/Binary

Receiving (SNS → Lambda)

  • Event: SNSEvent; event.Records[].Sns.Message is stringified payload; parse JSON; validate; process
  • Idempotency: Required when processing can be duplicated; use idempotency key from eventId or aggregateId+eventType

CDK

  • Create topic with new sns.Topic(); subscribe queue with topic.addSubscription(new subscriptions.SqsSubscription(queue)); filter policy on subscription for attribute-based filtering
  • FIFO: Topic and queue must be FIFO; MessageGroupId required

Conventions

  • Always use envelope; include correlationId; use message attributes for filtering; idempotent processing; log publish/consume with correlationId

Anti-Patterns

  • Raw payload without envelope; no correlationId; no idempotency for consumers; publishing without error handling

See also: sqs-processing.mdc, eventbridge.mdc, idempotency.mdc

Changes

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.

  1. 3d ago First seen · 37 lines · 29 tokens per session scan A 7f9161de5281

Subscribe to this mod's changes

sns-events is a cursor rule published in the GitHub repository GoranErhartic/cursor-development-rules (19 stars, last pushed 6mo ago), licensed MIT. It adds 29 tokens to every session and 411 once invoked, about $0.0001 per session on Opus 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.