--- name: aws-sst-development description: SST v4 (Ion) expert for managing AWS resources as code with the Pulumi-backed framework. Use when writing or editing sst.config.ts, building infra/ modules (sst.aws.Function/Bucket/Dynamo/Cron/Service/Router, sst.Secret, sst.Linkable, raw aws.* Pulumi resources), wiring resource links,... risk: unknown source: https://github.com/zxkane/aws-skills/tree/main/plugins/aws-iac/skills/aws-sst-development source_repo: zxkane/aws-skills source_type: community date_added: 2026-07-01 license: MIT license_source: https://github.com/zxkane/aws-skills/blob/main/LICENSE --- # SST v4 for AWS ## When to Use Use this skill when you need sST v4 (Ion) expert for managing AWS resources as code with the Pulumi-backed framework. Use when writing or editing sst.config.ts, building infra/ modules (sst.aws.Function/Bucket/Dynamo/Cron/Service/Router, sst.Secret, sst.Linkable, raw aws.* Pulumi resources), wiring resource links,... SST v4 (the "Ion" engine) is a Pulumi-backed IaC framework: you describe AWS resources in TypeScript and SST/Pulumi reconciles them into your account. It gives you high-level `sst.aws.*` components (Function, Bucket, Dynamo, Cron, Service, …) that expand into many underlying resources, plus an escape hatch to *any* raw Pulumi `aws.*` resource for the long tail. This skill encodes a production-proven way to author, link, test, deploy, and troubleshoot SST stacks on AWS — distilled from real multi-stack projects that have paid for each lesson with a prod incident. **SST and Pulumi are third-party — verify current syntax with Context7** (`resolve-library-id` → `query-docs` for `sst` or `pulumi-aws`) when you're unsure about a component's options. Verify AWS-side facts (service limits, model IDs, IAM action names, region availability) with the AWS docs MCP, never from memory. The patterns here are the *how*; the docs are the *what*. ## When you're invoked Figure out which mode you're in and jump to the right reference: | Situation | Go to | |-----------|-------| | New project, or adding a resource/module to an existing SST app | **Author** → `references/authoring.md` | | Wiring one module's output into another (links, SSM, IAM scope) | **Author** → `references/authoring.md` § Sharing | | Writing tests for infra so changes don't silently break | **Test** → `references/testing.md` | | Running a deploy, or a deploy just failed | **Deploy/Operate** → `references/deploy-and-troubleshoot.md` | | Migrating a resource between Pulumi types, renaming a physical name | **Deploy/Operate** → `references/deploy-and-troubleshoot.md` § Migrations | Always read the relevant reference before editing — they carry the *why* behind each rule, which matters more than the rule itself. ## Orientation: read the repo before you touch it SST projects are conventional but not identical. Before editing, build a quick map so your change matches the house style instead of fighting it: 1. **`sst.config.ts`** — the app name, `home`, providers/region, `defaultTags`, any global `$transform` (Node runtime pin, bundle fixups), and the order in which `run()` imports `infra/` modules. The import order *is* the dependency order; respect it. 2. **`infra/`** — one file per domain (storage, functions, api, observability…). This is where resources are declared. Check for an `infra/CLAUDE.md` — these projects keep IaC-specific rules there, and it's the single most valuable file to read first. 3. **`infra/tests/`** — source-level Vitest assertions that pin resource invariants. If they exist, your change must keep them green and probably needs a new assertion. 4. **`package.json` / `.nvmrc`** — package manager (npm vs pnpm), Node version, and the `sst`/`pulumi` versions actually installed. Run `npx sst version` to confirm you're on v4/Ion (the `$config` + `.sst/platform/` signature). v2/v3 ("SST Classic", CDK-based) is a different framework — these patterns don't apply there. ## The conventions, and which are universal vs tunable The projects this skill is built from share a deliberate house style. Some of it is **universal** (true for any SST v4 + AWS project — apply it everywhere); some is **project-specific** (a sensible default these projects chose — adopt it for consistency, but recognize a project may differ). **Universal — these principles hold for any SST v4 + AWS project:** - **Control the Node runtime deliberately, in one place.** Don't leave it to whatever the installed SST happens to default to. The idiom is a single global `$transform(sst.aws.Function, (args) => { args.runtime ??= "nodejs24.x" })` in `run()` — `??=` is correct here (the transform runs before the component applies its own default, so it fills in only when the user didn't set one). Recent SST already defaults to a current Node runtime, so check the installed default first (Context7); the transform is then version-independence insurance so a future SST downgrade can't silently move your fleet. See `references/authoring.md`. - **Never interpolate a Pulumi `Output` into a plain JS template literal.** Use `$interpolate` (or `pulumi.interpolate`). A bare top-level `` `${bucket.arn}/*` `` stringifies the `Output` to a `[Output]` placeholder and produces a broken ARN that only fails at deploy time (it type-checks and `sst dev` runs fine). The fix is `$interpolate`​`` `${bucket.arn}/*` ``. This has caused prod deploy outages. See `references/authoring.md` § Outputs. - **Migrating a resource between Pulumi *types* should default to two PRs** — Pulumi creates-before-destroys, so for a uniqueness-constrained AWS name (bucket, IAM role, gateway) the old resource still owns it and the create fails with `ConflictException`. Two sequential deploys (teardown, then recreate) is the conservative default; `aliases:` / `pulumi import` / state surgery can bridge identity in some cases but only with a reviewed plan. See `references/deploy-and-troubleshoot.md` § Migrations. - **Prefer typed `sst.aws.*` / `aws.*` resources over the `aws.cloudcontrol.Resource` escape hatch.** CloudControl outputs are stringly-typed and `oneOf` fields don't patch cleanly. Use it only when no typed resource exists yet, and migrate off it when one ships. **Project-specific defaults — adopt for consistency, but confirm per repo:** - **Region `ap-northeast-1`**, `home: "aws"`, and `defaultTags` carrying `Project` / `Stage` / `ManagedBy: "sst"`. - **Stage-gated lifecycle**: `removal: stage === "prod" ? "retain" : "remove"` and `protect: stage === "prod"` so prod resources survive a stack tear-down and non-prod previews clean up. - **SSM Parameter Store as the out-of-graph contract** under a `/{app}/{stage}/{domain}/...` prefix — for consumers that aren't in the Pulumi graph (CI scripts, sibling apps, operators). For *same-app* Lambdas, prefer SST `link:` (it wires a real dependency edge and grants IAM); don't route same-app sharing through SSM. See `references/authoring.md` § Sharing. - **Lazy `await import("./infra/")` inside `run()`** so `sst dev` hot-reload stays light. (For testing, a module export still runs its top-level `new sst.aws.*` unless it's wrapped in a factory function — see `references/testing.md` for how to test infra.) - **Source-level Vitest tests** on every infra module — a lightweight, house-style regression net asserting on the *source text* (resource names, index shapes, IAM scopes). It's a deliberate choice, not an SST limit: Pulumi *does* support runtime mocks (`@pulumi/pulumi/runtime`) for behavioral graph tests when a module has real logic. Source assertions don't replace a preview-deploy + smoke test. See `references/testing.md`. - **An observability gate**: every new Lambda/queue/schedule gets an alarm and structured logging before merge. Whether you enforce this depends on the project, but it's cheap insurance. See `references/deploy-and-troubleshoot.md` § Observability. When you introduce a convention, say which bucket it's in ("this is universal" vs "matching this repo's house style") so the user can override the project-specific ones deliberately. ## Working rhythm 1. **Orient** (above) — map config, modules, tests, tooling. 2. **Verify syntax** with Context7 / AWS docs MCP if anything is non-obvious. Don't guess at a component's option name. 3. **Author** the resource/module following `references/authoring.md`. Match the surrounding file's commenting density and naming — these projects comment the *why* heavily, and a terse one-liner in a heavily-annotated file reads as a regression. 4. **Test** — add or update source-level assertions (`references/testing.md`) and run `npx vitest` (or the repo's `test` script). Run `npx sst diff` and/or `tsc --noEmit` to catch type and plan errors before deploying. 5. **Deploy/operate** per `references/deploy-and-troubleshoot.md`. Confirm the target account with `aws sts get-caller-identity` before any `sst deploy`. 6. **Clean up** any exported state files — they contain account IDs and ARNs and must not linger in `/tmp` or chat history. ## What good looks like - The change is the smallest diff that satisfies the requirement, in the right `infra/` module, wired into `run()` in dependency order. - Every Lambda gets the right runtime via the global transform (you didn't hand-set `runtime` unless intentionally diverging — e.g. a Python function). - Cross-resource references use `link:` (in-graph) and/or `$interpolate`-scoped IAM; outputs other tools consume are published to SSM under the stage prefix. - New infra has a matching source-level test, and the existing suite stays green. - You confirmed AWS-side facts via the docs MCP and SST/Pulumi syntax via Context7 rather than relying on recall. - Anything irreversible (deploy, `sst remove`, a resource-type migration) was flagged to the user with the account it targets, and migrations were planned as two PRs, not one. ## Limitations - Use this skill only when the task clearly matches its upstream source and local project context. - Verify commands, generated code, dependencies, credentials, and external service behavior before applying changes. - Do not treat examples as a substitute for environment-specific tests, security review, or user approval for destructive or costly actions.