Amazon Q in IDE: Customizations That Respect CODEOWNERS Boundaries

Amazon Q customizations are only as safe as the corpus you feed them. If you dump the entire monorepo into one customization, payments idioms leak into marketing suggestions and vice versa — and CODEOWNERS becomes theater. Scope customizations the way you scope IAM roles: by ownership boundary.

⚡ TL;DR: Build one Q customization (or context pack) per CODEOWNERS domain. Index only paths that team owns. Tag suggestions with the customization ID in telemetry. Refuse to answer cross-boundary questions without an explicit @other-team allow. Pair with Amazon Q Developer: Custom Context Packs and Cursor Rules for AWS CDK.

Parse CODEOWNERS into corpus allowlists

// codeowners-to-corpus.ts
export type Domain = { name: string; owners: string[]; globs: string[] };

export function domainsFromCodeowners(text: string): Domain[] {
  const map = new Map<string, Domain>();
  for (const line of text.split("\n")) {
    const t = line.trim();
    if (!t || t.startsWith("#")) continue;
    const [glob, ...owners] = t.split(/\s+/);
    const key = owners.sort().join(",");
    const d = map.get(key) ?? { name: key, owners, globs: [] };
    d.globs.push(glob);
    map.set(key, d);
  }
  return [...map.values()];
}

export function filterPathsForDomain(paths: string[], domain: Domain, match: (p: string, g: string) => boolean) {
  // ✅ Only files owned by this domain enter the customization job
  return paths.filter((p) => domain.globs.some((g) => match(p, g)));
}

# Example domains
# CODEOWNERS
/packages/payments/**  @acme/payments
/packages/marketing/** @acme/growth
/infra/cdk/**          @acme/platform

❌ One customization job with s3://corp-monorepo/full-mirror/.
✅ Three jobs: q-payments, q-growth, q-platform.

Bind the IDE profile to the active package

// ide-plugin — select customization from cwd / git path
export function selectCustomization(filePath: string, domains: Domain[]): string {
  const d = domains.find((x) => x.globs.some((g) => minimatch(filePath, g)));
  if (!d) return process.env.Q_DEFAULT_CUSTOMIZATION!; // generic, no sensitive corpora
  return `q-${slug(d.owners[0])}`;
}

When an engineer opens packages/payments/src/ledger.ts, Q must not retrieve marketing React patterns. Context packs from Amazon Q Developer: Custom Context Packs should carry the same ownership stamps.

Training and retrieval both need boundaries

Metadata filters mirror Bedrock Retrieval Filters — ownership is just another tenant axis inside the company.

Telemetry without leaking code

{
  "customizationId": "q-payments",
  "ownerTeam": "payments",
  "accepted": false,
  "suggestionKind": "completion",
  "pathPrefix": "packages/payments/"
}

Never log raw suggestion text to shared analytics. Cost attribution still applies — LLM Cost Controls.

Closing checklist

• [ ] CODEOWNERS parsed into domain corpora; no full-monorepo customization
• [ ] IDE selects customization from active file path
• [ ] Retrieval metadata includes ownerTeam; cross-team requires explicit allow
• [ ] Eval harness includes cross-domain leakage tests
• [ ] Telemetry stores customization ID, not suggestion bodies
• [ ] Platform/infra customization excludes product PII paths

Related reading

• Amazon Q Developer: Custom Context Packs for Private Monorepos
• Bedrock Retrieval Filters: Tenant Isolation for Multi-SaaS Code RAG
• Cursor Rules for AWS CDK: Stop AI From Inventing IAM Wildcards
• Claude Projects vs Cursor: Context Hygiene for Regulated Codebases

Last updated on September 11, 2026