docs(destination-gcs-data-lake): Update setup guidance

[devin-ai-integration]

Triggering Context

Run triggered by: API request using the !connectordocs playbook for merged connector commit 35b6138.

Relevant context: #78235

Confidence impact: The scope was clear because the triggering commit was a merged CDK/version bump for one connector, so the Triggering Context score is high.

Documentation Confidence Assessment

Overall Confidence: 2/5 capped: too much code inference

Dimension	Score	Rationale
Code Comprehension	1/5	This is a Java/Kotlin destination connector, so the confidence gate caps the score even though the relevant spec and catalog code were readable.
API Documentation Quality	4/5	Google Cloud, Apache Polaris, and Apache Iceberg publish official docs covering the auth, catalog, and storage concepts used here.
Change Scope & Risk	3/5	The diff makes moderate additions to prerequisites, setup guidance, field coverage, examples, and changelog dates.
Existing Doc Maturity	4/5	The existing 235-line document already covered prerequisites, setup, configuration, sync modes, schema behavior, deduplication, branching, and compaction.
Connector Sensitivity	3/5	The connector is certified with ql: 300 and sl: 300, so it warrants reviewer caution.
Triggering Context	5/5	The task was triggered from a small merged PR with a clear connector and version bump scope.

What I Verified vs. What I Inferred

• Verified from code: The connector is Java/Kotlin; supports BigLake and Polaris catalogs; requires service account JSON, GCP location, warehouse location, catalog type, and catalog-specific fields; supports overwrite, append, append+dedup, and incremental; exposes optional gcs_endpoint; uses GCSFileIO; Polaris test setup grants table and namespace privileges needed for writes.
• Verified from API docs: BigLake uses an Iceberg REST catalog for Cloud Storage-backed tables; BigLake catalog writers use BigLake and Cloud Storage IAM permissions; Service Usage Consumer includes serviceusage.services.use; Polaris principals use OAuth client credentials and catalog privileges such as CATALOG_MANAGE_CONTENT; Iceberg supports branch semantics and equality deletes.
• Inferred: The exact minimum production IAM set may vary by organization and catalog mode, so the PR distinguishes administrator setup permissions from Airbyte runtime permissions rather than documenting every possible Google Cloud policy combination.

Areas of Concern

• Please review the BigLake IAM guidance carefully. I matched it to the connector's runtime behavior and Google Cloud docs, but Google Cloud deployments can require organization-specific roles or custom IAM policies.
• Because this is a Java/Kotlin connector, the confidence gate requires substantive human review despite the narrow docs scope.

---

What

Update the GCS Data Lake destination documentation after #78235 and the broader connector docs review.

How

• Correct the BigLake/GCS service account role guidance to document BigLake Editor, Storage Object User, and Service Usage Consumer instead of unrelated BigQuery roles.
• Clarify that BigLake is an Iceberg REST catalog service, that billing and the BigLake API must be enabled, and that catalog administration may require broader roles than the Airbyte runtime service account.
• Add the optional GCS Endpoint field to the configuration table.
• Add programmatic BigLake and Polaris JSON examples for PyAirbyte, Terraform, or API users.
• Correct recent changelog dates for merged PRs chore: bump to latest cdk. #78235, chore: bump cdk fix coercer injection. #76406, and chore(destination-gcs-data-lake): update to latest CDK #72855.

Review guide

1. Review the service account and BigLake setup guidance for permission accuracy.
2. Review the new reference examples and confirm the field names match the connector spec.
3. Review the changelog date corrections against the linked merged PRs.

User Impact

Users get more accurate setup instructions for BigLake and GCS permissions, plus field-name examples for configuring the connector programmatically.

Verification

• Docs / MarkDownLint passed in CI.
• Docs / Vale passed in CI.
• Build Airbyte Docs passed in CI.
• cd docusaurus && corepack pnpm@9.4.0 install --frozen-lockfile && corepack pnpm@9.4.0 clear && corepack pnpm@9.4.0 build completed locally.
• Preview rendered at https://airbyte-docs-kurchoiu3-airbyte-growth.vercel.app/integrations/destinations/gcs-data-lake.

Note: The optional GitHub Actions Vercel Preview job failed after creating the preview because the Vercel API request ended with read ECONNRESET. The deployment URL above is reachable, and the separate Vercel – airbyte-docs status passed.

Can this PR be safely reverted and rolled back?

• YES
• NO

---

Note: I am an AI assistant (Devin) and have proposed these documentation updates based on a review of the connector source code and third-party API documentation. Reviewers may merge, modify, or close this PR as they see fit.

---

Devin session

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment and CI monitoring

[github-actions]

👋 Greetings, Airbyte Team Member!

Here are some helpful tips and reminders for your convenience.

💡 Show Tips and Tricks

PR Slash Commands

Airbyte Maintainers (that's you!) can execute the following slash commands on your PR:

• 🛠️ Quick Fixes
  • /format-fix - Fixes most formatting issues.
  • /bump-version - Bumps connector versions, scraping changelog description from the PR title.
    • Bump types: patch (default), minor, major, major_rc, rc, promote.
    • The rc type is a smart default: applies minor_rc if stable, or bumps the RC number if already RC.
    • The promote type strips the RC suffix to finalize a release.
    • Example: /bump-version type=rc or /bump-version type=minor
  • /bump-progressive-rollout-version - Alias for /bump-version type=rc. Bumps with an RC suffix and enables progressive rollout.
• ❇️ AI Testing and Review (internal link: AI-SDLC Docs):
  • /ai-prove-fix - Runs prerelease readiness checks, including testing against customer connections.
  • /ai-canary-prerelease - Rolls out prerelease to 5-10 connections for canary testing.
  • /ai-review - AI-powered PR review for connector safety and quality gates.
• 📝 AI Documentation:
  • /ai-docs-review - AI-powered documentation review for PRs with connector changes.
  • /ai-create-docs-pr - Creates a documentation PR for connector changes, stacked on the current PR.
• 🚀 Connector Releases:
  • /publish-connectors-prerelease - Publishes pre-release connector builds (tagged as {version}-preview.{git-sha}) for all modified connectors in the PR.
• ☕️ JVM connectors:
  • /update-connector-cdk-version connector=<CONNECTOR_NAME> - Updates the specified connector to the latest CDK version.
    Example: /update-connector-cdk-version connector=destination-bigquery
• 🐍 Python connectors:
  • /poe connector source-example lock - Run the Poe lock task on the source-example connector, committing the results back to the branch.
  • /poe source example lock - Alias for /poe connector source-example lock.
  • /poe source example use-cdk-branch my/branch - Pin the source-example CDK reference to the branch name specified.
  • /poe source example use-cdk-latest - Update the source-example CDK dependency to the latest available version.
• ⚙️ Admin commands:
  • /force-merge reason="<REASON>" - Force merges the PR using admin privileges, bypassing CI checks. Requires a reason.
    Example: /force-merge reason="CI is flaky, tests pass locally"

📚 Show Repo Guidance

Helpful Resources

• Breaking Changes Guide - Breaking changes, migration guides, and upgrade deadlines
• Developing Connectors Locally
• Managing Connector Secrets
• On-Demand Regression Tests
• #connector-ci-issues
• #connector-publish-updates
• #connector-build-statuses

📝 Edit this welcome message.