# One Person, Five Roles: Shipping a Full App with Claude Code on GCP

> A Google Cloud demo shows one person playing five roles to build and deploy a full feedback app using Claude Code with Claude models on Vertex AI.

Published: 2026-05-26
URL: https://daniliants.com/insights/he-spent-26-minutes-showing-exactly-what-one-person-with-claude/
Tags: claude-code, google-cloud, vertex-ai, mcp, subagents, devops, ci-cd

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## Summary

A Google Cloud developer advocate demos how one person, wearing five roles (PM, UI/UX, software engineer, security reviewer, analyst), builds and ships a full feedback app on Google Cloud using Claude Code with Claude models hosted on Vertex AI. The talk maps each Claude Code feature (plan mode, subagents, MCP, skills, plugins) to a stage of the software lifecycle and walks the app from paper sketch to production deploy plus analytics dashboard.

## Key Insight

**Claude-on-Vertex vs API key**

- Auth via Application Default Credentials plus a wizard that auto-detects project/region and lets you pin available Claude models. No API key to store or rotate.
- Billing is pay-per-token with no message cap; need more capacity, use Provisioned Throughput.
- Data stays in your GCP project; models served multi-region/global endpoints for HA.

**Feature-to-role mapping (the actual recipe)**

- PM role: CLAUDE.md rule turns a coffee-napkin sketch into a wireframe, auto-commits and opens a PR (PM never touches Git).
- UI/UX role: plan mode converts wireframe into 4 production pages; Claude proposes spec before coding (could pull from Figma).
- Engineer role: subagents parallelize, one for API, one for BigQuery pipeline, one for dashboard, simulating a team sprint with different models.
- Security role: custom plugin runs an input-validation plus service-account permission review, fixes code, re-tests, opens PR.

**Two new Google Cloud integrations worth noting**

- Developer Knowledge API plus MCP server: gives Claude fresh GCP docs/implementation guides refreshed every 24h, so it picks the right architecture (Cloud Run plus Filestore plus BigQuery plus Looker) without the dev knowing GCP.
- Official Google Cloud Skills: handle actual deploy, generating a Cloud Build (CI) plus Cloud Deploy (CD) pipeline that triggers on PR merge, with dev-to-prod promotion gating.
- BigQuery MCP plus a Looker/dashboard MCP turn raw feedback data into analytics and a shareable dashboard link on the fly.