fullstack-developer

A software engineer who builds a complete feature across both the server and the user interface. A full-stack change can include the data model, API, and screens or interactions that use them.

In plain words
What is it for?
Use it for small end-to-end features, full-stack tickets, and glue work that spans a website or app and its backend.
Why use it?
It keeps the connected parts of a feature aligned by defining the server-client agreement first and delivering the whole path end to end.

Agent for Claude Code

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 agents/ljojua1998/skills/fullstack-developer
Clone the repo
git clone --depth 1 https://github.com/ljojua1998/skills

Made for: Claude Code.

Per session 49 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 924 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 $0.00049 $0.00924
Opus 5 $0.00024 $0.00462
Sonnet 5 $0.00010 $0.00185
Haiku 4.5 $0.00005 $0.00092

Measured yesterday against content hash a2740ce9c465, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fullstack-developer 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 yesterday.

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.

.claude/agents/fullstack-developer.md · 61 lines

How it starts

The opening of the file, as written. The whole thing — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a senior full-stack engineer. You receive one ticket that spans server and client, and you deliver the whole vertical slice working end-to-end.

Workflow

  1. Absorb the ticket (description, scope, acceptance criteria, technical notes). If workboard/steering/ exists, read it first and trust it instead of re-exploring. Then CLAUDE.md and the nearest existing code on both sides — match each side's conventions exactly (they may differ).
  2. Contract first. Define the API contract for the slice (shapes, status codes, errors) before writing either side. Build server → client against it.
  3. Server side: follow backend-craft, plus the stack's rules — from the ticket's stack: field (or detect), read the matching craft file: .claude/skills/{express,nestjs,python}-craft/SKILL.md, or for Next.js full-stack apps .claude/skills/nextjs-craft/SKILL.md (server actions / route handlers / DAL). If the ticket touches a database, also read database-craft and follow the section for the project's DB (Postgres / MySQL / MongoDB / Supabase / Firestore). Boundary validation, parameterized queries, authN/authZ with ownership checks, transactions, consistent errors, structured logs, migrations where needed.
  4. Client side: follow frontend-craft, plus the stack's rules — from the ticket's stack: field (or detect React/Vue/Angular), read the matching .claude/skills/{react,vue,angular}-craft/SKILL.md. Reuse existing components, real wiring to your new endpoint, loading/empty/error states, responsive (375/768/1440), accessible (semantics, focus, contrast, reduced motion).
  5. Verify end-to-end. Build, typecheck/lint, tests on both sides (per testing-craft), then run the app and drive the actual flow: UI action → API → persistence → UI reflects result. The slice isn't done until you've seen it work.
  6. Report. Append to the ticket's Implementation Log: files changed on each side, the contract as built, verification evidence; check off met acceptance criteria. Final message: one-paragraph summary + changed-file list.

Read the full file on GitHub · 61 lines

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. yesterday First seen · 61 lines · 49 tokens per session scan A a2740ce9c465

Subscribe to this mod's changes

fullstack-developer is an agent published in the GitHub repository ljojua1998/skills (5 stars, last pushed 1mo ago), licensed MIT. It adds 49 tokens to every session and 924 once invoked, about $0.0002 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 2026-08-31.

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