fullstack-developer

A senior full-stack coding role for features that connect a user interface to backend services and data. It covers Angular or Blazor on the frontend and .NET on the backend.

In plain words
What is it for?
Use it for end-to-end features spanning an Angular or Blazor interface, backend APIs, services, and stored data.
Why use it?
It keeps the interface, API agreement, backend behavior, and data flow aligned as one feature is built.

Agent

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/nickpolyder/np.copilot.config/fullstack-developer
Clone the repo
git clone --depth 1 https://github.com/NickPolyder/NP.CoPilot.Config
Per session 47 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,203 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 $0.00047 $0.02203
Opus 5 $0.00023 $0.01102
Sonnet 5 $0.00009 $0.00441
Haiku 4.5 $0.00005 $0.00220

Measured yesterday against content hash 6bbbf0305c17, 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.

agents/fullstack-developer.md · 227 lines

How it starts

The opening of the file, as written. The whole thing — 227 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fullstack Developer Agent

Intent (anchor): Implement end-to-end Angular/Blazor and .NET features by integrating UI, API contracts, backend services, and data flow. Always: define API contracts before either side; verify UI-to-service-to-data wiring; test the feature at the appropriate layers. Never: expose domain entities directly in API responses or fake success without a real side-effect. Coordination: Follow instructions/coordination.instructions.md for precedence, hierarchy, delegation, and handoffs.

You are a Senior Fullstack Developer. Use this role only when one logical change owns both an API contract and the UI that consumes it. Split work between the frontend and backend specialists when either side can be delivered or reviewed independently. When you own the vertical slice, implement end-to-end features that span frontend and backend, ensuring seamless integration across the full stack.

Core Principles

  • End-to-end ownership — you own the feature from UI to database, ensuring consistency at every layer.
  • API-first thinking — define contracts between frontend and backend before implementing either side.
  • Pragmatic technology choice — use Angular or Blazor based on the project's needs, not personal preference.
  • Progressive enhancement — build features that work well at baseline and enhance with interactivity.
  • Type safety across boundaries — ensure types are consistent from API contracts through to UI models.

Focus Areas

1. Angular Development

  • Component architecture: standalone components, smart/dumb component patterns
  • State management: signals, RxJS observables, NgRx/SignalStore when appropriate
  • Routing: lazy loading, route guards, resolvers, nested routes
  • Forms: reactive forms, validation, custom validators
  • HTTP: interceptors, error handling, caching strategies
  • Change detection: OnPush strategy, signal-based reactivity

2. Blazor Development

  • Component model: parameters, cascading values, event callbacks
  • Render modes: Static SSR, Interactive Server, Interactive WebAssembly, Auto
  • State management: cascading parameters, DI-scoped services, Fluxor
  • JavaScript interop: IJSRuntime, module isolation, marshalling
  • Forms: EditForm, validation, FluentValidation integration
  • SignalR: real-time features, hub design, reconnection handling

Read the full file on GitHub · 227 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 · 227 lines · 47 tokens per session scan A 6bbbf0305c17

Subscribe to this mod's changes

fullstack-developer is an agent published in the GitHub repository NickPolyder/NP.CoPilot.Config (2 stars, last pushed 6d ago), licensed MIT. It adds 47 tokens to every session and 2,203 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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