# Build brief — a focused alternative to Claude

> **Verdict:** Not faithfully · **Buildability:** 21/100 · **Category:** AI Assistant
> **Source:** https://www.canitbevibecoded.com/claude
> Independent editorial assessment from Can It Be Vibe Coded? Not affiliated with, endorsed by, or derived from Claude. Verify current pricing and capabilities before acting.

## Context

**Claude** — AI assistant for writing, reasoning, coding, and document work. It currently costs $20/mo.

A Claude-like UI is trivial; the model, safety/reliability layer, long-context performance, artifacts/projects, and platform distribution are not.

This brief describes a focused, single-operator replacement for the part of Claude that is genuinely reproducible. It is deliberately narrower than the product it replaces, and it says so in writing. Build the useful core; do not pretend to have rebuilt the rest.

## What you are building

Build a chat app using Anthropic API, with document upload, conversation storage, and optional project contexts.

- Build a focused single-user workflow with real persistence, search, and export.
- A responsive interface with real empty, loading, success, and error states.

## Requirements

### Functional

- Hosted app.
- File parsing.
- Storage.
- Optional vector search.

### Data and integrations

- Anthropic API key.

Each of these needs a real account, credential, or quota. Set them up before writing feature code.

### Non-functional

- Accessibility: semantic markup, labelled controls, visible focus, and reduced-motion support.
- Security: server-side secrets, validated input, and no credentials in the client bundle.
- Reliability: retries with backoff on external calls, and a clear failure state when a provider is down.
- Portability: the operator can export their data and leave without losing it.

## Implementation brief

Build me a personal chat client on the Anthropic API to replace my Claude Pro
subscription with per-token billing. Requirements:

- A local web app: Node + Express + better-sqlite3, streaming replies over SSE,
  a conversation sidebar, Markdown rendering with marked.
- Anthropic API key in .env; model picker with Sonnet as the default and Opus
  on demand; system prompt editable and saved per project.
- Projects: a project groups conversations and holds a few reference docs
  (plain text or PDF via pdf-parse) prepended as context for every chat inside
  it.
- Use prompt caching on the project docs to cut token costs, the API supports
  it directly.
- SQLite FTS5 search across all conversations; export any thread to Markdown.
- A cost meter per conversation plus a monthly total from the API usage fields,
  so the keep-paying-or-not decision is a number, not a feeling.
- Localhost only, no accounts, no telemetry.
- Out of scope: artifacts, mobile apps, and agent features. If the cost meter
  shows heavy use, flat-rate Pro or Max wins; include that comparison logic in
  the README.
- README: key setup, a link to current per-token prices, and state that the
  model is the product; this wrapper only changes how I pay for it.

## Delivery standard

- Inspect the repository first, then write a short implementation plan before writing code.
- Deliver the smallest complete end-to-end workflow first; every primary control must work against persisted data.
- Use real validation and storage; never substitute fake dashboards, decorative controls, hard-coded success states, or mock integrations.
- Include responsive layouts plus genuine empty, loading, success, validation, and failure states.
- Keep secrets server-side in environment variables, provide .env.example, and never commit credentials or user data.
- Add structured logs around every external call and return actionable errors without leaking sensitive details.
- Write unit tests for the core logic and one automated test of the main user journey.
- Finish with a README covering setup, architecture, data location, backups, tests, deployment, and known limitations.

## Acceptance criteria

- [ ] A clean install starts the app using only the README and .env.example.
- [ ] The primary journey works from first visit through saved result, reload, edit, export, and deletion where applicable.
- [ ] Invalid input, missing configuration, provider failure, and an empty database each have a usable state.
- [ ] The interface works at 390px and 1440px, is keyboard navigable, and shows visible focus on every control.
- [ ] Tests, type checking, linting, and a production build all pass with no ignored failures.
- [ ] No part of the interface implies a live integration, security guarantee, or scale capability that was not actually built and verified.

## Non-goals

Do not build these, and do not claim to have replaced them:

- Frontier model.
- Long-context quality.
- Product surface.
- Mobile apps.
- Model quality and inference operations are part of the product.
- Reliability at the vendor's scale is an operations problem, not a prompt.

## What you still own after launch

- Secure credentials, rotate secrets, and handle provider rate limits.
- Run migrations, backups, restores, and dependency updates.
- Test the critical journey after every model, API, or hosting change.
- Monitor failures and fix the edge cases a first prompt will miss.

## Risk

**Operational risk.** The code is achievable; dependable data, integrations, and ongoing operations are the real cost.

Editorial confidence in this assessment: high. No independent one-shot implementation is linked yet.

## Prior art

Working open-source software you can read, fork, or borrow from before starting:

- [LibreChat](https://github.com/danny-avila/LibreChat) — Open-source multi-model AI chat platform for self-hosting API-based assistants

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