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Context Assembler

Context Assembler

Combine files and folders into one LLM-ready context block — like repomix or files-to-prompt, fully in your browser

    Add files

    Folder uploads preserve the directory tree. node_modules, .git, dist and build output are skipped automatically and never read.

    Limits: up to 500 files, 1.0 MB each, 20.0 MB total. Heavier picks are reported, not lost.

    Comma or newline separated. Names match any path segment; * is a glob.

    Large language models like Claude and ChatGPT give much better answers when you hand them complete, well-structured context — but copy-pasting files one by one is tedious and you constantly forget a file. The Context Assembler is the browser-based counterpart of CLI tools such as repomix and files-to-prompt: pick a whole folder (structure preserved) or add individual files, and it merges everything into a single text block an LLM can read. Each file is wrapped in <file path="...">…</file> tags so the model always knows which file it is looking at, with an optional ASCII project tree up top. Heavy directories (node_modules, .git, dist, build, .next) are skipped automatically and never read, and you can fine-tune with your own ignore patterns or limit to specific extensions (.ts, .tsx). A live token estimate (≈4 characters per token) tells you how much of the context window you are using, with a link to the Token Cost Calculator to turn that into dollars. Binary files are detected and skipped, and everything runs locally in your browser — your code is never uploaded.

    Examples

    Assemble a TypeScript project

    📁 Pick folder: my-app/

<file path="my-app/src/index.ts">
import { greet } from "./utils";
greet("world");
</file>
<file path="my-app/src/utils.ts">
export const greet = (n: string) => console.log(`Hello, ${n}!`);
</file>
<file path="my-app/package.json">
{ "name": "my-app", "type": "module" }
</file>

    Each file is wrapped in an XML tag with its relative path. The optional tree header gives the model a map of the project first.

    Filter to one extension

    Extensions: .ts,.tsx
Ignore: node_modules, *.test.ts, dist

→ Only non-test TypeScript files are included.

    Combine an extension allow-list with ignore globs to ship just the source files that matter for a code-review prompt.

    Right-size the context window

    Output: 12,480 chars · ≈3,120 tokens
→ Open Token Cost Calculator

    The token estimate shows how much of the context window the assembly uses before you paste it.

    About this tool

    Merge files and folders into one LLM context block with XML tags, a project tree and a token estimate. Free and client-side — like repomix / files-to-prompt. No uploads. Context Assembler runs in the browser on DevTools. There is no signup, and your input stays on this device unless the tool explicitly performs a live network lookup.

    What this tool does not do

    • Context Assembler is a free in-browser utility, not a hosted API. It does not keep server-side history and is not a substitute for production verification in your own stack.

    How do I use this tool?

    1. How do I use Context Assembler?

      Open Context Assembler, enter or paste your input, and copy the result. The page works without an account.

    Related guides

    LLM Context Assembly and Prompt Template Engineering

    How to assemble structured context windows for LLMs, manage token budgets, format system instructions, and design prompt templates.

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