Spec Driven Development
MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.
Description from the maker (original English)
Give your AI agent the ability to respond with live, interactive apps that evolve.
These three are never merged into one score: opinions, measurements and popularity are different things.
We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.
Pick the AI app you use, then copy the settings.
SAC_API_KEY, SAC_API_BASE, SAC_MODEL, SAC_SEARCH_API_KEYValues marked secret are keys to your account. Never share them or paste them into a chat.
You need
Which app do you use?
Pick your app above. We remember it, so next time the button says “Install in …”.
Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json
{
"mcpServers": {
"sac": {
"command": "uvx",
"args": [
"sac-sdk"
],
"env": {
"SAC_API_KEY": "your-value",
"SAC_API_BASE": "your-value",
"SAC_MODEL": "your-value",
"SAC_SEARCH_API_KEY": "your-value"
}
}
}
}Run this in your terminal
claude mcp add sac --env SAC_API_KEY=your-value --env SAC_API_BASE=your-value --env SAC_MODEL=your-value --env SAC_SEARCH_API_KEY=your-value -- uvx sac-sdkFill in the empty values before running it.
Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json
{
"mcpServers": {
"sac": {
"command": "uvx",
"args": [
"sac-sdk"
],
"env": {
"SAC_API_KEY": "your-value",
"SAC_API_BASE": "your-value",
"SAC_MODEL": "your-value",
"SAC_SEARCH_API_KEY": "your-value"
}
}
}
}Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.
Paste into .vscode/mcp.json in your project
{
"servers": {
"sac": {
"type": "stdio",
"command": "uvx",
"args": [
"sac-sdk"
],
"env": {
"SAC_API_KEY": "your-value",
"SAC_API_BASE": "your-value",
"SAC_MODEL": "your-value",
"SAC_SEARCH_API_KEY": "your-value"
}
}
}
}Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.
This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.
Your choice stays on this device in a cookie; no account needed.
SAC_API_BASE envSAC_MODEL envThese settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.
Runs on your computer; the tool list appears in your AI app after you install it.
We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 6, 2026
The publisher (dynsoft.ai) is not the repo owner (Software-As-Content); someone else may have listed it
We have not read this repo from GitHub yet
We have not read this repo from GitHub yet
This one runs on your computer; there is no internet endpoint
Runs on your computer and uses local settings instead
Runs on your computer; we can only read tool lists from internet endpoints
Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.
It passed 0 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.
You need to fill in: SAC_API_KEY, SAC_SEARCH_API_KEY
It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).
The GitHub repo last changed –, and the latest version (0.1.2) reached the registry 6 months ago.
Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Python (uv) on your computer.
In the same category: Spec Driven Development, Remote Desktop Commander, Intervals MCP
Servers in the same category from other makers, sorted by stars.
Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi
MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.
Remote Desktop Commander: use files, terminal and processes on your own computers from any AI app.
Remote MCP server for intervals.icu run data and analysis
Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.
AI agents can reason, code, and call APIs — but when they need to communicate back to you, all they have is text. SaC (Software as Content) is the missing interaction layer: your agent responds with a live, persistent, interactive app that evolves as the conversation continues. Not a screenshot, not a markdown wall — a real UI you click, explore, and shape together with your agent.
pip install sac-sdk
sac serve
First time? It'll ask for your API key and save it. Then open http://localhost:18420, type *"3-day Tokyo trip planner with budget"*, and watch a live React app stream in. Click buttons. Ask it to evolve. This is SaC running a built-in agent loop — no external agent needed.
SaC plugs into the agent you already use — through MCP, Skill, or code.
pip install sac-sdk
sac setup claude-code # registers SaC as an MCP server
Restart Claude Code. Then try:
*"Help me understand this codebase using a visualized and interactive app using SaC MCP."*
Setup details →
pip install sac-sdk
sac setup codex # installs the SaC skill sac serve # keep running in a terminal
Setup details →
pip install sac-sdk
sac setup openclaw # installs the SaC skill sac serve # keep running in a terminal
Setup details →
from sac import SaC
sac = SaC() conv = sac.conversation() app = await conv.generate("3-day Tokyo itinerary") print(app.url) # user opens this
Your agent ──▶ SaC ──▶ User sees a live app at a URL
◀── User clicks a button / types a message Your agent ──▶ SaC ──▶ Same URL, app evolves in place ◀── ...
One URL, one conversation. The agent doesn't generate a new page every turn — it evolves the existing app. Users keep their context; the agent keeps its state.
Two channels, one loop: every response is either a UI update (the app evolves) or a chat reply (a text bubble). Users can click buttons in the app OR type in the chat — both go back to the agent through the same callback.
SaC is for tasks where exploration and interaction matter more than a final answer.
Good fit: trip planning, data analysis dashboards, comparison shopping, project planning, research, financial reviews, decision aids, internal tools
Not the right tool for: simple Q&A, one-shot automations ("set an alarm"), conversations that are purely text
Every layer is pluggable:
from sac import SaC, FileStore
sac = SaC( llm=YourLLMProvider(...), # any class implementing LLMProvider search=YourSearchProvider(...), # any class implementing SearchProvider store=FileStore(".sac"), )
Prompts live in src/sac/runtime/prompts/ and the default design system is in src/sac/renderer/design-systems/default/.
src/sac/
├── sac.py / conversation.py Entry + Conversation primitive ├── runtime/ Generate + Evolve pipeline, prompts, providers ├── server/ │ ├── http/ FastAPI + SSE streaming + viewer │ └── mcp/ MCP stdio server (Claude Code integration) └── renderer/ iframe sandbox + design system
Full architecture →
v0.1.2 — alpha. The core protocol (generate → evolve → callback loop) is stable and runs in production at sac.dynsoft.ai. The SDK surface is being polished toward v1.0.
Issues and PRs welcome. Highest-leverage contributions right now:
src/sac/runtime/prompts/src/sac/renderer/design-systems/For local dev: pip install -e .
Apache-2.0