Spec Driven Development
MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.
Description from the maker (original English)
Calibrated advice for coding agents: typed questions in, probabilities out. Apple Silicon.
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.
EMBER_SERVER_URL, EMBER_AUTH_TOKENValues 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": {
"ember": {
"command": "uvx",
"args": [
"ember-advise",
"mcp"
],
"env": {
"EMBER_SERVER_URL": "your-value",
"EMBER_AUTH_TOKEN": "your-value"
}
}
}
}Run this in your terminal
claude mcp add ember --env EMBER_SERVER_URL=your-value --env EMBER_AUTH_TOKEN=your-value -- uvx ember-advise mcpFill in the empty values before running it.
Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json
{
"mcpServers": {
"ember": {
"command": "uvx",
"args": [
"ember-advise",
"mcp"
],
"env": {
"EMBER_SERVER_URL": "your-value",
"EMBER_AUTH_TOKEN": "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": {
"ember": {
"type": "stdio",
"command": "uvx",
"args": [
"ember-advise",
"mcp"
],
"env": {
"EMBER_SERVER_URL": "your-value",
"EMBER_AUTH_TOKEN": "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.
EMBER_SERVER_URL 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 registry name was verified with the GitHub account shapeandshare, which owns the repo
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 1 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: EMBER_AUTH_TOKEN
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 (0.16.0) reached the registry 23 days 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, BankBridge
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.
Works in any MCP agent, including local models. Read-only bank accounts, spending, investments.
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.
A gut feeling for coding agents. AI coding assistants like Claude Code, Codex, opencode, and Kilo Code constantly have to decide: start now or ask a question first? Is this test failure real? Is this change safe to push? ember is a small add-on that gives them a quick second opinion at those moments, as a number ("93% likely this needs review"), so they stop interrupting you needlessly and stop making risky changes without asking. You don't call it yourself; your assistant does. It's free and open source, and you choose where the model runs: on your Apple Silicon Mac (32 GB of memory or more, a one-time ~18 GB download), on a server you host, or on one your team already runs. ember advises; the agent decides.
Under the hood, ember runs Cloudflare's Clef-Flash decision model, from its public Hugging Face repo, and exposes it as one MCP tool, advise, that returns a calibrated probability for every option.
Website: shapeandshare.github.io/ember
All three are supported equally; ember init asks which one you want.
| On your Mac | On a server you host | On a server someone else runs | |
|---|---|---|---|
| Where the model runs | your Apple Silicon Mac | a Mac or an NVIDIA GPU machine you run | wherever its operator runs it |
| Where your requests go | nowhere: they stay on your Mac | your server | that server |
| What you need | 32 GB of memory, ~18 GB of disk | the server: as for local, or a CUDA GPU; clients: only its address | its address, and a token if it asks for one |
| Set up with | ember model pull, then ember init | Remote inference or Hosted deployment | ember init --server-url URL |
Nothing is ever sent to a server you didn't configure. Without a terminal to ask (a script, CI), ember init sets up local inference; --local or --server-url answer the question up front.
A decision model is not a chat model: it takes a state plus a schema of typed questions and returns one probability per option, with no text generation. So ember plugs into agents as a tool, while their reasoning stays on their normal LLM:
ember/serving/server.py) loads the model once and stays warm across agent sessions.ember/mcp/mcp_server.py) never loads the model; it starts the model server on the first tool call, so the MCP handshake stays instant.| Thing | Name |
|---|---|
| Product, Python import, repository | ember |
Distribution (uv tool install, PyPI) | ember-advise, because ember is taken on PyPI and gut is held by an empty project |
| CLI | ember (short alias: gut; ember-advise too, so uvx ember-advise mcp works) |
| MCP server / command | ember / ember-mcp |
| Tool | advise — opencode: ember_advise; Claude Code: mcp__ember__advise (plugin: mcp__plugin_ember_ember__advise); Kilo Code: ember_advise |
| Playbook skill / MCP resource | ember-advise / ember://guide |
| Environment variables | EMBER_* |
"Clef" always refers to Cloudflare's upstream model, never to this product. Select a model with ember model pull / EMBER_MODEL= ; run ember model list to see every registered entry (flash, full).
A hosted deployment (e.g. Outerbounds) that supplies the model's S3 location directly at start time doesn't use this registry at all — see "Hosted deployment: a model location supplied at start time" below.
Tested versions and hardware are in COMPATIBILITY.md. Current accuracy and latency, from the latest tracked benchmark run, are on the benchmark report.
To use a server someone else runs, you need only Python 3.12 (managed by uv) and the server's address; skip ember model pull. To run the model yourself:
deployment/README.md.flash (9B), 96 GB or more for full (27B). Only 128 GB has been verified.flash or 55 GiB for full, in Hugging Face's shared cache (~/.cache/huggingface). Config, state, and logs live in ~/Library/Application Support/ember.uv tool install --python 3.12 ember-advise
ember model pull # ~18 GB, resumable, disk-space checked ember doctor # platform, dependencies, model, server, and agent registration ember init --opencode --global # register with opencode for every repo on this machine
Keep --python 3.12: uv otherwise picks your newest interpreter, which the pinned torch/transformers stack is not tested on.
This installs the latest released wheel from PyPI.
To pin a specific release tag from GitHub instead (no PyPI required):
uv tool install --python 3.12 "ember-advise @ git+https://github.com/shapeandshare/ember@v0.16.0"
The repository is public, so the git install needs no credentials. To use SSH instead, install from git+ssh://git@github.com/shapeandshare/ember@v0.16.0.
If you manage Python with conda, mamba, or pixi, install the same tool from the interim joshburt channel on Anaconda.org (it moves to conda-forge once that feedstock lands):
conda install -c joshburt -c conda-forge ember-advise # mamba and pixi take the same flags
Installed ember before the rename, as gut? Run uv tool uninstall gut first: both distributions provide the same commands.
Restart opencode and every repo on this machine gains ember_advise. The model server stays lazy — it starts on the first tool call (or with ember start).
Per-project skill and policy (run once in each repo you want ember-aware agents):
cd /path/to/your/repo
ember agents install --agent opencode # installs the ember-advise playbook skill ember agents show snippet >> AGENTS.md # then edit the project policy block at the end
The skill teaches the agent *when* to consult ember and *how* to ask; the AGENTS.md snippet adds a project-specific policy you customize (e.g. "check change risk before every push"). See Agent onboarding below for all harnesses and options.
flash targets the commit verified on MPS (17f0b0a) and full its release commit (2f3de3d, not yet verified locally) as a download convenience, and torch/torchvision are pinned to the tested minor series — but ember does not restrict itself to a hand-maintained allowlist of individually verified weights; it runs any model that fits its loader contract (constitution Article V, "Model Loading"). Set EMBER_MODEL_DIR to run another weights directory.
ember is Apple-Silicon-first locally, and supports NVIDIA GPUs for hosted deployment (constitution Article VI, "Apple Silicon and CUDA") — three devices total: run it on an Apple Silicon host with the memory above (MPS), on an NVIDIA GPU host (EMBER_DEVICE=cuda, float16 — see "Hosted deployment: a model location supplied at start time" and deployment/README.md for a full Outerbounds example), or on any host with the CPU fallback (EMBER_DEVICE=cpu — float32, roughly twice the memory, much slower). The HTTP server binds to loopback by default; to serve other machines set EMBER_HOST and set EMBER_SERVER_AUTH_TOKEN to require Authorization: Bearer (or any header name via EMBER_AUTH_HEADER, e.g. x-api-key, on the client side). Ember does not terminate TLS — front a remote-serving deployment with a proxy. Clients point at it with EMBER_SERVER_URL. See COMPATIBILITY.md and SECURITY.md.
Installing the tool is half the job; the other half is making agents want to consult it at the right moments and read its answers sensibly. ember/agent_kit/ ships that guidance through every channel each agent actually reads:
| Channel | opencode | Kilo Code | Claude Code | Codex CLI | How you get it |
|---|---|---|---|---|---|
| MCP server instructions (when to consult, how to ask, how to read answers) | ✅ in the system prompt | ✅ in the system prompt | ✅ (2 KB cap) | — | built in, nothing to do |
ember://guide resource (full playbook) | ✅ via read_mcp_resource | ✅ via read_mcp_resource | ✅ | — | built in |
ember-advise skill (playbook, loaded on demand) | ✅ | ✅ | ✅ | ✅ | ember agents install --agent |
| AGENTS.md / CLAUDE.md policy block | ✅ | ✅ | ✅ (CLAUDE.md) | ✅ | ember agents show snippet >> AGENTS.md |
ember init --opencode # opencode: config entry, plugin, and skill
ember init --kilocode # Kilo Code: kilo.json entry and skill ember init --codex # Codex CLI: .codex/config.toml entry and skill ember agents install --agent claude # .claude/skills/ember-advise/SKILL.md ember agents install --agent codex # .agents/skills/... (opencode reads this too) ember agents show snippet >> AGENTS.md # then edit the project policy at the end
The skill is a playbook, not a reference card: the decision points worth consulting ember about, copy-paste question sets for intent and readiness, failure triage, change risk, routing, and effort, and starting confidence thresholds calibrated from observed model output (re-measured whenever the pinned model revision changes). The snippet ends with a project policy — edit it to wire ember into your own workflow, e.g. "check change risk before every push".
Agent-specific notes:
.opencode/skills, .claude/skills, and .agents/skills, so install one copy per project to avoid duplicate listings.ember init --kilocode writes the mcp.ember entry to kilo.json (same config shape as opencode) and installs the skill to .kilo/skills/ember-advise/SKILL.md; the tool appears as ember_advise. Kilo Code also reads AGENTS.md automatically.claude mcp add --scope user ember -- ember-mcp (every project; drop --scope user to register it for the current project only); the tool appears as mcp__ember__advise. Or install the ember plugin, which bundles the MCP entry and the ember-advise skill (so skip ember agents install --agent claude): claude plugin marketplace add shapeandshare/ember
claude plugin install ember@ember
The plugin still runs the ember-mcp you installed with uv tool install, and its tool appears as mcp__plugin_ember_ember__advise. Use one route, not both, or the tool is listed twice.
ember init --codex writes [mcp_servers.ember] to .codex/config.toml (--global: ~/.codex/config.toml, or $CODEX_HOME/config.toml) and installs the skill to .agents/skills/ember-advise/SKILL.md. Codex loads a project .codex/config.toml oOnly the beginning is shown; read the rest in the repo