Most AI agents forget you by morning, run whatever the model decides, and stop the moment you close the laptop. Mercury doesn't.
Mercury is an open-source agent with a personality you write yourself, a memory that stays on your disk, and a permission system that sits between the model and your machine. Message it from your terminal, Telegram, Discord, Slack or Signal and you reach the same agent, with the same memory, running as one background process you own.
It reads and writes your files, runs commands, ships code through git and GitHub, researches the web and keeps a schedule. Every one of those actions is checked against rules you set, and every turn stays inside a daily token budget.
Then it goes further:
- Mercury Code turns it into a careful pair programmer inside your repository, one that only says "done" after the tests pass.
- Mercury Bots gives it a team. Persistent specialists research, write and ship on their own schedule, then drop finished files in a folder you can open, or straight into your Telegram chat.
Install it in one line. Talk to it from anywhere. It is still there tomorrow, and it still remembers.
At a glance
| |
|---|
| Install | One-line installer with no Node.js required, or npm i -g @cosmicstack/mercury-agent on Node.js 22+ |
| Runs on | macOS, Linux, Windows, and Android via Termux |
| Talk to it from | Terminal UI, Telegram, Discord, Slack, Signal, and a local web dashboard |
| Models | DeepSeek, OpenAI, Anthropic, Grok, Ollama (cloud and local), LM Studio, any OpenAI-compatible endpoint, Mercury Cloud, and more, with automatic fallback |
| Safety | Shell blocklist, per-folder read/write scopes, approval prompts, SSRF-guarded fetches, secret redaction in logs |
| Memory | Second Brain: typed, deduplicated facts in SQLite with full-text search, all on your disk |
| Tools | About 50 built in (files, shell, git, GitHub, web, scheduler, memory, sub-agents) plus installable skills |
| Always on | Background daemon with crash recovery and a login service on every OS |
| License | MIT |
Why Mercury
Most agents can read files, run commands and fetch pages. The differences are in what happens around those actions, and that is where Mercury puts its effort.
It asks before it acts. File access is scoped per folder, shell commands pass through a blocklist and an approval step, and outbound requests are checked against private address ranges. You choose per session whether Mercury asks every time or runs freely, and members of a shared Telegram or Discord channel cannot widen their own access.
It remembers you without being told to. After each conversation Mercury extracts a few durable facts (preferences, goals, projects, decisions) with confidence scores, resolves conflicts with what it already knows, and recalls the relevant ones before the next answer. Everything lives in a SQLite file under ~/.mercury, and /memory lets you inspect, pause or clear it.
It respects a budget. A daily token budget is enforced on every turn. When usage climbs, Token Saver mode trims context and can route routine work to a cheaper model. /budget shows where you stand.
It is one runtime, not a collection of scripts. A single background process owns your channels, your bots and the web dashboard. Running mercury in a terminal attaches to that process instantly, so closing the terminal never stops a running task or a bot.
It writes code like a careful engineer. Mercury Code plans and builds in one flow, shows a live checklist, asks once before large changes, and only reports success after a build, test or typecheck actually passes.
It works while you are away. Mercury Bots are persistent specialists with their own persona, model, memory, permissions and daily budget. They run on schedules, hand work to each other, and deliver finished files to ~/Documents/Mercury/<Bot name>/. You can manage the whole fleet from Telegram with buttons.
You own the personality. Mercury's character is defined by plain Markdown files (soul.md, persona.md, taste.md, heartbeat.md) that you can edit.
Quickstart
1. Install. The installer downloads a standalone binary for your OS and CPU and verifies its checksum. No Node.js needed.
# macOS / Linux
curl -fsSL https://mercuryagent.sh/install.sh | sh
# Windows (PowerShell)
irm https://mercuryagent.sh/install.ps1 | iex
Prefer npm? Mercury needs Node.js 22 or newer on that path.
npm i -g @cosmicstack/mercury-agent
2. Run it.
mercury
The first run starts a short setup wizard: your name, the agent's name, Mercury Cloud or your own API keys, and optional channels such as Telegram. Mercury then starts its background service and opens the terminal UI.
3. Use it every day.
mercury # open a chat (attaches to the running Mercury)
mercury code . # open Mercury Code in the current repository
mercury doctor # change providers, keys or channels; applies immediately
mercury status # see what is running
Upgrades are one command: mercury upgrade. It does nothing if you are already on the latest version.
How it works
flowchart LR
subgraph You
T[Terminal UI]
TG[Telegram]
DC[Discord / Slack / Signal]
W[Web dashboard]
end
subgraph Runtime["Mercury runtime (one background process)"]
A[Agent loop]
P[Permissions]
M[(Second Brain<br/>SQLite)]
B[Mercury Bots]
S[Scheduler]
end
LLM[LLM providers<br/>with fallback]
T -- attach --> A
TG --> A
DC --> A
W --> A
A --> P
A <--> M
A --> LLM
B --> LLM
S --> A
S --> B
This is the beginning of the README. Read the rest at the original. Read the full README ↗
