mercury-agent

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

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

The runtime runs as a login service (LaunchAgent on macOS, systemd on Linux, Task Scheduler on Windows) and restarts itself after a crash. Every channel talks to the same agent, the same permissions and the same memory. The terminal is a client: mercury attaches to the runtime, and mercury code opens a coding session beside it.

Features

Channels

When more than one channel is configured, notifications go to the first available one in order: Signal, Telegram, Discord, Slack, terminal.

Mercury Code

A full-screen coding environment that works inside a repository.

mercury code [dir]   # from the shell
/code                # from a running chat

• AUTO mode: plans and builds in one pass, and asks once before large or risky changes.
• Verified completion: a task ends as done only w