Meridian

Meridian

Shared, structured project state for long-running AI coding work.

Source-available MCP server for persistent project state — shared task log, pinned decisions, human-in-the-loop queue, and tiered handoffs. Works with Claude Code, Cursor, Cline, Claude Desktop, or any MCP client.

Built-in agent memory (for example Claude Code's CLAUDE.md files and auto memory) keeps notes as files for that agent. Meridian adds a shared, queryable project record that several sessions and different MCP clients can read and update. It works alongside built-in memory rather than replacing it.

Why Meridian

Every AI coding session boots blind. You re-explain the architecture, re-describe the constraints, re-list what's been tried. When context fills up mid-task, detail is lost. This is context debt — and it compounds.

Meridian gives your sessions shared memory. They see the same task log, the same pinned decisions, the same goal state. When context fills up, a new session resumes from a compressed handoff. No copy-paste, no re-explaining from scratch.

What it is, in 30 seconds

A local MCP server every AI session connects to. They share goal state, see each other's task log, and resume from a compressed handoff when context fills up.

Two ways to run Meridian:

• Self-host — free forever, any team size. Clone and run in 2 commands.
• Hosted at usemeridian.us — 30 days free (no card), then $20/mo Standard.

Quickstart

Option 1 — binary release (recommended)

Prebuilt downloads are attached to every GitHub release. They are unsigned; each release includes a SHA256SUMS file to check downloads against.

• Windows tray app (meridian-tray.exe): a system-tray icon that runs the dashboard server. Choose Open Dashboard from the tray menu, which opens http://127.0.0.1:7878.
• macOS tray app (meridian-tray-mac.dmg): the same tray app. The app is not notarized, so the first launch needs right-click > Open.
• Linux: there is no tray app yet. Use the uv install below.
• meridian.exe, meridian-linux, meridian-mac-arm64: the tunnel client only (meridian --tunnel --repo ., Pro plan and API token required). They do not serve the dashboard.

Dashboard via uv (Linux, macOS, Windows):

uv tool install meridian-server

meridian

Dashboard opens at http://localhost:7878. The data directory defaults to ./data; set MERIDIAN_DATA_DIR to change it.

Pro tunnel client (optional):

meridian --tunnel --repo .

Linux / macOS (installer script, uses uv):

curl -fsSL https://usemeridian.us/install.sh | sh

Windows (PowerShell, installs the tunnel client `meridian.exe`):

irm https://usemeridian.us/install-windows.ps1 | iex

Option 2 — from source (dev setup / self-host)

Linux / macOS:

git clone https://github.com/meridianmcp/Meridian

cd Meridian ./install.sh pixi run start

Windows (PowerShell):

git clone https://github.com/meridianmcp/Meridian

cd Meridian .\install.ps1 pixi run start

Dashboard opens at http://localhost:7878. Data persists in ./data/meridian.db.

Wire it into your AI client

Claude Code

Drop a .mcp.json at your project root.

Hosted (no install) — generate an API key at usemeridian.us/settings:

{

"mcpServers": { "meridian": { "type": "http", "url": "https://usemeridian.us/mcp", "headers": { "Authorization": "Bearer sk_meridian_YOUR_KEY_HERE" } } } }

Self-host (from source):

{

"mcpServers": { "meridian": { "command": "pixi", "args": ["run", "python", "-m", "meridian", "--mcp"], "cwd": "/absolute/path/to/Meridian" } } }

Self-host (tray app or uv install already running on port 7878):

{

"mcpServers": { "meridian": { "type": "http", "url": "http://127.0.0.1:7878/mcp" } } }

Use the same `mcpServers` key in `~/.claude.json` to make it available in every project. A self-hosted server needs no API key. If you set `MERIDIAN_PORT`, change the port in the URL to match.

Cursor / Windsurf

Same JSON snippet — both clients read .mcp.json from the project root.

Claude Desktop

Add the same mcpServers block to:

• Windows: %APPDATA%\Claude\claude_desktop_config.json
• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

Restart Claude Desktop. New chats have Meridian tools. If a newly deployed tool is still missing, follow the MCP tool-surface freshness guide before editing any client cache.

claude.ai web (recommended for planning chat)

A claude.ai connector cannot reach http://localhost. Pick one of these:

• Hosted (no install): in claude.ai go to Customize > Connectors > Add custom connector, set the URL to https://usemeridian.us/mcp, and complete the OAuth prompt.
• Self-hosted, Chrome bridge: use dnakov/claude-mcp, included as a submodule:

  git clone --recurse-submodules https://github.com/meridianmcp/Meridian

Open chrome://extensions, enable Developer mode, click Load unpacked, and select extensions/claude-mcp. Set the bridge URL to http://localhost:7878/mcp/sse.

• Self-hosted, public URL: expose your server over HTTPS and add https:// /mcp as the connector.

Full steps are in the browser connector guide.

Hosted tier (no install)

Sign in at usemeridian.us → Settings → MCP client setup → Generate API key → Copy config.

Or manually:

{"mcpServers":{"meridian":{"type":"http","url":"https://usemeridian.us/mcp","headers":{"Authorization":"Bearer sk_meridian_YOUR_KEY_HERE"}}}}

claude.ai (browser) users: no extension is needed for hosted Meridian. Add https://usemeridian.us/mcp under Customize > Connectors. See the browser connector guide.

Get your API key at usemeridian.us/settings after sign-in. Free tier: 30 days, no card, full features.

What you get

• Dashboard at http://localhost:7878 — sessions, tasks, sprint board, swimlane timeline, HITL queue, pinned decisions.
• MCP tools — start_session, log_task, claim_task, set_decision, pin_decision, request_hitl, generate_handoff, and ~50 more.
• Symbol-level parallel safety — claim_file can claim a single class or function (parsed with ast / tree-sitter) so two sessions edit the same file safely; an overlapping claim is blocked with the free symbols listed.
• Live work queue — planners inject sprint items mid-run; executors pick them up at the next item boundary via a board_change signal, no interruption.
• HITL recommended option — request_hitl can flag a safe-default option the dashboard highlights; Enter submits it, number keys pick others.
• GitHub hub (hosted) — connect your repo once in Settings; sessions get read_file, list_files, meridian_github_search_code, git_log, and meridian_github_get_commit injected automatically. No extra install.
• Tiered handoffs — L0/L1/L2 compression so a fresh session can pick up where the last one stopped.
• Webhook intake — push events from LangGraph / Autogen / custom agents into the same dashboard.
• Works everywhere — Claude Code, Claude Desktop, Cursor, Windsurf, LangGraph, custom.

How it works

> start_session(project_id="meridian", session_name="feature-x")

✓ session registered · sprint loaded · 12 active tasks

get_tasks(project_id="meridian", limit=5)

[DONE] backend / wire decisions_pinned table [PENDING] frontend / add notes vtab (claimed by session-2)

claim_task(task_id="a1f3...")

✓ claimed — other sessions skip this one

State lives in data/meridian.db (SQLite) or a Postgres URL via MERIDIAN_DB_URL. No cloud required for local use.

Team coordination

Point MERIDIAN_DB_URL at a shared Postgres (Neon free tier works great). Every teammate runs their own local Meridian against the same DB — instant shared sessions, no Meridian server in the cloud.

Auto-checkpoint with hooks

One command wires Claude Code and Codex to Meridian. Every session start injects your project context automatically. Every session end snapshots completed work and writes a delta handoff.

Mac/Linux:

curl -fsSL https://usemeridian.us/hooks.sh | bash

Windows:

irm https://usemeridian.us/hooks.ps1 | iex

Prompts for your Meridian server URL (default http://localhost:7878), then opens your browser to connect this machine — no project ID or API token to paste. Writes to ~/.claude/settings.json (Claude Code) or ~/.codex/config.toml (Codex). After setup, every session automatically:

1. On start — calls POST /hooks/session-start → injects goal, sprint items, recent tasks, and pinned decisions into the session context via additionalContext.
2. On stop — calls POST /hooks/stop → runs auto_capture and writes a delta handoff so the next session resumes from where this one ended.

No more manual start_session() calls. No lost work when context fills.

Hosted tier

30-day free trial · no card required

License

MSL-1.0 — free for local and internal use at any team size. Paid license required if you host Meridian as a service for others. Converts to MIT after 6 years.

For licensing questions: hello@usemeridian.us

Contributors

Built by @ajc3xc

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