Emerald MCP server

Emerald

The database under the chat. A local, file-based database that you and an AI model fill together, where every table has real types and real checks, so what you worked out stays true. Free software, AGPL-3.0. Desktop only, no server, no account. getemerald.dev

What Emerald is

as text and chosen per file. sqlite3 opens it, the schema is documented, and ordinary tools read every table, including the ones you declared.

• A document is a file. .emd, a real SQLite database on your disk, stored as SQLite bytes or

format: a real table with real types and a CHECK for every rule you state, not a template. A value that does not fit is refused when it is written, not found later.

• Declare a table for anything you keep: a charge, a paycheck, a book, a milestone. It is a

over the rows that point here. A total never quietly skips a row it cannot read.

• Formats link, and figures are worked out across them: hours from a start and an end, a total

paid. Each one is proved, failed or unchecked, and unchecked says why.

• Claims are rules that have to hold: the receipt total is the card charge, every hour was

folder of them. The columns are placed once, kept as a reader, and checked every time. A model may give a mapping or a position, never a value.

• Files are read onto formats: a spreadsheet, a CSV, a JSON file of rows, a Markdown note or a

shaped tools, never a general query: 28 for any document, 85 with the ledger. Every write is a dry run until you say commit; a copy is kept beside the document before any write; a document older than the server's schema is never migrated, only reported.

• A model works in it through MCP. The server reads and writes the document directly, with

it as the app does, where the host supports MCP Apps (seen in the Claude desktop app's Code tab and in VS Code's Copilot Chat); everywhere else, the same answer as text.

• It draws in the conversation. Ask to see a sheet, a board or a roadmap and the server draws

the ledger and the development pack. Making and sharing your own is next.

• Packs are formats somebody already worked out, with their views. Two come with Emerald:

telemetry — and a test fails if it ever does, with one exception you choose: updates, off by default. Turned on, it asks GitHub for the newest version number once a day, and on Windows downloads a newer one from its GitHub release; Help → Check for Updates Now asks once. A local model runtime on this machine can be used, and looking for one happens only on your click, over loopback.

• No internet, no login. The app makes no network call of its own — not for AI, not for

The ledger

place that is theirs.

• For people who want to manage their money, not be managed by it: everything they have, in one

showed the deduction.

• Reads what you already get: card statements, bank exports, payslips, fund reports.
• Files every charge, and tells a transfer from a spend and a monthly bill from a one-off.
• Every total opens to the rows it was summed from.
• A year of study-fund reports read in: one month the fund received nothing, though the payslip

• Nothing connects to your bank. You give it the files.

The development pack

decision already taken is answered with the decision.

• A project's memory as rows: milestones, units, decisions, open questions, an inbox.
• A session starts from the rows, not from a summary of a chat. A request that contradicts a

starts with it.

• One project's session leaves a note in another project's inbox, and the next session there

session on this repository starts by asking it.

• Emerald is built with it: docs/memory.emd is this project's memory, and every

• Setting a repository up is one command, run in its folder (from 0.2.0):

Shortened. The full README is on GitHub.