mon is an AI-native command line tool for Monarch Money. It gives local agents and scripts a fast, stable interface for account inspection, category review, transaction search, single-transaction category updates, and custom GraphQL access directly through your logged-in browser session.

Instead of storing API tokens or passwords that expire or risk CAPTCHA/MFA lockouts, mon communicates with Monarch through your active Chromium/Helium browser tab via bro. Your browser's normal session cookies and CSRF protections are reused without copying credentials to disk.

• mon auth status: verify active browser session and subscription entitlement.
• mon accounts: list accounts in a compact table or raw JSON.
• mon categories: list category ids, names, disabled state, and group metadata.
• mon transactions: search transactions by text and date with deterministic output.
• mon transaction update: update one exact transaction category with read-back verification.
• mon gql: run an arbitrary checked-in or ad-hoc GraphQL document.
• mon doctor: verify bro bridge connectivity and active Monarch tab status.
• mon install: copy the current binary into ~/.local/bin.

Install the optional agent skill for mon workflows:

npx skills@latest add xiaotianxt/mon -y

Install to a specific agent harness (such as Pi, Codex, or OpenCode):

npx skills@latest add xiaotianxt/mon --agent pi -y
npx skills@latest add xiaotianxt/mon --agent codex -y
npx skills@latest add xiaotianxt/mon --agent opencode -y

brew install xiaotianxt/tap/mon

Install the development build:

brew install --HEAD xiaotianxt/tap/mon

Requires a Rust toolchain.

git clone https://github.com/xiaotianxt/mon.git
cd mon
make install-local

make install-local installs mon to ~/.local/bin/mon. Make sure ~/.local/bin is in your PATH.

mon connects to the local bro MCP server (http://127.0.0.1:3500/mcp), locates an open Monarch tab (https://app.monarch.com/), and executes GraphQL queries and mutations inside that page using the browser's existing credentials and CSRF tokens.

No API tokens or credentials are saved to ~/.mon. To use mon:

1. Have bro running (bro doctor or bro serve).
2. Log in to https://app.monarch.com/ in your browser (Chrome or Helium) with the bro extension connected.
3. Run mon commands directly from your terminal.

Useful browser targeting options (when multiple tabs or browser instances are open):

mon accounts --browser-tab-id 1068097338
mon accounts --browser-id 545de677-bb20-4194-ac5f-c7073ac044e2

Show accounts:

mon accounts
mon accounts --json

Search transactions:

mon transactions --search coffee --start-date 2026-01-01 --end-date 2026-04-30
mon transactions --search "payroll" --limit 200 --json

List categories:

mon categories
mon categories --json

Preview a category change for one exact transaction:

mon transaction update TRANSACTION_ID --category "Groceries" --dry-run --json

Apply by exact category name or id:

mon transaction update TRANSACTION_ID --category "Groceries" --json
mon transaction update TRANSACTION_ID --category-id CATEGORY_ID --json

Category names are trimmed and matched exactly, case-insensitively. Missing, ambiguous, and disabled categories are rejected; use --category-id to resolve duplicate names. The update command never searches for transaction ids, performs bulk updates, creates rules, retries a mutation, or falls back to another GraphQL document.

A write succeeds only when read-back finds the requested category. Definitive payload or schema rejection returns failed. Network failures, timeouts, malformed mutation responses, conflicting observations, and failed read-back return outcome-unknown when the final state cannot be proven. Both states exit non-zero.

Update JSON contains status, changed, wouldChange, verified, transactionId, beforeCategory, and afterCategory. changed is null when the final state is unknown. During a dry run, afterCategory is the proposed target and verified is false.

Run an arbitrary GraphQL file:

mon gql \
  --operation GetAccounts \
  --query-file queries/accounts.graphql \
  --variables '{}'

• BRO_MCP_URL: bro MCP endpoint. Defaults to http://127.0.0.1:3500/mcp.
• BRO_SETTINGS: bro settings file. Defaults to ~/.bro/settings.json.

The former OPENBROWSERMCP_MCP_URL and OPENBROWSERMCP_SETTINGS names remain accepted as compatibility aliases.

mon is designed for agent use:

• every data command supports stable JSON output;
• no user credentials, passwords, or tokens are managed or saved;
• execution directly reuses the user's active browser session via bro;
• commands fail loudly with non-zero exits and contextual errors;
• the only built-in domain write targets one explicit transaction and category;
• write mutations are never retried automatically and success requires exact read-back verification.

make fmt
make check
cargo test

Maintainers can release with:

scripts/release.sh

The script runs tests, pushes a tag, waits for GitHub Actions to publish the darwin-arm64 release artifact, updates Formula/mon.rb in xiaotianxt/homebrew-tap, and verifies the Homebrew install.