Monarch Money

WORKING SLICE
Import household transaction CSVs, reconcile opening/closing balances and review shared monthly spending and goal progress. Track assets with explicitly dated manual values and keep a record of category changes.

Build this scoped Monarch Money-inspired workflow with a documented data model and visible failure states.

Architecture
- Node.js, TypeScript and Express with server-rendered HTML and small browser modules.
- SQLite through better-sqlite3 with migrations, prepared statements and a single background worker.
- Integer minor units or a decimal library for money; CSV parsers with explicit date, currency and sign mapping.

Prerequisites and limits
A supported Node release, a writable local data directory and a separate backup location. Bind to localhost; remote use requires authentication and HTTPS first.
Outside this release: bank/investment sync; transaction categorization

Data model and correctness
household accounts, statement imports, transfer pairs, category budgets, goals and source-dated valuations
Invariant: Transfers cannot inflate household income; mixed currencies require an explicit conversion method and estimates stay separate from actual balances.
Use short SQLite transactions and persist job state before starting work. Give retries stable operation IDs; report incomplete or unknown results instead of silently repeating them.

Security and privacy
Reject unexpected origins and unbounded request bodies even on localhost. Keep credentials outside the database export and redact sensitive text from logs. No bank credentials in uploads or logs; restrict exports and backups to the owner. Never initiate transfers or infer investment suitability.

Recovery and export
Use a consistent SQLite backup and an attachment manifest. Export portable JSON/CSV, then restore to a new directory without overwriting the original data.

Implementation order
1. Phase 1 — Scope and fixtures. Implement this bounded workflow: Import household transaction CSVs, reconcile opening/closing balances and review shared monthly spending and goal progress. Track assets with explicitly dated manual values and keep a record of category changes. Record prerequisites, select representative user-owned fixtures and document the unsupported features: bank/investment sync; transaction categorization
2. Phase 2 — Durable model. Model household accounts, statement imports, transfer pairs, category budgets, goals and source-dated valuations Add migrations or a versioned document format, explicit validation, stable IDs and a visible import-error report. Preserve this rule: Transfers cannot inflate household income; mixed currencies require an explicit conversion method and estimates stay separate from actual balances.
3. Phase 3 — Complete the first useful path. Implement the workflow's input, review and output interface, with clear controls and explicit empty/error states. Use short SQLite transactions and persist job state before starting work. Give retries stable operation IDs; report incomplete or unknown results instead of silently repeating them.
4. Phase 4 — Permissions and integration failure. Reject unexpected origins and unbounded request bodies even on localhost. Keep credentials outside the database export and redact sensitive text from logs. No bank credentials in uploads or logs; restrict exports and backups to the owner. Never initiate transfers or infer investment suitability. Request integration credentials and permissions only for the enabled feature; show a disconnected state instead of mock results.
5. Phase 5 — Portable handoff. Use a consistent SQLite backup and an attachment manifest. Export portable JSON/CSV, then restore to a new directory without overwriting the original data. Include setup, operating limits, fixture walkthrough and shutdown/restart instructions in the README.
6. Phase 6 — Acceptance scenarios. Reconcile two sides of a transfer and preserve the household total; reimport a statement without duplicating an expense. Repeat the workflow after restart and with a denied permission or unavailable dependency; show recoverable failure rather than a success placeholder.

Acceptance
Reconcile two sides of a transfer and preserve the household total; reimport a statement without duplicating an expense.
Use real source data or clearly labeled fixtures. Explain unsupported input and provider failures; do not fabricate analytics, delivery receipts, accuracy claims or security guarantees.

Optional agent guidance
Optional external skill: [xlsx](https://github.com/anthropics/skills/blob/main/skills/xlsx/SKILL.md) — Create, edit and inspect spreadsheet files, formulas, formatting and tabular imports or exports. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Optional external skill: [sharp-edges](https://github.com/trailofbits/skills/blob/main/plugins/sharp-edges/skills/sharp-edges/SKILL.md) — Review security-sensitive APIs and configuration for dangerous defaults and easy-to-misuse interfaces. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Optional external skill: [web-design-guidelines](https://github.com/vercel-labs/agent-skills/blob/main/skills/web-design-guidelines/SKILL.md) — Review web interfaces for accessibility, keyboard focus, forms, navigation and interaction quality. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Project rule — data model: household accounts, statement imports, transfer pairs, category budgets, goals and source-dated valuations
Project rule — preserve this invariant: Transfers cannot inflate household income; mixed currencies require an explicit conversion method and estimates stay separate from actual balances.
Project rule — acceptance evidence: Reconcile two sides of a transfer and preserve the household total; reimport a statement without duplicating an expense.

# AGENTS.md — Build guide for Monarch Money

## Project scope
Import household transaction CSVs, reconcile opening/closing balances and review shared monthly spending and goal progress. Track assets with explicitly dated manual values and keep a record of category changes.

Catalogue verdict: kinda. A manual finance dashboard is buildable, but high-quality bank aggregation, transaction cleaning, investment data, household collaboration, and mobile sync make it real work.
Use the implementation prompt below to define the deliverable. Complete each phase's acceptance checks before extending the scope.

## Working agreement
- Inspect the repository and its existing instructions before choosing paths, dependencies or commands. Keep one coherent stack and explain changes to the proposed architecture.
- Plan a vertical slice that accepts a real input and produces the useful output described below. Persist only the state the prompt calls for; respect memory-only and upstream-managed workflows. Use fixtures only when they are clearly labelled.
- After scaffolding, document the actual install, development, check and build commands in README and keep them synchronized with the package or project manifest. Do not report commands as successful unless they ran.
- Work in small steps. At handoff, list implemented flows, checks actually performed, remaining blockers, and any credentials or provider setup the owner must supply.
- Do not publish, spend money, contact customers, delete source data or run irreversible migrations without the project owner's authorization.

## Prerequisites
- A supported Node release, a writable local data directory and a separate backup location. Bind to localhost; remote use requires authentication and HTTPS first.
- Implementation components: Node.js, TypeScript and Express with server-rendered HTML and small browser modules. SQLite through better-sqlite3 with migrations, prepared statements and a single background worker. Integer minor units or a decimal library for money; CSV parsers with explicit date, currency and sign mapping.
- Scope boundary: bank/investment sync; transaction categorization

## Stack and architecture
- Node.js, TypeScript and Express with server-rendered HTML and small browser modules.
- SQLite through better-sqlite3 with migrations, prepared statements and a single background worker.
- Integer minor units or a decimal library for money; CSV parsers with explicit date, currency and sign mapping.
- Domain model: household accounts, statement imports, transfer pairs, category budgets, goals and source-dated valuations

## Security and data integrity
- Reject unexpected origins and unbounded request bodies even on localhost. Keep credentials outside the database export and redact sensitive text from logs. No bank credentials in uploads or logs; restrict exports and backups to the owner. Never initiate transfers or infer investment suitability.
- Correctness boundary: Transfers cannot inflate household income; mixed currencies require an explicit conversion method and estimates stay separate from actual balances.
- Use short SQLite transactions and persist job state before starting work. Give retries stable operation IDs; report incomplete or unknown results instead of silently repeating them.
- Use a consistent SQLite backup and an attachment manifest. Export portable JSON/CSV, then restore to a new directory without overwriting the original data.

## Agent implementation rules
- Project rule — data model: household accounts, statement imports, transfer pairs, category budgets, goals and source-dated valuations
- Project rule — preserve this invariant: Transfers cannot inflate household income; mixed currencies require an explicit conversion method and estimates stay separate from actual balances.
- Project rule — acceptance evidence: Reconcile two sides of a transfer and preserve the household total; reimport a statement without duplicating an expense.

## Optional agent skills and references
- Optional external skill: [xlsx](https://github.com/anthropics/skills/blob/main/skills/xlsx/SKILL.md) — Create, edit and inspect spreadsheet files, formulas, formatting and tabular imports or exports. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
- Optional external skill: [sharp-edges](https://github.com/trailofbits/skills/blob/main/plugins/sharp-edges/skills/sharp-edges/SKILL.md) — Review security-sensitive APIs and configuration for dangerous defaults and easy-to-misuse interfaces. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
- Optional external skill: [web-design-guidelines](https://github.com/vercel-labs/agent-skills/blob/main/skills/web-design-guidelines/SKILL.md) — Review web interfaces for accessibility, keyboard focus, forms, navigation and interaction quality. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.

Read the linked SKILL.md and its dependencies before adding a skill. Select only the skills matching this project's runtime and task; their documentation does not supply API access, credentials or approval to perform external actions. Pin the reviewed revision where the tool supports it. Follow the chosen agent's documented project-level installation mechanism.

## Distribution ideas
These are optional planning notes. Obtain the owner's approval before publishing or contacting anyone.
- Demonstrate the actual Monarch Money-inspired workflow with owned or clearly labeled sample data: Import household transaction CSVs, reconcile opening/closing balances and review shared monthly spending and goal progress. Track assets with explicitly dated manual values and keep a record of category changes.
- Publish a reproducible walkthrough with this observable result: Reconcile two sides of a transfer and preserve the household total; reimport a statement without duplicating an expense.
- Explain who can operate this scoped tool, its setup and ongoing costs, and these remaining product gaps: bank/investment sync; transaction categorization Avoid guaranteed savings, performance scores or implied endorsement.

## Engineering roadmap
1. Phase 1 — Scope and fixtures. Implement this bounded workflow: Import household transaction CSVs, reconcile opening/closing balances and review shared monthly spending and goal progress. Track assets with explicitly dated manual values and keep a record of category changes. Record prerequisites, select representative user-owned fixtures and document the unsupported features: bank/investment sync; transaction categorization
2. Phase 2 — Durable model. Model household accounts, statement imports, transfer pairs, category budgets, goals and source-dated valuations Add migrations or a versioned document format, explicit validation, stable IDs and a visible import-error report. Preserve this rule: Transfers cannot inflate household income; mixed currencies require an explicit conversion method and estimates stay separate from actual balances.
3. Phase 3 — Complete the first useful path. Implement the workflow's input, review and output interface, with clear controls and explicit empty/error states. Use short SQLite transactions and persist job state before starting work. Give retries stable operation IDs; report incomplete or unknown results instead of silently repeating them.
4. Phase 4 — Permissions and integration failure. Reject unexpected origins and unbounded request bodies even on localhost. Keep credentials outside the database export and redact sensitive text from logs. No bank credentials in uploads or logs; restrict exports and backups to the owner. Never initiate transfers or infer investment suitability. Request integration credentials and permissions only for the enabled feature; show a disconnected state instead of mock results.
5. Phase 5 — Portable handoff. Use a consistent SQLite backup and an attachment manifest. Export portable JSON/CSV, then restore to a new directory without overwriting the original data. Include setup, operating limits, fixture walkthrough and shutdown/restart instructions in the README.
6. Phase 6 — Acceptance scenarios. Reconcile two sides of a transfer and preserve the household total; reimport a statement without duplicating an expense. Repeat the workflow after restart and with a denied permission or unavailable dependency; show recoverable failure rather than a success placeholder.

## Paid-product capabilities outside this build
- bank/investment sync
- transaction categorization
- household collaboration
- mobile apps
- support
- data security posture

## Implementation prompt
WORKING SLICE
Import household transaction CSVs, reconcile opening/closing balances and review shared monthly spending and goal progress. Track assets with explicitly dated manual values and keep a record of category changes.

Build this scoped Monarch Money-inspired workflow with a documented data model and visible failure states.

Architecture
- Node.js, TypeScript and Express with server-rendered HTML and small browser modules.
- SQLite through better-sqlite3 with migrations, prepared statements and a single background worker.
- Integer minor units or a decimal library for money; CSV parsers with explicit date, currency and sign mapping.

Prerequisites and limits
A supported Node release, a writable local data directory and a separate backup location. Bind to localhost; remote use requires authentication and HTTPS first.
Outside this release: bank/investment sync; transaction categorization

Data model and correctness
household accounts, statement imports, transfer pairs, category budgets, goals and source-dated valuations
Invariant: Transfers cannot inflate household income; mixed currencies require an explicit conversion method and estimates stay separate from actual balances.
Use short SQLite transactions and persist job state before starting work. Give retries stable operation IDs; report incomplete or unknown results instead of silently repeating them.

Security and privacy
Reject unexpected origins and unbounded request bodies even on localhost. Keep credentials outside the database export and redact sensitive text from logs. No bank credentials in uploads or logs; restrict exports and backups to the owner. Never initiate transfers or infer investment suitability.

Recovery and export
Use a consistent SQLite backup and an attachment manifest. Export portable JSON/CSV, then restore to a new directory without overwriting the original data.

Implementation order
1. Phase 1 — Scope and fixtures. Implement this bounded workflow: Import household transaction CSVs, reconcile opening/closing balances and review shared monthly spending and goal progress. Track assets with explicitly dated manual values and keep a record of category changes. Record prerequisites, select representative user-owned fixtures and document the unsupported features: bank/investment sync; transaction categorization
2. Phase 2 — Durable model. Model household accounts, statement imports, transfer pairs, category budgets, goals and source-dated valuations Add migrations or a versioned document format, explicit validation, stable IDs and a visible import-error report. Preserve this rule: Transfers cannot inflate household income; mixed currencies require an explicit conversion method and estimates stay separate from actual balances.
3. Phase 3 — Complete the first useful path. Implement the workflow's input, review and output interface, with clear controls and explicit empty/error states. Use short SQLite transactions and persist job state before starting work. Give retries stable operation IDs; report incomplete or unknown results instead of silently repeating them.
4. Phase 4 — Permissions and integration failure. Reject unexpected origins and unbounded request bodies even on localhost. Keep credentials outside the database export and redact sensitive text from logs. No bank credentials in uploads or logs; restrict exports and backups to the owner. Never initiate transfers or infer investment suitability. Request integration credentials and permissions only for the enabled feature; show a disconnected state instead of mock results.
5. Phase 5 — Portable handoff. Use a consistent SQLite backup and an attachment manifest. Export portable JSON/CSV, then restore to a new directory without overwriting the original data. Include setup, operating limits, fixture walkthrough and shutdown/restart instructions in the README.
6. Phase 6 — Acceptance scenarios. Reconcile two sides of a transfer and preserve the household total; reimport a statement without duplicating an expense. Repeat the workflow after restart and with a denied permission or unavailable dependency; show recoverable failure rather than a success placeholder.

Acceptance
Reconcile two sides of a transfer and preserve the household total; reimport a statement without duplicating an expense.
Use real source data or clearly labeled fixtures. Explain unsupported input and provider failures; do not fabricate analytics, delivery receipts, accuracy claims or security guarantees.

Optional agent guidance
Optional external skill: [xlsx](https://github.com/anthropics/skills/blob/main/skills/xlsx/SKILL.md) — Create, edit and inspect spreadsheet files, formulas, formatting and tabular imports or exports. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Optional external skill: [sharp-edges](https://github.com/trailofbits/skills/blob/main/plugins/sharp-edges/skills/sharp-edges/SKILL.md) — Review security-sensitive APIs and configuration for dangerous defaults and easy-to-misuse interfaces. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Optional external skill: [web-design-guidelines](https://github.com/vercel-labs/agent-skills/blob/main/skills/web-design-guidelines/SKILL.md) — Review web interfaces for accessibility, keyboard focus, forms, navigation and interaction quality. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Project rule — data model: household accounts, statement imports, transfer pairs, category budgets, goals and source-dated valuations
Project rule — preserve this invariant: Transfers cannot inflate household income; mixed currencies require an explicit conversion method and estimates stay separate from actual balances.
Project rule — acceptance evidence: Reconcile two sides of a transfer and preserve the household total; reimport a statement without duplicating an expense.

## Completion evidence
Demonstrate the prompt's acceptance scenarios against the scoped workflow. Include setup from a clean checkout and failure recovery. Check persistence across restart and export/restore only for the state the prompt says to store; for memory-only tools, confirm that temporary content is discarded as specified. Record actual results and remaining limitations. A detailed plan alone does not establish a working replacement.