## Why
You could not add a transaction by hand to a bank-connected account.
There was no good reason for it: bank sync **only inserts** rows it has
not seen before (dedup runs on `dedup_fingerprint` /
`external_transaction_id`, both `null` on manual rows) and **never
deletes or updates**, so a hand-entered transaction survives every later
sync untouched.
The one thing that genuinely does not make sense is letting a user set a
**balance** on a connected account, because the next sync overwrites it.
That restriction stays.
## What was actually blocking it
Less than it looked. The HTTP endpoint already allowed it,
`ManualBalanceAdjuster` already skipped connected accounts, and the
transaction dialog already handled them (it forces `updateBalance:
false`). Only two surfaces blocked it:
- **MCP** — `WriteTool::writableAccount()` rejected every connected
account for *all* writes. Split into `accountInSpace()` (no connection
check — used by `create_transaction` / `update_transaction`) and
`balanceWritableAccount()` (still rejects connected — used by
`create_balance`).
- **The account detail page** — hid its "Add transaction" button for
connected accounts, even though the same dialog on the transactions page
already offered them in its account picker.
## Also in here
Two problems the change surfaced, both fixed:
- **`EnableBankingSyncer` linked-account watermark** took the newest
transaction of *any* source. With manual rows now able to land on a
connected account, one dated later than the bank's last posting would
shrink the fetch window and skip the bank history in between —
permanently, since the watermark only moves forward. On the QA data this
would have skipped **36 days**. Now restricted to bank-sourced rows.
- **`calculateHistoricalBalances`** derives history by walking back from
a bank-provided reference balance, summing transactions unfiltered.
Counting a hand-entered row subtracts money the bank never had. Now
walks bank-sourced rows only. (Safe before only because manual rows
could not reach a connected account.)
Plus the honesty/copy work:
- `ManualBalanceAdjuster` returns whether it shifted anything, so
`create` / `update` / `delete_transaction` all report `balance_updated`
instead of silently no-opping and letting the agent claim a balance
moved.
- The **OAuth consent screen** and the AI Connector settings page said
"bank-connected accounts stay read-only". That was a trust statement,
and it is no longer true — both now say bank-*synced transactions*
cannot be edited or deleted and connected balances stay untouched.
- `create_balance`'s description no longer contradicts the server
instructions shipped alongside it.
- The transaction dialog now *explains* why the "Update account balance"
checkbox is absent on a connected account instead of just hiding it (it
defaults to on and is localStorage-persisted, so it used to vanish
mid-form with no reason given).
## What stays blocked
- Balances on connected accounts — MCP `create_balance` rejects them,
the adjuster no-ops, the UI shows the explanation instead of the
checkbox.
- Editing or deleting bank/imported transactions — still gated on
`source === manually_created`, unchanged.
## Testing
- `create_transaction` on a connected account leaves its balances alone;
moving a transaction onto a connected account unwinds only the manual
side it came from.
- A manual row survives a sync and does not block the bank's own rows —
the invariant the whole change rests on, previously untested.
- A manual transaction does not move the linked-account sync window.
- The account page offers "Add transaction" on connected accounts, and
hides it on non-transactional ones.
- Full suite: 2047 passing, phpstan clean.
QA'd in the browser end to end (create from a connected account, edit it
afterwards, contrast with a manual account, switch accounts mid-form)
and over real MCP calls against the running server (`create_transaction`
returned `balance_updated: false` on connected / `true` on manual;
`create_balance` refused the connected account).
## Demo
https://github.com/user-attachments/assets/7a7f1cbb-8f68-402d-ba35-3288dd7ea77f
<!-- PLACEHOLDER: drag the video here -->
## MCP Phase 2 — write tools
> **Stacked on #689** (`mcp-functionality`). Base this PR on
`mcp-functionality`, not `main`, and merge it **after** #689.
Phase 1 shipped a read-only MCP server for Pro accounts. This adds the
**write** surface and re-enables the read/read-write token scope the UI
dropped in PR1.
### Write tools
A new `WriteTool` base extends `McpTool`: on top of the Pro-plan gate it
requires the calling token to carry `mcp:write`, returning a clear error
for read-only tokens. Each concrete tool is annotated `#[IsDestructive]`
(PHP attributes aren't inherited, so the annotation lives on each tool,
not the base — a docblock on `WriteTool` notes this).
- `create_transaction` — manual (non-connected) accounts only; forces
`source = manually_created`.
- `update_transaction` / `delete_transaction` — manually-created
transactions only; bank/imported ones stay locked.
- `categorize_transaction` — sets/clears the category on **any**
transaction (imported included), marking it `category_source = manual`.
- `label_transaction` — add/remove labels on **any** transaction.
- `create_balance` — balance snapshot on manual accounts only.
- `create_category` / `update_category` / `delete_category` — mirrors
the settings controller (parent/depth/cycle rules, cashflow derivation,
child strategies).
- `create_label` / `update_label` / `delete_label`.
- `create_automation_rule` / `update_automation_rule` /
`delete_automation_rule` — JsonLogic conditions + category/label
actions, at least one action required.
- `list_labels` — a small **read** tool added so label ids are
discoverable (label/automation tools are unusable without it).
### Guardrails
Write tools never touch bank-sourced data: the existing
`TransactionSource` enum and `Account::isConnected()` are the barriers,
reused not reinvented. There is no server-side write confirmation
(client-controlled, accepted decision) — hence `#[IsDestructive]`.
### Token scope
`StoreMcpTokenRequest` re-adds `scope` (`read` | `read_write`); the
controller grants `['mcp:read']` or `['mcp:read', 'mcp:write']`. The
settings page gets its scope selector back with honest copy (new strings
added to `lang/es.json`). The `/mcp` route stays gated on
`abilities:mcp:read` — any MCP token can connect and read; the per-tool
`mcp:write` check is what blocks writes.
### Tests
Happy path + guardrail failures for every write tool, the
read-only-token rejection (via a real read-only PAT so the `tokenCan`
gate runs exactly as over HTTP), cross-user isolation, the inherited Pro
gate, and read/read_write scope validation.
### Notes
- `AutomationRule::labels()` gained a generic return annotation (needed
for larastan level 5 on the new label mapping).
### Verification
- `vendor/bin/pint --test` ✅
- `vendor/bin/phpstan analyse` (larastan level 5) — 0 errors ✅
- `php artisan test tests/Feature/Mcp
tests/Feature/Settings/McpTokenTest.php
tests/Feature/LocalizationTest.php` ✅
- `prettier --check` / `eslint` on `settings/mcp.tsx` ✅
Víctor Falcón