type-atlas

codex mcp add type-atlas -- npx --yes @type-atlas/mcp@latest

claude mcp add --scope user type-atlas -- npx --yes @type-atlas/mcp@latest

code --add-mcp '{"name":"type-atlas","command":"npx","args":["--yes","@type-atlas/mcp@latest"]}'

{
  "mcpServers": {
    "type-atlas": {
      "command": "npx",
      "args": ["--yes", "@type-atlas/mcp@latest"]
    }
  }
}

tool: List files
workspace: fixtures/ledger
# working tree arranged: currency.ts edited · rounding.ts created · index.ts deleted
directory: packages/money
depth: 2

# answered in 57ms

packages/money/
├  src/ · 3 changed
│  ├  currency.ts · 21 loc · M +2
│  ├  index.ts · D -12
│  ├  money.ts · 58 loc
│  ├  rounding-mode.ts · 15 loc
│  └  rounding.ts · 11 loc · U
├  tests/
│  ├  money.test.ts · 15 loc
│  └  rounding-parity.ts · 15 loc
├  package.json · 19 loc
└  tsconfig.json · 20 loc

tool: Inspect symbol
workspace: fixtures/ledger
file: packages/accounts/src/journal.ts
symbol: Journal

# answered in 49ms

Journal [class] · packages/accounts/src/journal.ts:24:14-24:21 · range 24:1-73:2 · packages/accounts/tsconfig.json

```typescript
class Journal<TMeta = undefined>
```

An append-only journal of balanced entries. `TMeta` carries whatever a
consumer attaches to each entry — an import batch id, an approval trail —
without the journal knowing its shape.

## Callers (4)

packages/accounts/tests/journal.test.ts
├  test("posts a balanced transfer through the overload") callback [function] 5:56-14:2 · calls 6:23-6:30
└  test("refuses an unbalanced entry") callback [function] 16:37-29:2 · calls 17:23-17:30
packages/reports/src/balance.ts
└  balancesAsOf [variable] 23:14-23:26 · range 23:14-51:2 · calls 24:12-24:19
packages/importers/src/csv.ts
└  importStatement [variable] 28:14-28:29 · range 28:14-47:2 · calls 29:12-29:19

## Mentions that are not calls (4 of 9 references · 5 relevant projects searched)

packages/accounts/tests/journal.test.ts:3:25-3:32:  import { credit, debit, Journal, UnbalancedEntryError } from "../src/index.ts";
packages/accounts/src/index.ts:11:22-11:29:  export { type Entry, Journal, UnbalancedEntryError } from "./journal.ts";
packages/reports/src/balance.ts:4:8-4:15:  type Journal,
packages/importers/src/csv.ts:1:10-1:17:  import { Journal, type Entry, credit, debit, type AccountPath } from "@ledger/accounts";

references lists all 9, with paging.

tool: Read files
workspace: fixtures/ledger
file: ["packages/accounts/src/posting.ts","packages/money/src/rounding-mode.ts"]

# answered in 7ms

2 files · 42 lines · 6 folded to signatures, pass fold: false for the bodies

=== packages/accounts/src/posting.ts · 32 lines ===

 1 | import { type Money, negate } from "@ledger/money";
 2 | import type { AccountPath } from "./account.ts";
 3 |
 4 | /**
 5 |  * One side of a journal entry. The discriminant is the bookkeeping side, so
 6 |  * every consumer's switch is checked for exhaustiveness by the compiler.
 7 |  */
 8 | export type Posting =
 9 |   | { readonly side: "debit"; readonly account: AccountPath; readonly amount: Money }
10 |   | { readonly side: "credit"; readonly account: AccountPath; readonly amount: Money };
11 |
12 | export const debit = (account: AccountPath, amount: Money): Posting => ({
13 |   side: "debit",
14 |   account,
15 |   amount,
16 | });
17 |
18 | export const credit = (account: AccountPath, amount: Money): Posting => ({
19 |   side: "credit",
20 |   account,
21 |   amount,
22 | });
23 |
24 | /** A posting's effect on a debit-normal running balance. */
25 | export const signedAmount = (posting: Posting): Money => {
   |   ... 26-31 folded
32 | };

=== packages/money/src/rounding-mode.ts · 15 lines ===

 1 | /** How sub-minor precision resolves when a statement and the books disagree. */
 2 | export enum RoundingMode {
 3 |   HalfUp = "half-up",
 4 |   HalfEven = "half-even",
 5 |   Truncate = "truncate",
 6 | }
 7 |
 8 | /** Per-institution conventions, as observed in their exports. */
 9 | const bankRounding: Readonly<Record<string, RoundingMode>> = {
10 |   "first-national": RoundingMode.HalfEven,
11 |   "harbor-credit": RoundingMode.HalfUp,
12 | };
13 |
14 | export const roundingModeOf = (bank: string): RoundingMode =>
15 |   bankRounding[bank] ?? RoundingMode.HalfEven;

tool: Occurrences
workspace: fixtures/ledger
text: signedAmount

# answered in 12ms

"signedAmount" occurs 12 times in 7 files · 67 files scanned under the workspace · 1 file of declared build output not scanned.

packages/accounts/src/index.ts:12:39 · export { credit, debit, type Posting, signedAmount } from "./posting.ts";
packages/accounts/src/journal.ts
├  3:39  · import { credit, debit, type Posting, signedAmount } from "./posting.ts";
└  52:12 · .map(signedAmount)
packages/accounts/src/posting.ts:25:14 · export const signedAmount = (posting: Posting): Money => {
packages/reconcile/src/drift.ts
├  4:24  · import { type Posting, signedAmount } from "@ledger/accounts";
└  20:37 · const journalTotal = postings.map(signedAmount).reduce((total, amount) => total + amount);
packages/reconcile/src/matching.ts
├  1:55  · // DELIBERATELY BROKEN — the imports for `money` and `signedAmount` are
└  14:20 · const amount = signedAmount(posting);
packages/reports/src/balance.ts
├  6:3   · signedAmount,
└  34:57 · add(own.get(posting.account) ?? zero(currency), signedAmount(posting)),
packages/rules/src/builtin.ts
├  1:10  · import { signedAmount } from "@ledger/accounts";
└  26:12 · .map(signedAmount)

tool: Search code
workspace: fixtures/ledger
query: walking an account up through each of its ancestor accounts
snippetLines: 6

# answered in 20ms

Search: walking an account up through each of its ancestor accounts

5 matches · no identifier to anchor on, so these are ranked by meaning alone

=== 1 · packages/accounts/src/account.ts:21-35 ===

Structure: parentPath
Symbol: parentPath [variable] · selection 21:14-21:24 · range 21:14-24:2

21 | export const parentPath = (path: AccountPath): AccountPath | undefined => {
22 |   const at = path.lastIndexOf(":");
23 |   return at === -1 ? undefined : path.slice(0, at);
24 | };
25 |
26 | /** Every ancestor from root to the account itself: `a`, `a:b`, `a:b:c`. */

=== 2 · packages/reports/src/balance.ts:1-23 ===

Structure: BalanceLine
Symbol: BalanceLine [interface] · selection 11:18-11:29 · range 11:1-16:2

1 | import {
2 |   type AccountPath,
3 |   type Entry,
4 |   type Journal,
5 |   lineage,
6 |   signedAmount,

=== 3 · packages/accounts/src/journal.ts:59-73 ===

Structure: Journal > history
Symbol: history [method] · selection 60:3-60:10 · range 60:3-64:4

59 |   /** Entries touching an account, oldest first. */
60 |   history(account: AccountPath): readonly Entry<TMeta>[] {
61 |     return this.entries.filter((entry) =>
62 |       entry.postings.some((posting) => posting.account === account),
63 |     );
64 |   }

=== 4 · packages/reports/src/statement.ts:1-11 ===

Structure: statementLine
Symbol: statementLine [variable] · selection 8:14-8:27 · range 8:14-11:2

1 | import { type Account, normalBalance } from "@ledger/accounts";
2 | import { format, type Money, negate } from "@ledger/money";
3 |
4 | /**
5 |  * One rendered statement line. The sign follows the account's normal side:
6 |  * a liability holding a credit balance reads as positive on its statement.

=== 5 · packages/accounts/src/posting.ts:1-24 ===

Structure: credit
Symbol: credit [variable] · selection 18:14-18:20 · range 18:14-22:3

1 | import { type Money, negate } from "@ledger/money";
2 | import type { AccountPath } from "./account.ts";
3 |
4 | /**
5 |  * One side of a journal entry. The discriminant is the bookkeeping side, so
6 |  * every consumer's switch is checked for exhaustiveness by the compiler.

tool: Diagnostics
workspace: fixtures/ledger
file: packages/reconcile/src/drift.ts

# answered in 23ms

packages/reconcile/src/drift.ts · 4 problems · packages/reconcile/tsconfig.json

=== packages/reconcile/src/drift.ts ===

error ts(2365) 16:33-16:52 — inside lines.reduce() callback
  Operator '+' cannot be applied to types 'number' and 'Money'.
   14 | /** Statement total, computed by someone who forgot Money is not a number.…
   15 | export const statementTotal = (lines: readonly StatementLine[]): number =>
   16 |   lines.reduce((total, line) => total + line.amount, 0);
      |                                 ^^^^^^^^^^^^^^^^^^^
   17 |
   18 | /** Drift between the journal's view and the bank's view of one day. */

error ts(2365) 20:77-20:91 — inside reduce() callback
  Operator '+' cannot be applied to types 'import("packages/money/src/money").Money' and 'import("packages/money/src/money").Money'.
   18 | /** Drift between the journal's view and the bank's view of one day. */
   19 | export const drift = (postings: readonly Posting[], statement: readonly St…
   20 |   const journalTotal = postings.map(signedAmount).reduce((total, amount) =…
      |                                                                             ^^^^^^^^^^^^^^
   21 |   return format(money(journalTotal - statementTotal(statement), "usd"));
   22 | };

error ts(2345) 21:65-21:70 — inside drift
  Argument of type '"usd"' is not assignable to parameter of type 'Currency'.
   19 | export const drift = (postings: readonly Posting[], statement: readonly St…
   20 |   const journalTotal = postings.map(signedAmount).reduce((total, amount) =…
   21 |   return format(money(journalTotal - statementTotal(statement), "usd"));
      |                                                                 ^^^^^
   22 | };
   23 |

error ts(2362) 21:23-21:35 — inside drift
  The left-hand side of an arithmetic operation must be of type 'any', 'number', 'bigint' or an enum type.
   19 | export const drift = (postings: readonly Posting[], statement: readonly St…
   20 |   const journalTotal = postings.map(signedAmount).reduce((total, amount) =…
   21 |   return format(money(journalTotal - statementTotal(statement), "usd"));
      |                       ^^^^^^^^^^^^
   22 | };
   23 |

tool: Workspace symbols
workspace: fixtures/ledger
file: packages/importers/src/statement-parser.ts
query: Parser

# answered in 100ms

3 symbols matching Parser · 8 projects loaded · packages/importers/tsconfig.json

CsvStatementParser [class] · packages/importers/src/statement-parser.ts:25:1-35:2
FixedWidthStatementParser [class] · packages/importers/src/statement-parser.ts:41:1-64:2
StatementParser [class] · packages/importers/src/statement-parser.ts:7:1-23:2

tool: File references
workspace: fixtures/ledger
file: packages/money/src/money.ts

# answered in 134ms

packages/money/src/money.ts · referenced from 90 places · 6 relevant projects searched · packages/money/tsconfig.json

1-20 of 90 places · pass offset: 20 for the rest

packages/accounts/src/journal.ts
├  1:10  — at module level
└  53:15 — inside post
packages/money/src/index.ts
├  3:3 — at module level
├  4:3 — at module level
└  5:3 — at module level
packages/money/tests/money.test.ts
├  2:10  — at module level
├  2:15  — at module level
├  2:38  — at module level
├  5:10  — inside test("adds amounts of one currency exactly") callback
├  9:16  — inside expect() callback
├  9:67  — inside test("refuses to combine currencies") callback
├  13:10 — inside test("formats major and minor units per currency") callback
└  14:10 — inside test("formats major and minor units per currency") callback
packages/reports/src/balance.ts
├  8:10  — at module level
├  34:9  — inside balancesAsOf
└  41:28 — inside balancesAsOf
packages/reports/src/statement.ts
├  2:10  — at module level
└  10:40 — inside statementLine
packages/rules/src/builtin.ts
├  2:10  — at module level
└  28:58 — inside closedPeriodsBalance

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