diff --git a/package-lock.json b/package-lock.json
index 160a6b3..6923b6f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -8,6 +8,8 @@
       "name": "please-prototype",
       "version": "0.0.0",
       "dependencies": {
+        "@matt.kantor/either": "^1.0.0",
+        "@matt.kantor/option": "^1.0.0",
         "kleur": "^4.1.5"
       },
       "bin": {
@@ -18,6 +20,36 @@
         "typescript": "^5.6.2"
       }
     },
+    "node_modules/@matt.kantor/either": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/@matt.kantor/either/-/either-1.0.0.tgz",
+      "integrity": "sha512-Abvg2BkwpQKUIAN5wSnTheBTcNR4dWeRS6E3j6Ra9NbftMfF+fTPtdNGDrtaRT3lTfGnkbhELeLGwd3iokHlpA==",
+      "license": "MIT",
+      "dependencies": {
+        "@matt.kantor/either-tag-symbol": "*"
+      }
+    },
+    "node_modules/@matt.kantor/either-tag-symbol": {
+      "version": "9007199254740991.9007199254740991.9007199254740991",
+      "resolved": "https://registry.npmjs.org/@matt.kantor/either-tag-symbol/-/either-tag-symbol-9007199254740991.9007199254740991.9007199254740991.tgz",
+      "integrity": "sha512-gcsznH1E+z2Or7+bdt3DgvXLgUajDM/zUvS5cmLDIOeYQkeveZTlYnY9dS1Zp6tZU5jQEvd1zUOeYfJhVYa5eA==",
+      "license": "MIT"
+    },
+    "node_modules/@matt.kantor/option": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/@matt.kantor/option/-/option-1.0.0.tgz",
+      "integrity": "sha512-EzMyjqjQ9L+s4KLBLrMRooZlJSz3cj1sK9rRHz7ZfPCt0GJak4ZkARTimSzkS2R6wEaOvJXJH7frlf/y0kHt0g==",
+      "license": "MIT",
+      "dependencies": {
+        "@matt.kantor/option-tag-symbol": "*"
+      }
+    },
+    "node_modules/@matt.kantor/option-tag-symbol": {
+      "version": "9007199254740991.9007199254740991.9007199254740991",
+      "resolved": "https://registry.npmjs.org/@matt.kantor/option-tag-symbol/-/option-tag-symbol-9007199254740991.9007199254740991.9007199254740991.tgz",
+      "integrity": "sha512-SfSHY47RmrQn7Dm6L9Tx4bmUzef4xDmOcQeFtgK5e/3NG/oWzNB6vZkDyBy7rDiBgk5o2Z99HutcEvDX9xTrfg==",
+      "license": "MIT"
+    },
     "node_modules/@types/node": {
       "version": "22.7.8",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-22.7.8.tgz",
diff --git a/package.json b/package.json
index 099d42e..1bde3e2 100644
--- a/package.json
+++ b/package.json
@@ -19,6 +19,8 @@
     "typescript": "^5.6.2"
   },
   "dependencies": {
+    "@matt.kantor/either": "^1.0.0",
+    "@matt.kantor/option": "^1.0.0",
     "kleur": "^4.1.5"
   }
 }
diff --git a/src/adts.ts b/src/adts.ts
deleted file mode 100644
index e34e68a..0000000
--- a/src/adts.ts
+++ /dev/null
@@ -1,9 +0,0 @@
-import * as eitherUtilities from './adts/either-utilities.js'
-import * as eitherAdt from './adts/either.js'
-import * as optionUtilities from './adts/option-utilities.js'
-import * as optionAdt from './adts/option.js'
-
-export type { Either } from './adts/either.js'
-export type { Option } from './adts/option.js'
-export const either = { ...eitherAdt, ...eitherUtilities }
-export const option = { ...optionAdt, ...optionUtilities }
diff --git a/src/adts/either-utilities.ts b/src/adts/either-utilities.ts
deleted file mode 100644
index 91edf79..0000000
--- a/src/adts/either-utilities.ts
+++ /dev/null
@@ -1,43 +0,0 @@
-import { makeLeft, makeRight, match, type Either, type Left } from './either.js'
-
-export const flatMap = <LeftValue, RightValue, NewLeftValue, NewRightValue>(
-  either: Either<LeftValue, RightValue>,
-  f: (value: RightValue) => Either<NewLeftValue, NewRightValue>,
-): Either<LeftValue | NewLeftValue, NewRightValue> =>
-  match(either, {
-    left: makeLeft,
-    right: f,
-  })
-
-export const isLeft = (
-  either: Either<unknown, unknown>,
-): either is Left<unknown> =>
-  match(either, { left: _ => true, right: _ => false })
-
-export const map = <LeftValue, RightValue, NewRightValue>(
-  either: Either<LeftValue, RightValue>,
-  f: (value: RightValue) => NewRightValue,
-): Either<LeftValue, NewRightValue> =>
-  match(either, {
-    left: makeLeft,
-    right: value => makeRight(f(value)),
-  })
-
-export const mapLeft = <LeftValue, RightValue, NewLeftValue>(
-  either: Either<LeftValue, RightValue>,
-  f: (value: LeftValue) => NewLeftValue,
-): Either<NewLeftValue, RightValue> =>
-  match(either, {
-    left: value => makeLeft(f(value)),
-    right: makeRight,
-  })
-
-export const tryCatch = <RightValue>(
-  operation: () => RightValue,
-): Either<unknown, RightValue> => {
-  try {
-    return makeRight(operation())
-  } catch (error) {
-    return makeLeft(error)
-  }
-}
diff --git a/src/adts/either.ts b/src/adts/either.ts
deleted file mode 100644
index 7938490..0000000
--- a/src/adts/either.ts
+++ /dev/null
@@ -1,37 +0,0 @@
-const eitherTag = Symbol('either')
-export type Either<LeftValue, RightValue> = Right<RightValue> | Left<LeftValue>
-
-export type Left<Value> = {
-  readonly [eitherTag]: 'left'
-  readonly value: Value
-}
-
-export type Right<Value> = {
-  readonly [eitherTag]: 'right'
-  readonly value: Value
-}
-
-export const makeLeft = <const Value>(value: Value): Left<Value> => ({
-  [eitherTag]: 'left',
-  value,
-})
-
-export const makeRight = <const Value>(value: Value): Right<Value> => ({
-  [eitherTag]: 'right',
-  value,
-})
-
-export const match = <LeftValue, RightValue, LeftResult, RightResult>(
-  adt: Either<LeftValue, RightValue>,
-  cases: {
-    left: (value: LeftValue) => LeftResult
-    right: (value: RightValue) => RightResult
-  },
-): LeftResult | RightResult => {
-  switch (adt[eitherTag]) {
-    case 'left':
-      return cases[adt[eitherTag]](adt.value)
-    case 'right':
-      return cases[adt[eitherTag]](adt.value)
-  }
-}
diff --git a/src/adts/option-utilities.ts b/src/adts/option-utilities.ts
deleted file mode 100644
index c816083..0000000
--- a/src/adts/option-utilities.ts
+++ /dev/null
@@ -1,29 +0,0 @@
-import { makeSome, match, none, type None, type Option } from './option.js'
-
-export const filter = <Value, NarrowedValue extends Value>(
-  option: Option<Value>,
-  predicate: (value: Value) => value is NarrowedValue,
-): Option<NarrowedValue> =>
-  flatMap(option, value => fromPredicate(value, predicate))
-
-export const fromPredicate = <InputValue, Value extends InputValue>(
-  value: InputValue,
-  predicate: (value: InputValue) => value is Value,
-): Option<Value> => (predicate(value) ? makeSome(value) : none)
-
-export const flatMap = <Value, NewValue>(
-  option: Option<Value>,
-  f: (value: Value) => Option<NewValue>,
-): Option<NewValue> => match(option, { none: () => none, some: f })
-
-export const isNone = (option: Option<unknown>): option is None =>
-  match(option, { none: () => true, some: _ => false })
-
-export const map = <Value, NewValue>(
-  option: Option<Value>,
-  f: (value: Value) => NewValue,
-): Option<NewValue> =>
-  match(option, {
-    none: (): Option<NewValue> => none,
-    some: value => makeSome(f(value)),
-  })
diff --git a/src/adts/option.ts b/src/adts/option.ts
deleted file mode 100644
index 24dede1..0000000
--- a/src/adts/option.ts
+++ /dev/null
@@ -1,33 +0,0 @@
-const optionTag = Symbol('option')
-export type Option<Value> = None | Some<Value>
-
-export type None = {
-  readonly [optionTag]: 'none'
-}
-
-export type Some<Value> = {
-  readonly [optionTag]: 'some'
-  readonly value: Value
-}
-
-export const none: None = { [optionTag]: 'none' }
-
-export const makeSome = <const Value>(value: Value): Some<Value> => ({
-  [optionTag]: 'some',
-  value,
-})
-
-export const match = <Value, NoneResult, SomeResult>(
-  adt: Option<Value>,
-  cases: {
-    none: () => NoneResult
-    some: (value: Value) => SomeResult
-  },
-): NoneResult | SomeResult => {
-  switch (adt[optionTag]) {
-    case 'none':
-      return cases[adt[optionTag]]()
-    case 'some':
-      return cases[adt[optionTag]](adt.value)
-  }
-}
diff --git a/src/end-to-end.test.ts b/src/end-to-end.test.ts
index bbe9acd..ce35da1 100644
--- a/src/end-to-end.test.ts
+++ b/src/end-to-end.test.ts
@@ -1,5 +1,5 @@
+import either, { type Either } from '@matt.kantor/either'
 import assert from 'node:assert'
-import { either, type Either } from './adts.js'
 import { compile } from './language/compiling.js'
 import type { Atom, Molecule } from './language/parsing.js'
 import { parse } from './language/parsing/parser.js'
diff --git a/src/language/cli/input.ts b/src/language/cli/input.ts
index 410ffe4..b0805fd 100644
--- a/src/language/cli/input.ts
+++ b/src/language/cli/input.ts
@@ -1,5 +1,5 @@
+import either, { type Either } from '@matt.kantor/either'
 import { parseArgs } from 'util'
-import { either, type Either } from '../../adts.js'
 import { type JsonValueForbiddingSymbolicKeys } from '../parsing.js'
 
 export type InvalidJsonError = {
diff --git a/src/language/cli/output.ts b/src/language/cli/output.ts
index b4a9c16..3c15219 100644
--- a/src/language/cli/output.ts
+++ b/src/language/cli/output.ts
@@ -1,5 +1,5 @@
+import either, { type Either } from '@matt.kantor/either'
 import { parseArgs } from 'util'
-import { either, type Either } from '../../adts.js'
 import { type SyntaxTree } from '../parsing/syntax-tree.js'
 import { unparse, type Notation } from '../unparsing.js'
 import { prettyJson } from '../unparsing/pretty-json.js'
diff --git a/src/language/cli/please.ts b/src/language/cli/please.ts
index 3fc24fd..cd47d4a 100644
--- a/src/language/cli/please.ts
+++ b/src/language/cli/please.ts
@@ -1,4 +1,4 @@
-import { either, type Either } from '../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
 import { compile } from '../compiling.js'
 import type { Atom, Molecule } from '../parsing.js'
 import { parse } from '../parsing/parser.js'
diff --git a/src/language/compiling/compiler.test.ts b/src/language/compiling/compiler.test.ts
index cd52eb7..7aae3ba 100644
--- a/src/language/compiling/compiler.test.ts
+++ b/src/language/compiling/compiler.test.ts
@@ -1,5 +1,5 @@
+import either, { type Either } from '@matt.kantor/either'
 import assert from 'node:assert'
-import { either, type Either } from '../../adts.js'
 import { withPhantomData } from '../../phantom-data.js'
 import { testCases } from '../../test-utilities.test.js'
 import type { ElaborationError } from '../errors.js'
diff --git a/src/language/compiling/compiler.ts b/src/language/compiling/compiler.ts
index f11a923..490f357 100644
--- a/src/language/compiling/compiler.ts
+++ b/src/language/compiling/compiler.ts
@@ -1,4 +1,4 @@
-import { either, type Either } from '../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
 import type { CompilationError } from '../errors.js'
 import type { JsonValueForbiddingSymbolicKeys } from '../parsing.js'
 import { canonicalize } from '../parsing.js'
diff --git a/src/language/compiling/semantics.test.ts b/src/language/compiling/semantics.test.ts
index 3db73b3..6f4c86d 100644
--- a/src/language/compiling/semantics.test.ts
+++ b/src/language/compiling/semantics.test.ts
@@ -1,5 +1,6 @@
+import either, { type Either } from '@matt.kantor/either'
+import option from '@matt.kantor/option'
 import assert from 'node:assert'
-import { either, option, type Either } from '../../adts.js'
 import { withPhantomData } from '../../phantom-data.js'
 import { testCases } from '../../test-utilities.test.js'
 import type { Writable } from '../../utility-types.js'
diff --git a/src/language/compiling/semantics/keyword-handlers/apply-handler.ts b/src/language/compiling/semantics/keyword-handlers/apply-handler.ts
index 555abc4..2ff3208 100644
--- a/src/language/compiling/semantics/keyword-handlers/apply-handler.ts
+++ b/src/language/compiling/semantics/keyword-handlers/apply-handler.ts
@@ -1,4 +1,4 @@
-import { either, type Either } from '../../../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../../errors.js'
 import {
   asSemanticGraph,
diff --git a/src/language/compiling/semantics/keyword-handlers/check-handler.ts b/src/language/compiling/semantics/keyword-handlers/check-handler.ts
index 556a86b..3c3c93d 100644
--- a/src/language/compiling/semantics/keyword-handlers/check-handler.ts
+++ b/src/language/compiling/semantics/keyword-handlers/check-handler.ts
@@ -1,4 +1,5 @@
-import { either, option, type Either } from '../../../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
+import option from '@matt.kantor/option'
 import type { ElaborationError } from '../../../errors.js'
 import {
   asSemanticGraph,
diff --git a/src/language/compiling/semantics/keyword-handlers/function-handler.ts b/src/language/compiling/semantics/keyword-handlers/function-handler.ts
index e8679f7..141807d 100644
--- a/src/language/compiling/semantics/keyword-handlers/function-handler.ts
+++ b/src/language/compiling/semantics/keyword-handlers/function-handler.ts
@@ -1,4 +1,5 @@
-import { either, option, type Either } from '../../../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
+import option from '@matt.kantor/option'
 import type { ElaborationError } from '../../../errors.js'
 import {
   asSemanticGraph,
diff --git a/src/language/compiling/semantics/keyword-handlers/lookup-handler.ts b/src/language/compiling/semantics/keyword-handlers/lookup-handler.ts
index b62e3ab..a04d733 100644
--- a/src/language/compiling/semantics/keyword-handlers/lookup-handler.ts
+++ b/src/language/compiling/semantics/keyword-handlers/lookup-handler.ts
@@ -1,4 +1,5 @@
-import { either, option, type Either, type Option } from '../../../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
+import option, { type Option } from '@matt.kantor/option'
 import type {
   ElaborationError,
   InvalidExpressionError,
diff --git a/src/language/compiling/semantics/keyword-handlers/runtime-handler.ts b/src/language/compiling/semantics/keyword-handlers/runtime-handler.ts
index ec0ca1d..cca10a2 100644
--- a/src/language/compiling/semantics/keyword-handlers/runtime-handler.ts
+++ b/src/language/compiling/semantics/keyword-handlers/runtime-handler.ts
@@ -1,4 +1,4 @@
-import { either, type Either } from '../../../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../../errors.js'
 import {
   asSemanticGraph,
diff --git a/src/language/compiling/semantics/keyword-handlers/todo-handler.ts b/src/language/compiling/semantics/keyword-handlers/todo-handler.ts
index 96ff8ba..ad48d9e 100644
--- a/src/language/compiling/semantics/keyword-handlers/todo-handler.ts
+++ b/src/language/compiling/semantics/keyword-handlers/todo-handler.ts
@@ -1,4 +1,4 @@
-import { either, type Either } from '../../../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../../errors.js'
 import {
   makeObjectNode,
diff --git a/src/language/parsing/parser.ts b/src/language/parsing/parser.ts
index 93cac67..9e90504 100644
--- a/src/language/parsing/parser.ts
+++ b/src/language/parsing/parser.ts
@@ -1,4 +1,4 @@
-import { either, type Either } from '../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
 import type { ParseError } from '../errors.js'
 import { type SyntaxTree, syntaxTreeParser } from './syntax-tree.js'
 
diff --git a/src/language/parsing/syntax-tree.ts b/src/language/parsing/syntax-tree.ts
index 33a58f7..eca9d37 100644
--- a/src/language/parsing/syntax-tree.ts
+++ b/src/language/parsing/syntax-tree.ts
@@ -1,4 +1,4 @@
-import { option, type Option } from '../../adts.js'
+import option, { type Option } from '@matt.kantor/option'
 import { parser, type Parser } from '../../parsing.js'
 import { withPhantomData, type WithPhantomData } from '../../phantom-data.js'
 import type {
diff --git a/src/language/runtime/evaluator.test.ts b/src/language/runtime/evaluator.test.ts
index cb34ace..80357ab 100644
--- a/src/language/runtime/evaluator.test.ts
+++ b/src/language/runtime/evaluator.test.ts
@@ -1,5 +1,5 @@
+import either, { type Either } from '@matt.kantor/either'
 import assert from 'node:assert'
-import { either, type Either } from '../../adts.js'
 import { withPhantomData } from '../../phantom-data.js'
 import { testCases } from '../../test-utilities.test.js'
 import type { ElaborationError } from '../errors.js'
diff --git a/src/language/runtime/evaluator.ts b/src/language/runtime/evaluator.ts
index ecb63e7..cd7e8c7 100644
--- a/src/language/runtime/evaluator.ts
+++ b/src/language/runtime/evaluator.ts
@@ -1,4 +1,4 @@
-import { either, type Either } from '../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
 import type { RuntimeError } from '../errors.js'
 import type { JsonValueForbiddingSymbolicKeys } from '../parsing.js'
 import { canonicalize } from '../parsing.js'
diff --git a/src/language/runtime/keywords.ts b/src/language/runtime/keywords.ts
index 65ee21e..27a8110 100644
--- a/src/language/runtime/keywords.ts
+++ b/src/language/runtime/keywords.ts
@@ -1,5 +1,6 @@
+import either from '@matt.kantor/either'
+import option, { type Option } from '@matt.kantor/option'
 import { parseArgs } from 'util'
-import { either, option, type Option } from '../../adts.js'
 import { writeOutput } from '../cli/output.js'
 import { keywordHandlers as compilerKeywordHandlers } from '../compiling.js'
 import type { Atom } from '../parsing.js'
diff --git a/src/language/semantics/expression-elaboration.ts b/src/language/semantics/expression-elaboration.ts
index dd23586..1214f29 100644
--- a/src/language/semantics/expression-elaboration.ts
+++ b/src/language/semantics/expression-elaboration.ts
@@ -1,4 +1,5 @@
-import { either, option, type Either } from '../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
+import option from '@matt.kantor/option'
 import { withPhantomData, type WithPhantomData } from '../../phantom-data.js'
 import type { Writable } from '../../utility-types.js'
 import type { ElaborationError, InvalidSyntaxTreeError } from '../errors.js'
@@ -158,23 +159,20 @@ const handleObjectNodeWhichMayBeAExpression = (
   context: ExpressionContext,
 ): Either<ElaborationError, SemanticGraph> => {
   const { 0: possibleKeyword, ...possibleArguments } = node
-  return option.match(option.fromPredicate(possibleKeyword, isKeyword), {
-    none: () =>
-      /^@[^@]/.test(possibleKeyword)
-        ? either.makeLeft({
-            kind: 'unknownKeyword',
-            message: `unknown keyword: \`${possibleKeyword}\``,
-          })
-        : either.makeRight({
-            ...node,
-            0: unescapeKeywordSigil(possibleKeyword),
-          }),
-    some: keyword =>
-      context.keywordHandlers[keyword](
-        makeObjectNode({ ...possibleArguments, 0: keyword }),
+  return isKeyword(possibleKeyword)
+    ? context.keywordHandlers[possibleKeyword](
+        makeObjectNode({ ...possibleArguments, 0: possibleKeyword }),
         context,
-      ),
-  })
+      )
+    : /^@[^@]/.test(possibleKeyword)
+    ? either.makeLeft({
+        kind: 'unknownKeyword',
+        message: `unknown keyword: \`${possibleKeyword}\``,
+      })
+    : either.makeRight({
+        ...node,
+        0: unescapeKeywordSigil(possibleKeyword),
+      })
 }
 
 const handleAtomWhichMayNotBeAKeyword = (
diff --git a/src/language/semantics/expressions/apply-expression.ts b/src/language/semantics/expressions/apply-expression.ts
index b7acecd..dc62309 100644
--- a/src/language/semantics/expressions/apply-expression.ts
+++ b/src/language/semantics/expressions/apply-expression.ts
@@ -1,4 +1,4 @@
-import { either, type Either } from '../../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../errors.js'
 import type { Molecule } from '../../parsing.js'
 import { isExpression } from '../expression.js'
diff --git a/src/language/semantics/expressions/check-expression.ts b/src/language/semantics/expressions/check-expression.ts
index d7d33f8..4af79b3 100644
--- a/src/language/semantics/expressions/check-expression.ts
+++ b/src/language/semantics/expressions/check-expression.ts
@@ -1,4 +1,4 @@
-import { either, type Either } from '../../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../errors.js'
 import type { Molecule } from '../../parsing.js'
 import { isExpression } from '../expression.js'
diff --git a/src/language/semantics/expressions/expression-utilities.ts b/src/language/semantics/expressions/expression-utilities.ts
index 5ebb41b..4edaed9 100644
--- a/src/language/semantics/expressions/expression-utilities.ts
+++ b/src/language/semantics/expressions/expression-utilities.ts
@@ -1,4 +1,5 @@
-import { either, option, type Either, type Option } from '../../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
+import option, { type Option } from '@matt.kantor/option'
 import type { ElaborationError } from '../../errors.js'
 import type { Atom, Molecule } from '../../parsing.js'
 import type { ExpressionContext } from '../expression-elaboration.js'
diff --git a/src/language/semantics/expressions/function-expression.ts b/src/language/semantics/expressions/function-expression.ts
index bbf802e..96fd5d4 100644
--- a/src/language/semantics/expressions/function-expression.ts
+++ b/src/language/semantics/expressions/function-expression.ts
@@ -1,4 +1,4 @@
-import { either, type Either } from '../../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../errors.js'
 import type { Atom, Molecule } from '../../parsing.js'
 import { isExpression } from '../expression.js'
diff --git a/src/language/semantics/expressions/lookup-expression.ts b/src/language/semantics/expressions/lookup-expression.ts
index 9acf0b0..241ddb6 100644
--- a/src/language/semantics/expressions/lookup-expression.ts
+++ b/src/language/semantics/expressions/lookup-expression.ts
@@ -1,4 +1,4 @@
-import { either, type Either } from '../../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError, InvalidExpressionError } from '../../errors.js'
 import type { Molecule } from '../../parsing.js'
 import { isExpression } from '../expression.js'
diff --git a/src/language/semantics/expressions/runtime-expression.ts b/src/language/semantics/expressions/runtime-expression.ts
index d1edffc..f9ccf09 100644
--- a/src/language/semantics/expressions/runtime-expression.ts
+++ b/src/language/semantics/expressions/runtime-expression.ts
@@ -1,4 +1,4 @@
-import { either, type Either } from '../../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
 import type { ElaborationError } from '../../errors.js'
 import type { Molecule } from '../../parsing.js'
 import { isExpression } from '../expression.js'
diff --git a/src/language/semantics/function-node.ts b/src/language/semantics/function-node.ts
index 0016b7b..5b0d506 100644
--- a/src/language/semantics/function-node.ts
+++ b/src/language/semantics/function-node.ts
@@ -1,4 +1,5 @@
-import { either, type Either, type Option } from '../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
+import { type Option } from '@matt.kantor/option'
 import type { Writable } from '../../utility-types.js'
 import type {
   DependencyUnavailable,
diff --git a/src/language/semantics/key-path.ts b/src/language/semantics/key-path.ts
index d35109f..6c2743c 100644
--- a/src/language/semantics/key-path.ts
+++ b/src/language/semantics/key-path.ts
@@ -1,4 +1,4 @@
-import { either } from '../../adts.js'
+import either from '@matt.kantor/either'
 import type { Atom, Molecule } from '../parsing.js'
 import { unparse } from '../unparsing.js'
 import { inlinePlz } from '../unparsing/inline-plz.js'
diff --git a/src/language/semantics/object-node.ts b/src/language/semantics/object-node.ts
index 41f8be3..7f554d7 100644
--- a/src/language/semantics/object-node.ts
+++ b/src/language/semantics/object-node.ts
@@ -1,4 +1,5 @@
-import { either, option, type Either, type Option } from '../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
+import option, { type Option } from '@matt.kantor/option'
 import type { Writable } from '../../utility-types.js'
 import type { UnserializableValueError } from '../errors.js'
 import type { Atom, Molecule } from '../parsing.js'
diff --git a/src/language/semantics/prelude.ts b/src/language/semantics/prelude.ts
index ba016ea..dd22c1e 100644
--- a/src/language/semantics/prelude.ts
+++ b/src/language/semantics/prelude.ts
@@ -1,4 +1,5 @@
-import { either, option, type Either } from '../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
+import option from '@matt.kantor/option'
 import type { DependencyUnavailable, Panic } from '../errors.js'
 import type { Atom } from '../parsing.js'
 import { isFunctionNode, makeFunctionNode } from './function-node.js'
diff --git a/src/language/semantics/semantic-graph.ts b/src/language/semantics/semantic-graph.ts
index 990ca89..3787bb8 100644
--- a/src/language/semantics/semantic-graph.ts
+++ b/src/language/semantics/semantic-graph.ts
@@ -1,4 +1,5 @@
-import { either, option, type Either, type Option } from '../../adts.js'
+import either, { type Either } from '@matt.kantor/either'
+import option, { type Option } from '@matt.kantor/option'
 import { withPhantomData, type WithPhantomData } from '../../phantom-data.js'
 import type {
   InvalidExpressionError,
diff --git a/src/language/semantics/type-system/prelude-types.ts b/src/language/semantics/type-system/prelude-types.ts
index 23e64a3..606bfa6 100644
--- a/src/language/semantics/type-system/prelude-types.ts
+++ b/src/language/semantics/type-system/prelude-types.ts
@@ -1,4 +1,4 @@
-import { option as optionAdt } from '../../../adts.js'
+import optionAdt from '@matt.kantor/option'
 import {
   makeFunctionType,
   makeObjectType,
diff --git a/src/language/semantics/type-system/type-formats.ts b/src/language/semantics/type-system/type-formats.ts
index 070a6a7..f2373dc 100644
--- a/src/language/semantics/type-system/type-formats.ts
+++ b/src/language/semantics/type-system/type-formats.ts
@@ -1,5 +1,5 @@
-import { option } from '../../../adts.js'
-import type { None, Some } from '../../../adts/option.js'
+import type { None, Some } from '@matt.kantor/option'
+import option from '@matt.kantor/option'
 import type { Atom } from '../../parsing.js'
 
 export type FunctionType = {
diff --git a/src/language/unparsing.ts b/src/language/unparsing.ts
index 5a31b51..0414312 100644
--- a/src/language/unparsing.ts
+++ b/src/language/unparsing.ts
@@ -1,4 +1,4 @@
-import type { Either } from '../adts.js'
+import type { Either } from '@matt.kantor/either'
 import type { UnserializableValueError } from './errors.js'
 import type { Atom, Molecule } from './parsing.js'
 import type { Notation } from './unparsing/unparsing-utilities.js'
diff --git a/src/language/unparsing/inline-plz.ts b/src/language/unparsing/inline-plz.ts
index 4d936c5..04f6687 100644
--- a/src/language/unparsing/inline-plz.ts
+++ b/src/language/unparsing/inline-plz.ts
@@ -1,6 +1,6 @@
+import type { Right } from '@matt.kantor/either'
+import either, { type Either } from '@matt.kantor/either'
 import kleur from 'kleur'
-import { either, type Either } from '../../adts.js'
-import type { Right } from '../../adts/either.js'
 import type { UnserializableValueError } from '../errors.js'
 import type { Atom, Molecule } from '../parsing.js'
 import { unquotedAtomParser } from '../parsing/atom.js'
diff --git a/src/language/unparsing/pretty-json.ts b/src/language/unparsing/pretty-json.ts
index 61e6946..81f372f 100644
--- a/src/language/unparsing/pretty-json.ts
+++ b/src/language/unparsing/pretty-json.ts
@@ -1,6 +1,6 @@
+import type { Right } from '@matt.kantor/either'
+import either from '@matt.kantor/either'
 import kleur from 'kleur'
-import { either } from '../../adts.js'
-import type { Right } from '../../adts/either.js'
 import type { Atom, Molecule } from '../parsing.js'
 import { indent, type Notation } from './unparsing-utilities.js'
 
diff --git a/src/language/unparsing/pretty-plz.ts b/src/language/unparsing/pretty-plz.ts
index ea961b9..51dbeaa 100644
--- a/src/language/unparsing/pretty-plz.ts
+++ b/src/language/unparsing/pretty-plz.ts
@@ -1,6 +1,6 @@
+import type { Right } from '@matt.kantor/either'
+import either, { type Either } from '@matt.kantor/either'
 import kleur from 'kleur'
-import { either, type Either } from '../../adts.js'
-import type { Right } from '../../adts/either.js'
 import type { UnserializableValueError } from '../errors.js'
 import type { Atom, Molecule } from '../parsing.js'
 import { unquotedAtomParser } from '../parsing/atom.js'
diff --git a/src/language/unparsing/unparsing-utilities.ts b/src/language/unparsing/unparsing-utilities.ts
index ba0cebe..654e4be 100644
--- a/src/language/unparsing/unparsing-utilities.ts
+++ b/src/language/unparsing/unparsing-utilities.ts
@@ -1,4 +1,4 @@
-import { type Either } from '../../adts.js'
+import { type Either } from '@matt.kantor/either'
 import type { UnserializableValueError } from '../errors.js'
 import type { Atom, Molecule } from '../parsing.js'
 
diff --git a/src/parsing/combinators.ts b/src/parsing/combinators.ts
index 7f5a82b..3e40916 100644
--- a/src/parsing/combinators.ts
+++ b/src/parsing/combinators.ts
@@ -1,4 +1,4 @@
-import { either } from '../adts.js'
+import either from '@matt.kantor/either'
 import { nothing } from './constructors.js'
 import type { AlwaysSucceedingParser, Parser, Success } from './parser.js'
 
diff --git a/src/parsing/constructors.ts b/src/parsing/constructors.ts
index d6ebeb4..b761cdc 100644
--- a/src/parsing/constructors.ts
+++ b/src/parsing/constructors.ts
@@ -1,4 +1,4 @@
-import { either } from '../adts.js'
+import either from '@matt.kantor/either'
 import type { AlwaysSucceedingParser, Parser } from './parser.js'
 
 export const anySingleCharacter: Parser<string> = input => {
diff --git a/src/parsing/parser.ts b/src/parsing/parser.ts
index dac9446..240e776 100644
--- a/src/parsing/parser.ts
+++ b/src/parsing/parser.ts
@@ -1,5 +1,4 @@
-import type { Either } from '../adts.js'
-import type { Right } from '../adts/either.js'
+import type { Either, Right } from '@matt.kantor/either'
 
 export type Success<Output> = {
   readonly remainingInput: string