diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7feb6a33a..41325bdf2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,6 +23,12 @@ jobs:
       - name: Lint
         run: yarn lint
 
+      - name: Type-check
+        run: yarn typecheck
+
+      - name: Check type-check programs use live source
+        run: yarn tsx bin/check-typecheck-sources.ts
+
   run-tests:
     runs-on: ubuntu-latest
     strategy:
@@ -66,3 +72,24 @@ jobs:
       - name: Build website
         run: yarn build
         working-directory: ./packages/web
+
+  build-playground:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: yarn
+          cache-dependency-path: yarn.lock
+
+      - name: Install dependencies
+        run: yarn install --frozen-lockfile
+
+      - name: Build all packages
+        run: yarn build
+
+      - name: Build playground
+        run: yarn build
+        working-directory: ./packages/playground
diff --git a/bin/check-typecheck-sources.test.ts b/bin/check-typecheck-sources.test.ts
new file mode 100644
index 000000000..ee0bcc684
--- /dev/null
+++ b/bin/check-typecheck-sources.test.ts
@@ -0,0 +1,36 @@
+import { describe, expect, it } from "vitest";
+import { builtFiles } from "./check-typecheck-sources.js";
+
+const listing = [
+  "/repo/node_modules/typescript/lib/lib.es2020.d.ts",
+  "/repo/packages/format/src/index.ts",
+  "/repo/packages/pointers/src/read.ts",
+  "/repo/node_modules/@types/node/index.d.ts",
+  "",
+];
+
+describe("builtFiles", () => {
+  it("accepts source files and third-party declarations", () => {
+    expect(builtFiles(listing.join("\n"))).toEqual([]);
+  });
+
+  it("reports a sibling package's built declarations", () => {
+    const stdout = [
+      ...listing,
+      "/repo/packages/format/dist/src/index.d.ts",
+    ].join("\n");
+    expect(builtFiles(stdout)).toEqual([
+      "/repo/packages/format/dist/src/index.d.ts",
+    ]);
+  });
+
+  it("reports declarations reached through node_modules/@ethdebug", () => {
+    const stdout = [
+      ...listing,
+      "/repo/node_modules/@ethdebug/format/dist/src/index.d.ts",
+    ].join("\n");
+    expect(builtFiles(stdout)).toEqual([
+      "/repo/node_modules/@ethdebug/format/dist/src/index.d.ts",
+    ]);
+  });
+});
diff --git a/bin/check-typecheck-sources.ts b/bin/check-typecheck-sources.ts
new file mode 100644
index 000000000..fccc41bf7
--- /dev/null
+++ b/bin/check-typecheck-sources.ts
@@ -0,0 +1,52 @@
+import { execFileSync } from "node:child_process";
+import { existsSync } from "node:fs";
+import { join } from "node:path";
+import { fileURLToPath, pathToFileURL } from "node:url";
+import { readWorkspaces } from "./publish-tagged.js";
+
+const built = [/packages\/[^/]+\/dist\//, /node_modules\/@ethdebug\//];
+
+export function builtFiles(stdout: string): string[] {
+  return stdout
+    .split("\n")
+    .map((line) => line.trim())
+    .filter((line) => line.length > 0 && built.some((re) => re.test(line)));
+}
+
+function tsc(root: string, packageDir: string): string {
+  const local = join(packageDir, "node_modules", ".bin", "tsc");
+  return existsSync(local) ? local : join(root, "node_modules", ".bin", "tsc");
+}
+
+function listFiles(root: string, packageDir: string): string {
+  return execFileSync(
+    tsc(root, packageDir),
+    ["-p", "tsconfig.typecheck.json", "--listFiles", "--noEmit"],
+    { cwd: packageDir, encoding: "utf8", stdio: ["ignore", "pipe", "inherit"] },
+  );
+}
+
+function main(): number {
+  const root = fileURLToPath(new URL("..", import.meta.url));
+  let failed = false;
+  for (const workspace of readWorkspaces(root)) {
+    if (!existsSync(join(workspace.dir, "tsconfig.typecheck.json"))) {
+      continue;
+    }
+    const bad = builtFiles(listFiles(root, workspace.dir));
+    if (bad.length > 0) {
+      failed = true;
+      console.error(`${workspace.name}: type-check reads built declarations:`);
+      for (const path of bad) {
+        console.error(`  ${path}`);
+      }
+    } else {
+      console.log(`${workspace.name}: ok`);
+    }
+  }
+  return failed ? 1 : 0;
+}
+
+if (import.meta.url === pathToFileURL(process.argv[1]).href) {
+  process.exit(main());
+}
diff --git a/bin/start b/bin/start
index ffd64a77b..05b20cc07 100755
--- a/bin/start
+++ b/bin/start
@@ -1,4 +1,4 @@
-#!/usr/bin/env sh
+#!/usr/bin/env bash
 
 # Check if the --no-open flag is provided
 if [[ " $* " == *" --no-open "* ]]; then
@@ -10,11 +10,14 @@ else
 fi
 
 # Run the commands with concurrently
-concurrently --names=format,pointers,evm,bugc,programs-react,playground,web,tests \
+concurrently \
+  --names=format,pointers,evm,bugc,bugc-react,pointers-react,programs-react,playground,web,tests \
   "cd ./packages/format && yarn watch" \
   "cd ./packages/pointers && yarn watch" \
   "cd ./packages/evm && yarn watch" \
   "cd ./packages/bugc && yarn watch" \
+  "cd ./packages/bugc-react && yarn watch" \
+  "cd ./packages/pointers-react && yarn watch" \
   "cd ./packages/programs-react && yarn watch" \
   "cd ./packages/playground && yarn watch" \
   "cd ./packages/web && yarn start $DOCUSAURUS_NO_OPEN" \
diff --git a/package.json b/package.json
index 1be098745..ca4eb2efe 100644
--- a/package.json
+++ b/package.json
@@ -5,8 +5,9 @@
     "packages/*"
   ],
   "scripts": {
-    "build": "yarn lerna run build --no-private",
+    "build": "yarn lerna run build --ignore @ethdebug/format-web --ignore @ethdebug/bug-playground",
     "bundle": "tsx ./bin/bundle-schema.ts",
+    "typecheck": "yarn lerna run typecheck --ignore @ethdebug/format-web --ignore @ethdebug/bug-playground",
     "test": "vitest run",
     "test:coverage": "vitest run --coverage",
     "start": "./bin/start",
diff --git a/packages/bugc-react/package.json b/packages/bugc-react/package.json
index 19efeedd6..35c5225f1 100644
--- a/packages/bugc-react/package.json
+++ b/packages/bugc-react/package.json
@@ -46,7 +46,8 @@
   "scripts": {
     "build": "rm -rf dist && tsc --build tsconfig.build.json && copyfiles -u 1 \"src/**/*.css\" dist/src",
     "prepare": "yarn build",
-    "watch": "tsc --watch --preserveWatchOutput",
+    "typecheck": "tsc -p tsconfig.typecheck.json",
+    "watch": "copyfiles -u 1 \"src/**/*.css\" dist/src && concurrently --names=tsc,css \"tsc --watch --preserveWatchOutput\" \"nodemon --watch src -e css --exec 'copyfiles -u 1 \\\"src/**/*.css\\\" dist/src'\"",
     "test": "vitest run"
   },
   "dependencies": {
@@ -58,7 +59,9 @@
     "@types/dagre": "^0.7.52",
     "@types/react": "^18.2.43",
     "@types/react-dom": "^18.2.17",
+    "concurrently": "^8.2.2",
     "jsdom": "^26.0.0",
+    "nodemon": "^3.1.11",
     "react": "^18.2.0",
     "react-dom": "^18.2.0",
     "typescript": "^5.0.0",
diff --git a/packages/bugc-react/tsconfig.typecheck.json b/packages/bugc-react/tsconfig.typecheck.json
new file mode 100644
index 000000000..2d774f1e3
--- /dev/null
+++ b/packages/bugc-react/tsconfig.typecheck.json
@@ -0,0 +1,16 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "noEmit": true,
+    "composite": false,
+    "incremental": false,
+    "rootDir": "../..",
+    "paths": {
+      "@ethdebug/bugc": ["../bugc/src/index.ts"],
+      "@ethdebug/evm": ["../evm/src/index.ts"],
+      "@ethdebug/format": ["../format/src/index.ts"],
+      "@ethdebug/pointers": ["../pointers/src/index.ts"],
+      "@ethdebug/bugc/examples": ["../bugc/src/examples/index.ts"]
+    }
+  }
+}
diff --git a/packages/bugc/package.json b/packages/bugc/package.json
index 853ea9958..76d5a677b 100644
--- a/packages/bugc/package.json
+++ b/packages/bugc/package.json
@@ -26,44 +26,158 @@
     "bugc": "./dist/bin/bugc.js"
   },
   "imports": {
-    "#ast": "./dist/src/ast/index.js",
-    "#ast/spec": "./dist/src/ast/spec.js",
-    "#ast/visitor": "./dist/src/ast/visitor.js",
-    "#ast/analysis": "./dist/src/ast/analysis/index.js",
-    "#cli": "./dist/src/cli/index.js",
-    "#compiler": "./dist/src/compiler/index.js",
-    "#errors": "./dist/src/errors/index.js",
-    "#evm": "./dist/src/evm/index.js",
-    "#evm/spec": "./dist/src/evm/spec/index.js",
-    "#evm/analysis": "./dist/src/evm/analysis/index.js",
-    "#evmgen": "./dist/src/evmgen/index.js",
-    "#evmgen/analysis": "./dist/src/evmgen/analysis/index.js",
-    "#evmgen/errors": "./dist/src/evmgen/errors.js",
-    "#evmgen/state": "./dist/src/evmgen/state.js",
-    "#evmgen/operations": "./dist/src/evmgen/operations.js",
-    "#evmgen/generation": "./dist/src/evmgen/generation/index.js",
-    "#evmgen/serialize": "./dist/src/evmgen/serialize.js",
-    "#evmgen/pass": "./dist/src/evmgen/pass.js",
-    "#evmgen/program-builder": "./dist/src/evmgen/program-builder.js",
-    "#ir": "./dist/src/ir/index.js",
-    "#ir/spec": "./dist/src/ir/spec/index.js",
-    "#ir/analysis": "./dist/src/ir/analysis/index.js",
-    "#irgen": "./dist/src/irgen/index.js",
-    "#irgen/pass": "./dist/src/irgen/pass.js",
-    "#irgen/errors": "./dist/src/irgen/errors.js",
-    "#irgen/type": "./dist/src/irgen/type.js",
-    "#irgen/generate": "./dist/src/irgen/generate/index.js",
-    "#irgen/debug/variables": "./dist/src/irgen/debug/variables.js",
-    "#optimizer": "./dist/src/optimizer/index.js",
-    "#optimizer/*": "./dist/src/optimizer/*.js",
-    "#parser": "./dist/src/parser/index.js",
-    "#parser/pass": "./dist/src/parser/pass.js",
-    "#result": "./dist/src/result.js",
-    "#typechecker": "./dist/src/typechecker/index.js",
-    "#typechecker/pass": "./dist/src/typechecker/pass.js",
-    "#types": "./dist/src/types/index.js",
-    "#types/analysis": "./dist/src/types/analysis/index.js",
-    "#types/spec": "./dist/src/types/spec.js",
+    "#ast": {
+      "types": "./src/ast/index.ts",
+      "default": "./dist/src/ast/index.js"
+    },
+    "#ast/spec": {
+      "types": "./src/ast/spec.ts",
+      "default": "./dist/src/ast/spec.js"
+    },
+    "#ast/visitor": {
+      "types": "./src/ast/visitor.ts",
+      "default": "./dist/src/ast/visitor.js"
+    },
+    "#ast/analysis": {
+      "types": "./src/ast/analysis/index.ts",
+      "default": "./dist/src/ast/analysis/index.js"
+    },
+    "#cli": {
+      "types": "./src/cli/index.ts",
+      "default": "./dist/src/cli/index.js"
+    },
+    "#compiler": {
+      "types": "./src/compiler/index.ts",
+      "default": "./dist/src/compiler/index.js"
+    },
+    "#errors": {
+      "types": "./src/errors/index.ts",
+      "default": "./dist/src/errors/index.js"
+    },
+    "#evm": {
+      "types": "./src/evm/index.ts",
+      "default": "./dist/src/evm/index.js"
+    },
+    "#evm/spec": {
+      "types": "./src/evm/spec/index.ts",
+      "default": "./dist/src/evm/spec/index.js"
+    },
+    "#evm/analysis": {
+      "types": "./src/evm/analysis/index.ts",
+      "default": "./dist/src/evm/analysis/index.js"
+    },
+    "#evmgen": {
+      "types": "./src/evmgen/index.ts",
+      "default": "./dist/src/evmgen/index.js"
+    },
+    "#evmgen/analysis": {
+      "types": "./src/evmgen/analysis/index.ts",
+      "default": "./dist/src/evmgen/analysis/index.js"
+    },
+    "#evmgen/errors": {
+      "types": "./src/evmgen/errors.ts",
+      "default": "./dist/src/evmgen/errors.js"
+    },
+    "#evmgen/state": {
+      "types": "./src/evmgen/state.ts",
+      "default": "./dist/src/evmgen/state.js"
+    },
+    "#evmgen/operations": {
+      "types": "./src/evmgen/operations.ts",
+      "default": "./dist/src/evmgen/operations.js"
+    },
+    "#evmgen/generation": {
+      "types": "./src/evmgen/generation/index.ts",
+      "default": "./dist/src/evmgen/generation/index.js"
+    },
+    "#evmgen/serialize": {
+      "types": "./src/evmgen/serialize.ts",
+      "default": "./dist/src/evmgen/serialize.js"
+    },
+    "#evmgen/pass": {
+      "types": "./src/evmgen/pass.ts",
+      "default": "./dist/src/evmgen/pass.js"
+    },
+    "#evmgen/program-builder": {
+      "types": "./src/evmgen/program-builder.ts",
+      "default": "./dist/src/evmgen/program-builder.js"
+    },
+    "#ir": {
+      "types": "./src/ir/index.ts",
+      "default": "./dist/src/ir/index.js"
+    },
+    "#ir/spec": {
+      "types": "./src/ir/spec/index.ts",
+      "default": "./dist/src/ir/spec/index.js"
+    },
+    "#ir/analysis": {
+      "types": "./src/ir/analysis/index.ts",
+      "default": "./dist/src/ir/analysis/index.js"
+    },
+    "#irgen": {
+      "types": "./src/irgen/index.ts",
+      "default": "./dist/src/irgen/index.js"
+    },
+    "#irgen/pass": {
+      "types": "./src/irgen/pass.ts",
+      "default": "./dist/src/irgen/pass.js"
+    },
+    "#irgen/errors": {
+      "types": "./src/irgen/errors.ts",
+      "default": "./dist/src/irgen/errors.js"
+    },
+    "#irgen/type": {
+      "types": "./src/irgen/type.ts",
+      "default": "./dist/src/irgen/type.js"
+    },
+    "#irgen/generate": {
+      "types": "./src/irgen/generate/index.ts",
+      "default": "./dist/src/irgen/generate/index.js"
+    },
+    "#irgen/debug/variables": {
+      "types": "./src/irgen/debug/variables.ts",
+      "default": "./dist/src/irgen/debug/variables.js"
+    },
+    "#optimizer": {
+      "types": "./src/optimizer/index.ts",
+      "default": "./dist/src/optimizer/index.js"
+    },
+    "#optimizer/*": {
+      "types": "./src/optimizer/*.ts",
+      "default": "./dist/src/optimizer/*.js"
+    },
+    "#parser": {
+      "types": "./src/parser/index.ts",
+      "default": "./dist/src/parser/index.js"
+    },
+    "#parser/pass": {
+      "types": "./src/parser/pass.ts",
+      "default": "./dist/src/parser/pass.js"
+    },
+    "#result": {
+      "types": "./src/result.ts",
+      "default": "./dist/src/result.js"
+    },
+    "#typechecker": {
+      "types": "./src/typechecker/index.ts",
+      "default": "./dist/src/typechecker/index.js"
+    },
+    "#typechecker/pass": {
+      "types": "./src/typechecker/pass.ts",
+      "default": "./dist/src/typechecker/pass.js"
+    },
+    "#types": {
+      "types": "./src/types/index.ts",
+      "default": "./dist/src/types/index.js"
+    },
+    "#types/analysis": {
+      "types": "./src/types/analysis/index.ts",
+      "default": "./dist/src/types/analysis/index.js"
+    },
+    "#types/spec": {
+      "types": "./src/types/spec.ts",
+      "default": "./dist/src/types/spec.js"
+    },
     "#test/*": "./test/*.ts"
   },
   "scripts": {
@@ -75,7 +189,7 @@
     "test:watch": "vitest",
     "test:coverage": "vitest run --coverage",
     "lint": "eslint src bin --ext .ts",
-    "typecheck": "tsc --noEmit",
+    "typecheck": "tsc -p tsconfig.typecheck.json",
     "format": "prettier --write \"src/**/*.ts\"",
     "format:check": "prettier --check \"src/**/*.ts\"",
     "prepare": "yarn build"
diff --git a/packages/bugc/tsconfig.typecheck.json b/packages/bugc/tsconfig.typecheck.json
new file mode 100644
index 000000000..ef688383c
--- /dev/null
+++ b/packages/bugc/tsconfig.typecheck.json
@@ -0,0 +1,14 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "noEmit": true,
+    "composite": false,
+    "incremental": false,
+    "rootDir": "../..",
+    "paths": {
+      "@ethdebug/evm": ["../evm/src/index.ts"],
+      "@ethdebug/format": ["../format/src/index.ts"],
+      "@ethdebug/pointers": ["../pointers/src/index.ts"]
+    }
+  }
+}
diff --git a/packages/conformance/package.json b/packages/conformance/package.json
index e2e315626..3eb70388e 100644
--- a/packages/conformance/package.json
+++ b/packages/conformance/package.json
@@ -38,8 +38,9 @@
     }
   },
   "scripts": {
-    "prepare": "tsc",
-    "build": "tsc",
+    "prepare": "yarn build",
+    "build": "rm -rf dist && tsc",
+    "typecheck": "tsc -p tsconfig.typecheck.json",
     "test": "vitest run",
     "test:external": "vitest run --no-file-parallelism --maxWorkers=1"
   },
diff --git a/packages/conformance/tsconfig.typecheck.json b/packages/conformance/tsconfig.typecheck.json
new file mode 100644
index 000000000..3d9d53868
--- /dev/null
+++ b/packages/conformance/tsconfig.typecheck.json
@@ -0,0 +1,15 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "noEmit": true,
+    "composite": false,
+    "incremental": false,
+    "rootDir": "../..",
+    "paths": {
+      "@ethdebug/bugc": ["../bugc/src/index.ts"],
+      "@ethdebug/evm": ["../evm/src/index.ts"],
+      "@ethdebug/format": ["../format/src/index.ts"],
+      "@ethdebug/pointers": ["../pointers/src/index.ts"]
+    }
+  }
+}
diff --git a/packages/evm/package.json b/packages/evm/package.json
index 0392246a3..540777384 100644
--- a/packages/evm/package.json
+++ b/packages/evm/package.json
@@ -35,6 +35,7 @@
   "scripts": {
     "build": "rm -rf dist && tsc --build tsconfig.build.json",
     "prepare": "yarn build",
+    "typecheck": "tsc -p tsconfig.typecheck.json",
     "watch": "tsc --watch --preserveWatchOutput",
     "test": "vitest run"
   },
diff --git a/packages/evm/tsconfig.typecheck.json b/packages/evm/tsconfig.typecheck.json
new file mode 100644
index 000000000..6e118cf76
--- /dev/null
+++ b/packages/evm/tsconfig.typecheck.json
@@ -0,0 +1,13 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "noEmit": true,
+    "composite": false,
+    "incremental": false,
+    "rootDir": "../..",
+    "paths": {
+      "@ethdebug/format": ["../format/src/index.ts"],
+      "@ethdebug/pointers": ["../pointers/src/index.ts"]
+    }
+  }
+}
diff --git a/packages/format/package.json b/packages/format/package.json
index 488429ff5..3867b2232 100644
--- a/packages/format/package.json
+++ b/packages/format/package.json
@@ -57,6 +57,7 @@
     "build": "yarn prepare:yamls && rm -rf dist && tsc --build tsconfig.build.json",
     "prepare": "yarn build",
     "clean": "rm -rf dist && rm src/schemas/yamls.ts",
+    "typecheck": "tsc -p tsconfig.typecheck.json",
     "test": "vitest",
     "watch:typescript": "tsc --watch",
     "watch:schemas": "nodemon --watch ../../schemas -e 'yaml' --exec 'yarn prepare:yamls'",
diff --git a/packages/format/tsconfig.typecheck.json b/packages/format/tsconfig.typecheck.json
new file mode 100644
index 000000000..ee7871ef0
--- /dev/null
+++ b/packages/format/tsconfig.typecheck.json
@@ -0,0 +1,8 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "noEmit": true,
+    "composite": false,
+    "incremental": false
+  }
+}
diff --git a/packages/pointers-react/package.json b/packages/pointers-react/package.json
index 472790f6a..0bbfde890 100644
--- a/packages/pointers-react/package.json
+++ b/packages/pointers-react/package.json
@@ -35,7 +35,8 @@
   "scripts": {
     "build": "rm -rf dist && tsc --build tsconfig.build.json && copyfiles -u 1 \"src/**/*.css\" dist/src",
     "prepare": "yarn build",
-    "watch": "tsc --watch --preserveWatchOutput",
+    "typecheck": "tsc -p tsconfig.typecheck.json",
+    "watch": "copyfiles -u 1 \"src/**/*.css\" dist/src && concurrently --names=tsc,css \"tsc --watch --preserveWatchOutput\" \"nodemon --watch src -e css --exec 'copyfiles -u 1 \\\"src/**/*.css\\\" dist/src'\"",
     "test": "vitest run"
   },
   "dependencies": {
@@ -47,7 +48,9 @@
     "@testing-library/react": "^16.0.0",
     "@types/react": "^18.2.43",
     "@types/react-dom": "^18.2.17",
+    "concurrently": "^8.2.2",
     "jsdom": "^26.0.0",
+    "nodemon": "^3.1.11",
     "react": "^18.2.0",
     "react-dom": "^18.2.0",
     "typescript": "^5.0.0",
diff --git a/packages/pointers-react/tsconfig.typecheck.json b/packages/pointers-react/tsconfig.typecheck.json
new file mode 100644
index 000000000..6e118cf76
--- /dev/null
+++ b/packages/pointers-react/tsconfig.typecheck.json
@@ -0,0 +1,13 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "noEmit": true,
+    "composite": false,
+    "incremental": false,
+    "rootDir": "../..",
+    "paths": {
+      "@ethdebug/format": ["../format/src/index.ts"],
+      "@ethdebug/pointers": ["../pointers/src/index.ts"]
+    }
+  }
+}
diff --git a/packages/pointers/package.json b/packages/pointers/package.json
index cc56ec946..8cebbbf4d 100644
--- a/packages/pointers/package.json
+++ b/packages/pointers/package.json
@@ -51,6 +51,7 @@
   "scripts": {
     "build": "rm -rf dist && tsc --build tsconfig.build.json",
     "prepare": "yarn build",
+    "typecheck": "tsc -p tsconfig.typecheck.json",
     "run-example": "tsx bin/run-example.ts",
     "watch": "tsc --build --watch",
     "test": "vitest"
diff --git a/packages/pointers/tsconfig.json b/packages/pointers/tsconfig.json
index 5621f6e66..367a37264 100644
--- a/packages/pointers/tsconfig.json
+++ b/packages/pointers/tsconfig.json
@@ -15,5 +15,6 @@
       "#test/*": ["./test/*"]
     }
   },
+  "exclude": ["node_modules", "dist"],
   "references": [{ "path": "../format" }]
 }
diff --git a/packages/pointers/tsconfig.typecheck.json b/packages/pointers/tsconfig.typecheck.json
new file mode 100644
index 000000000..afe77567d
--- /dev/null
+++ b/packages/pointers/tsconfig.typecheck.json
@@ -0,0 +1,12 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "noEmit": true,
+    "composite": false,
+    "incremental": false,
+    "rootDir": "../..",
+    "paths": {
+      "@ethdebug/format": ["../format/src/index.ts"]
+    }
+  }
+}
diff --git a/packages/programs-react/package.json b/packages/programs-react/package.json
index e33c874fb..aa2e0b14d 100644
--- a/packages/programs-react/package.json
+++ b/packages/programs-react/package.json
@@ -20,22 +20,32 @@
   },
   "imports": {
     "#components/*": {
-      "types": "./src/components/*.tsx",
+      "types": [
+        "./src/components/*.tsx",
+        "./src/components/*.ts"
+      ],
       "default": "./dist/src/components/*.js"
     },
     "#shiki/*": {
-      "types": "./src/shiki/*.ts",
+      "types": [
+        "./src/shiki/*.ts",
+        "./src/shiki/*.tsx"
+      ],
       "default": "./dist/src/shiki/*.js"
     },
     "#utils/*": {
-      "types": "./src/utils/*.ts",
+      "types": [
+        "./src/utils/*.ts",
+        "./src/utils/*.tsx"
+      ],
       "default": "./dist/src/utils/*.js"
     }
   },
   "scripts": {
     "build": "rm -rf dist && tsc --build tsconfig.build.json && copyfiles -u 1 \"src/**/*.css\" dist/src",
     "prepare": "yarn build",
-    "watch": "tsc --watch --preserveWatchOutput",
+    "typecheck": "tsc -p tsconfig.typecheck.json",
+    "watch": "copyfiles -u 1 \"src/**/*.css\" dist/src && concurrently --names=tsc,css \"tsc --watch --preserveWatchOutput\" \"nodemon --watch src -e css --exec 'copyfiles -u 1 \\\"src/**/*.css\\\" dist/src'\"",
     "test": "vitest run"
   },
   "dependencies": {
@@ -50,7 +60,9 @@
     "@testing-library/react": "^16.0.0",
     "@types/react": "^18.2.43",
     "@types/react-dom": "^18.2.17",
+    "concurrently": "^8.2.2",
     "jsdom": "^26.0.0",
+    "nodemon": "^3.1.11",
     "react": "^18.2.0",
     "react-dom": "^18.2.0",
     "typescript": "^5.0.0",
diff --git a/packages/programs-react/tsconfig.typecheck.json b/packages/programs-react/tsconfig.typecheck.json
new file mode 100644
index 000000000..6e118cf76
--- /dev/null
+++ b/packages/programs-react/tsconfig.typecheck.json
@@ -0,0 +1,13 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "noEmit": true,
+    "composite": false,
+    "incremental": false,
+    "rootDir": "../..",
+    "paths": {
+      "@ethdebug/format": ["../format/src/index.ts"],
+      "@ethdebug/pointers": ["../pointers/src/index.ts"]
+    }
+  }
+}
diff --git a/tsconfig.base.json b/tsconfig.base.json
index f702e0958..27a9e8d03 100644
--- a/tsconfig.base.json
+++ b/tsconfig.base.json
@@ -1,3 +1,17 @@
+/*
+ * Shared compiler options for every package.
+ *
+ * Each package's tsconfig.typecheck.json maps its @ethdebug/*
+ * dependencies to sibling source, so `yarn typecheck` compiles a
+ * dependency's source under the DEPENDENT's compilerOptions. Keep
+ * per-package type-checking strictness uniform, or confine a stricter
+ * setting to a package nothing else depends on: a package that relaxes
+ * an option its dependents set would report errors in its own source
+ * only when a dependent checks it. Today only format adds
+ * exactOptionalPropertyTypes; turning that option on can only add
+ * errors, so a dependent, which leaves it off, simply checks format's
+ * source less strictly than format itself does.
+ */
 {
   "compilerOptions": {
     /* Visit https://aka.ms/tsconfig to read more about this file */