diff --git a/packages/coding-agent/test/session-file-invalid.test.ts b/packages/coding-agent/test/session-file-invalid.test.ts
index c69ef43a1..e2eb7015c 100644
--- a/packages/coding-agent/test/session-file-invalid.test.ts
+++ b/packages/coding-agent/test/session-file-invalid.test.ts
@@ -6,6 +6,7 @@ import { afterEach, describe, expect, it } from "vitest";
 import { ENV_AGENT_DIR } from "../src/config.ts";
 
 const cliPath = resolve(__dirname, "../src/cli.ts");
+const sourceResolverPath = resolve(__dirname, "../src/experimental/source-resolver.ts");
 const tempDirs: string[] = [];
 
 afterEach(() => {
@@ -23,13 +24,12 @@ function createTempDir(): string {
 async function runCli(args: string[], cwd: string, agentDir: string): Promise<{ code: number | null; stderr: string }> {
 	let stderr = "";
 	const code = await new Promise<number | null>((resolvePromise, reject) => {
-		const child = spawn(process.execPath, [cliPath, ...args], {
+		const child = spawn(process.execPath, ["--import", sourceResolverPath, cliPath, ...args], {
 			cwd,
 			env: {
 				...process.env,
 				[ENV_AGENT_DIR]: agentDir,
 				PI_OFFLINE: "1",
-				TSX_TSCONFIG_PATH: resolve(__dirname, "../../../tsconfig.json"),
 			},
 			stdio: ["ignore", "ignore", "pipe"],
 		});
diff --git a/packages/coding-agent/test/session-id-readonly.test.ts b/packages/coding-agent/test/session-id-readonly.test.ts
index 5527193ec..20a129977 100644
--- a/packages/coding-agent/test/session-id-readonly.test.ts
+++ b/packages/coding-agent/test/session-id-readonly.test.ts
@@ -10,6 +10,7 @@ import { SettingsManager } from "../src/core/settings-manager.ts";
 import { createSessionManager } from "../src/main.ts";
 
 const cliPath = resolve(__dirname, "../src/cli.ts");
+const sourceResolverPath = resolve(__dirname, "../src/experimental/source-resolver.ts");
 const tempDirs: string[] = [];
 
 afterEach(() => {
@@ -54,13 +55,12 @@ async function runCli(args: string[]): Promise<{ code: number | null; agentDir:
 	mkdirSync(projectDir, { recursive: true });
 
 	const code = await new Promise<number | null>((resolvePromise, reject) => {
-		const child = spawn(process.execPath, [cliPath, ...args], {
+		const child = spawn(process.execPath, ["--import", sourceResolverPath, cliPath, ...args], {
 			cwd: projectDir,
 			env: {
 				...process.env,
 				[ENV_AGENT_DIR]: agentDir,
 				PI_OFFLINE: "1",
-				TSX_TSCONFIG_PATH: resolve(__dirname, "../../../tsconfig.json"),
 			},
 			stdio: ["ignore", "ignore", "ignore"],
 		});
diff --git a/packages/coding-agent/test/startup-session-name.test.ts b/packages/coding-agent/test/startup-session-name.test.ts
index 3571ce666..c953cd1ae 100644
--- a/packages/coding-agent/test/startup-session-name.test.ts
+++ b/packages/coding-agent/test/startup-session-name.test.ts
@@ -6,6 +6,7 @@ import { afterEach, describe, expect, it } from "vitest";
 import { ENV_AGENT_DIR } from "../src/config.ts";
 
 const cliPath = resolve(__dirname, "../src/cli.ts");
+const sourceResolverPath = resolve(__dirname, "../src/experimental/source-resolver.ts");
 const tempDirs: string[] = [];
 
 afterEach(() => {
@@ -65,13 +66,12 @@ function readSessionInfoNames(sessionFile: string): string[] {
 
 async function runCli(args: string[], dirs: CliDirs): Promise<CliResult> {
 	let stderr = "";
-	const child = spawn(process.execPath, [cliPath, ...args], {
+	const child = spawn(process.execPath, ["--import", sourceResolverPath, cliPath, ...args], {
 		cwd: dirs.projectDir,
 		env: {
 			...process.env,
 			[ENV_AGENT_DIR]: dirs.agentDir,
 			PI_OFFLINE: "1",
-			TSX_TSCONFIG_PATH: resolve(__dirname, "../../../tsconfig.json"),
 		},
 		stdio: ["ignore", "ignore", "pipe"],
 	});
diff --git a/packages/coding-agent/test/stdout-cleanliness.test.ts b/packages/coding-agent/test/stdout-cleanliness.test.ts
index a5ffa5e68..baaf296a5 100644
--- a/packages/coding-agent/test/stdout-cleanliness.test.ts
+++ b/packages/coding-agent/test/stdout-cleanliness.test.ts
@@ -7,6 +7,7 @@ import { ENV_AGENT_DIR } from "../src/config.ts";
 import { allowNetwork } from "./test-network-env.ts";
 
 const cliPath = resolve(__dirname, "../src/cli.ts");
+const sourceResolverPath = resolve(__dirname, "../src/experimental/source-resolver.ts");
 
 const tempDirs: string[] = [];
 
@@ -59,12 +60,11 @@ async function runCli(args: string[]): Promise<{ stdout: string; stderr: string;
 	);
 
 	return await new Promise((resolvePromise, reject) => {
-		const child = spawn(process.execPath, [cliPath, ...args], {
+		const child = spawn(process.execPath, ["--import", sourceResolverPath, cliPath, ...args], {
 			cwd: projectDir,
 			env: {
 				...process.env,
 				[ENV_AGENT_DIR]: agentDir,
-				TSX_TSCONFIG_PATH: resolve(__dirname, "../../../tsconfig.json"),
 			},
 			stdio: ["ignore", "pipe", "pipe"],
 		});
diff --git a/vitest.base.ts b/vitest.base.ts
index d21ad3b7e..9394bcb1e 100644
--- a/vitest.base.ts
+++ b/vitest.base.ts
@@ -2,6 +2,11 @@ import { fileURLToPath } from "node:url";
 import { defineConfig } from "vitest/config";
 
 export const workspaceSourcePaths = {
+	chordIndex: fileURLToPath(new URL("./packages/chord/src/index.ts", import.meta.url)),
+	chordContext: fileURLToPath(new URL("./packages/chord/src/context/index.ts", import.meta.url)),
+	chordDelta: fileURLToPath(new URL("./packages/chord/src/delta/index.ts", import.meta.url)),
+	chordBundler: fileURLToPath(new URL("./packages/chord/src/bundler.ts", import.meta.url)),
+	chordNode: fileURLToPath(new URL("./packages/chord/src/node.ts", import.meta.url)),
 	telemetryIndex: fileURLToPath(new URL("./packages/telemetry/src/index.ts", import.meta.url)),
 	telemetryTesting: fileURLToPath(new URL("./packages/telemetry/src/testing/index.ts", import.meta.url)),
 	aiIndex: fileURLToPath(new URL("./packages/ai/src/index.ts", import.meta.url)),
@@ -21,8 +26,12 @@ export const workspaceSourcePaths = {
 
 export default defineConfig({
 	resolve: {
-		conditions: ["source"],
 		alias: [
+			{ find: /^@earendil-works\/chord$/, replacement: workspaceSourcePaths.chordIndex },
+			{ find: /^@earendil-works\/chord\/context$/, replacement: workspaceSourcePaths.chordContext },
+			{ find: /^@earendil-works\/chord\/delta$/, replacement: workspaceSourcePaths.chordDelta },
+			{ find: /^@earendil-works\/chord\/bundler$/, replacement: workspaceSourcePaths.chordBundler },
+			{ find: /^@earendil-works\/chord\/node$/, replacement: workspaceSourcePaths.chordNode },
 			{ find: /^@earendil-works\/pi-telemetry$/, replacement: workspaceSourcePaths.telemetryIndex },
 			{ find: /^@earendil-works\/pi-telemetry\/testing$/, replacement: workspaceSourcePaths.telemetryTesting },
 			{ find: /^@earendil-works\/pi-ai$/, replacement: workspaceSourcePaths.aiIndex },
@@ -42,5 +51,4 @@ export default defineConfig({
 			{ find: /^@earendil-works\/pi-tui$/, replacement: workspaceSourcePaths.tuiIndex },
 		],
 	},
-	ssr: { resolve: { conditions: ["source"] } },
 });