feat: support workspace variable interpolation in Provider Custom Headers

- Add interpolateHeaders function to src/utils/config.ts
- Supports ${workspaceFolder}, ${workspaceFolderBasename}, and ${env:VAR_NAME}
- Integrate into buildApiHandler for all API providers
- Update getOpenAiModels to interpolate headers when fetching models
- Add comprehensive tests for the new functionality

Closes #11165

.changeset/warm-taxes-build.md

@@ -0,0 +1,5 @@
+---
+"roo-code": minor
+---
+
+Added support for VS Code variable interpolation in Provider Custom Headers. Users can now use `${workspaceFolderBasename}`, `${workspaceFolder}`, and `${env:VAR_NAME}` patterns in custom header values, enabling per-project tracking and routing without creating multiple provider profiles.

src/api/index.ts

@@ -3,6 +3,8 @@ import OpenAI from "openai"
 
 import type { ProviderSettings, ModelInfo } from "@roo-code/types"
 
+import { interpolateHeaders } from "../utils/config"
+
 import { ApiStream } from "./transform/stream"
 
 import {
@@ -122,6 +124,11 @@ export interface ApiHandler {
 export function buildApiHandler(configuration: ProviderSettings): ApiHandler {
 	const { apiProvider, ...options } = configuration
 
+	// Interpolate variables in custom headers (e.g., ${workspaceFolderBasename}, ${env:VAR_NAME})
+	if (options.openAiHeaders) {
+		options.openAiHeaders = interpolateHeaders(options.openAiHeaders)
+	}
+
 	switch (apiProvider) {
 		case "anthropic":
 			return new AnthropicHandler(options)

src/api/providers/openai.ts

@@ -13,6 +13,7 @@ import {
 import type { ApiHandlerOptions } from "../../shared/api"
 
 import { TagMatcher } from "../../utils/tag-matcher"
+import { interpolateHeaders } from "../../utils/config"
 
 import { convertToOpenAiMessages } from "../transform/openai-format"
 import { convertToR1Format } from "../transform/r1-format"
@@ -542,9 +543,11 @@ export async function getOpenAiModels(baseUrl?: string, apiKey?: string, openAiH
 		}
 
 		const config: Record<string, any> = {}
+		// Interpolate variables in custom headers (e.g., ${workspaceFolderBasename}, ${env:VAR_NAME})
+		const interpolatedHeaders = interpolateHeaders(openAiHeaders)
 		const headers: Record<string, string> = {
 			...DEFAULT_HEADERS,
-			...(openAiHeaders || {}),
+			...(interpolatedHeaders || {}),
 		}
 
 		if (apiKey) {

src/utils/__tests__/config.spec.ts

@@ -1,6 +1,19 @@
 // npx vitest utils/__tests__/config.spec.ts
 
-import { injectEnv, injectVariables } from "../config"
+import { injectEnv, injectVariables, interpolateHeaders } from "../config"
+
+// Mock vscode module for interpolateHeaders tests
+vi.mock("vscode", () => ({
+	workspace: {
+		workspaceFolders: [
+			{
+				uri: {
+					fsPath: "/home/user/projects/my-awesome-app",
+				},
+			},
+		],
+	},
+}))
 
 describe("injectEnv", () => {
 	const originalEnv = process.env
@@ -253,3 +266,107 @@ describe("injectVariables", () => {
 
 	// Variable maps are already tested by `injectEnv` tests above.
 })
+
+describe("interpolateHeaders", () => {
+	const originalEnv = process.env
+
+	beforeEach(() => {
+		vitest.resetModules()
+		process.env = { ...originalEnv }
+	})
+
+	afterAll(() => {
+		process.env = originalEnv
+	})
+
+	it("should return undefined for undefined headers", () => {
+		const result = interpolateHeaders(undefined)
+		expect(result).toBeUndefined()
+	})
+
+	it("should return empty object for empty headers", () => {
+		const result = interpolateHeaders({})
+		expect(result).toEqual({})
+	})
+
+	it("should pass through headers without variables unchanged", () => {
+		const headers = {
+			"Content-Type": "application/json",
+			"X-Custom-Header": "static-value",
+		}
+		const result = interpolateHeaders(headers)
+		expect(result).toEqual(headers)
+	})
+
+	it("should interpolate ${workspaceFolderBasename} variable", () => {
+		const headers = {
+			"X-App-ID": "${workspaceFolderBasename}",
+			"X-Other": "static",
+		}
+		const result = interpolateHeaders(headers)
+		expect(result).toEqual({
+			"X-App-ID": "my-awesome-app",
+			"X-Other": "static",
+		})
+	})
+
+	it("should interpolate ${workspaceFolder} variable", () => {
+		const headers = {
+			"X-Workspace": "${workspaceFolder}",
+		}
+		const result = interpolateHeaders(headers)
+		expect(result).toEqual({
+			"X-Workspace": "/home/user/projects/my-awesome-app",
+		})
+	})
+
+	it("should interpolate ${env:VAR_NAME} variables", () => {
+		process.env.MY_API_KEY = "secret-key-123"
+		const headers = {
+			Authorization: "Bearer ${env:MY_API_KEY}",
+		}
+		const result = interpolateHeaders(headers)
+		expect(result).toEqual({
+			Authorization: "Bearer secret-key-123",
+		})
+	})
+
+	it("should handle mixed variables in headers", () => {
+		process.env.TENANT_ID = "tenant-001"
+		const headers = {
+			"X-App-ID": "${workspaceFolderBasename}",
+			"X-Tenant-ID": "${env:TENANT_ID}",
+			"X-Static": "no-variables",
+		}
+		const result = interpolateHeaders(headers)
+		expect(result).toEqual({
+			"X-App-ID": "my-awesome-app",
+			"X-Tenant-ID": "tenant-001",
+			"X-Static": "no-variables",
+		})
+	})
+
+	it("should handle missing env variables by keeping the original pattern", () => {
+		const consoleWarnSpy = vitest.spyOn(console, "warn").mockImplementation(() => {})
+		const headers = {
+			"X-Missing": "${env:NON_EXISTENT_VAR}",
+		}
+		const result = interpolateHeaders(headers)
+		expect(result).toEqual({
+			"X-Missing": "${env:NON_EXISTENT_VAR}",
+		})
+		expect(consoleWarnSpy).toHaveBeenCalled()
+		consoleWarnSpy.mockRestore()
+	})
+
+	it("should interpolate multiple variables in a single header value", () => {
+		process.env.PREFIX = "prod"
+		const headers = {
+			"X-Identifier": "${env:PREFIX}-${workspaceFolderBasename}",
+		}
+		const result = interpolateHeaders(headers)
+		expect(result).toEqual({
+			"X-Identifier": "prod-my-awesome-app",
+		})
+	})
+})

src/utils/config.ts

@@ -1,3 +1,6 @@
+import * as vscode from "vscode"
+import * as path from "path"
+
 export type InjectableConfigType =
 	| string
 	| {
@@ -64,3 +67,77 @@ export async function injectVariables<C extends InjectableConfigType>(
 
 	return (isObject ? JSON.parse(configString) : configString) as C extends string ? string : C
 }
+
+/**
+ * Synchronously injects variables into a string value.
+ * Used for interpolating individual header values.
+ *
+ * @param value The string value to interpolate
+ * @param variables The variables to inject
+ * @returns The interpolated string
+ */
+function injectVariablesSync(
+	value: string,
+	variables: Record<string, undefined | null | string | Record<string, undefined | null | string>>,
+): string {
+	let result = value
+
+	for (const [key, varValue] of Object.entries(variables)) {
+		if (varValue == null) continue
+
+		if (typeof varValue === "string") {
+			// Normalize paths to forward slashes for cross-platform compatibility
+			result = result.replace(new RegExp(`\\$\\{${key}\\}`, "g"), varValue.toPosix())
+		} else {
+			// Handle nested variables (e.g., ${env:VAR_NAME})
+			result = result.replace(new RegExp(`\\$\\{${key}:([\\w]+)\\}`, "g"), (match, name) => {
+				const nestedValue = varValue[name]
+
+				if (nestedValue == null) {
+					console.warn(`[injectVariablesSync] variable "${name}" referenced but not found in "${key}"`)
+					return match
+				}
+
+				// Normalize paths for string values
+				return typeof nestedValue === "string" ? nestedValue.toPosix() : nestedValue
+			})
+		}
+	}
+
+	return result
+}
+
+/**
+ * Synchronously interpolates VS Code-style variables in custom headers.
+ *
+ * Supports the following variables:
+ * - ${workspaceFolder} - Full path to the workspace root
+ * - ${workspaceFolderBasename} - Just the folder name (e.g., "my-repo-name")
+ * - ${env:VAR_NAME} - Environment variables
+ *
+ * This function is synchronous to be compatible with provider constructors.
+ *
+ * @param headers The headers object to interpolate (can be undefined)
+ * @returns The interpolated headers object, or undefined if input was undefined
+ */
+export function interpolateHeaders(headers: Record<string, string> | undefined): Record<string, string> | undefined {
+	if (!headers || Object.keys(headers).length === 0) {
+		return headers
+	}
+
+	const workspaceFolder = vscode.workspace.workspaceFolders?.[0]?.uri.fsPath ?? ""
+	const workspaceFolderBasename = workspaceFolder ? path.basename(workspaceFolder) : ""
+
+	const variables = {
+		workspaceFolder,
+		workspaceFolderBasename,
+		env: process.env as Record<string, string>,
+	}
+
+	const result: Record<string, string> = {}
+	for (const [headerKey, headerValue] of Object.entries(headers)) {
+		result[headerKey] = injectVariablesSync(headerValue, variables)
+	}
+
+	return result
+}