diff --git a/packages/cli/src/commands/commands.ts b/packages/cli/src/commands/commands.ts
index f27f4804f5..ba11cd7630 100644
--- a/packages/cli/src/commands/commands.ts
+++ b/packages/cli/src/commands/commands.ts
@@ -275,15 +275,36 @@ const Root = Spec.make(typeof OPENCODE_CLI_NAME === "string" ? OPENCODE_CLI_NAME
         Spec.make("stop", { description: "Stop the background server" }),
         Spec.make("get", {
           description: "Get service configuration",
-          params: { key: Argument.string("key").pipe(Argument.optional) },
+          params: {
+            key: Argument.string("key").pipe(Argument.withDescription("Service setting or env"), Argument.optional),
+            name: Argument.string("name").pipe(
+              Argument.withDescription("Environment variable name"),
+              Argument.optional,
+            ),
+          },
         }),
         Spec.make("set", {
           description: "Set service configuration",
-          params: { key: Argument.string("key"), value: Argument.string("value") },
+          params: {
+            key: Argument.string("key").pipe(Argument.withDescription("Service setting or env")),
+            value: Argument.string("value").pipe(
+              Argument.withDescription("Setting value or environment variable name"),
+            ),
+            nestedValue: Argument.string("env-value").pipe(
+              Argument.withDescription("Environment variable value"),
+              Argument.optional,
+            ),
+          },
         }),
         Spec.make("unset", {
           description: "Unset service configuration",
-          params: { key: Argument.string("key") },
+          params: {
+            key: Argument.string("key").pipe(Argument.withDescription("Service setting or env")),
+            name: Argument.string("name").pipe(
+              Argument.withDescription("Environment variable name"),
+              Argument.optional,
+            ),
+          },
         }),
       ],
     }),
diff --git a/packages/cli/src/commands/handlers/service/get.ts b/packages/cli/src/commands/handlers/service/get.ts
index fd4b9af384..8130e3e1db 100644
--- a/packages/cli/src/commands/handlers/service/get.ts
+++ b/packages/cli/src/commands/handlers/service/get.ts
@@ -7,6 +7,8 @@ import { ServiceConfig } from "../../../services/service-config"
 export default Runtime.handler(
   Commands.commands.service.commands.get,
   Effect.fn("cli.service.get")(function* (input) {
-    process.stdout.write((yield* ServiceConfig.get(Option.getOrUndefined(input.key))) + EOL)
+    process.stdout.write(
+      (yield* ServiceConfig.get(Option.getOrUndefined(input.key), Option.getOrUndefined(input.name))) + EOL,
+    )
   }),
 )
diff --git a/packages/cli/src/commands/handlers/service/set.ts b/packages/cli/src/commands/handlers/service/set.ts
index f761c02411..5e8e421efc 100644
--- a/packages/cli/src/commands/handlers/service/set.ts
+++ b/packages/cli/src/commands/handlers/service/set.ts
@@ -1,4 +1,4 @@
-import { Effect } from "effect"
+import { Effect, Option } from "effect"
 import { Commands } from "../../commands"
 import { Runtime } from "../../../framework/runtime"
 import { ServiceConfig } from "../../../services/service-config"
@@ -6,6 +6,6 @@ import { ServiceConfig } from "../../../services/service-config"
 export default Runtime.handler(
   Commands.commands.service.commands.set,
   Effect.fn("cli.service.set")(function* (input) {
-    yield* ServiceConfig.set(input.key, input.value)
+    yield* ServiceConfig.set(input.key, input.value, Option.getOrUndefined(input.nestedValue))
   }),
 )
diff --git a/packages/cli/src/commands/handlers/service/unset.ts b/packages/cli/src/commands/handlers/service/unset.ts
index cc738125d3..cbcda88252 100644
--- a/packages/cli/src/commands/handlers/service/unset.ts
+++ b/packages/cli/src/commands/handlers/service/unset.ts
@@ -1,4 +1,4 @@
-import { Effect } from "effect"
+import { Effect, Option } from "effect"
 import { Commands } from "../../commands"
 import { Runtime } from "../../../framework/runtime"
 import { ServiceConfig } from "../../../services/service-config"
@@ -6,6 +6,6 @@ import { ServiceConfig } from "../../../services/service-config"
 export default Runtime.handler(
   Commands.commands.service.commands.unset,
   Effect.fn("cli.service.unset")(function* (input) {
-    yield* ServiceConfig.unset(input.key)
+    yield* ServiceConfig.unset(input.key, Option.getOrUndefined(input.name))
   }),
 )
diff --git a/packages/cli/src/services/service-config.ts b/packages/cli/src/services/service-config.ts
index 53d9a0ccc1..9eeebfb164 100644
--- a/packages/cli/src/services/service-config.ts
+++ b/packages/cli/src/services/service-config.ts
@@ -15,10 +15,11 @@ export const Info = Schema.Struct({
   hostname: Schema.optional(Schema.String),
   port: Schema.optional(Schema.Int.check(Schema.isGreaterThanOrEqualTo(1), Schema.isLessThanOrEqualTo(65_535))),
   password: Schema.optional(Schema.String),
+  env: Schema.optional(Schema.Record(Schema.String, Schema.String)),
 })
 export type Info = typeof Info.Type
 
-const keys = ["hostname", "port", "password"] as const
+const keys = ["hostname", "port", "password", "env"] as const
 type Key = (typeof keys)[number]
 
 const decodeInfo = Schema.decodeUnknownEffect(Schema.fromJsonString(Info))
@@ -76,7 +77,7 @@ export const migrateConfig = Effect.fnUntraced(function* (legacy: string, file:
 })
 
 function configKey(key: string): Key {
-  if (key === "hostname" || key === "port" || key === "password") return key
+  if (key === "hostname" || key === "port" || key === "password" || key === "env") return key
   throw new Error(`Unknown service config key: ${key}`)
 }
 
@@ -104,6 +105,7 @@ export const options = Effect.fnUntraced(function* (input: { readonly checkVersi
   return {
     file,
     version: input.checkVersion ? OPENCODE_VERSION : undefined,
+    env: (yield* read()).env,
     command: [
       ...selfCommand(),
       "serve",
@@ -141,12 +143,14 @@ export const password = Effect.fn("cli.service-config.password")(function* (valu
   return next
 })
 
-export const get = Effect.fn("cli.service-config.get")(function* (key?: string) {
+export const get = Effect.fn("cli.service-config.get")(function* (key?: string, name?: string) {
   if (key === undefined) {
     const { password: _password, ...safe } = yield* read()
     return JSON.stringify(safe, null, 2)
   }
-  switch (configKey(key)) {
+  const selected = configKey(key)
+  if (selected !== "env" && name !== undefined) throw new Error(`Usage: opencode service get ${selected}`)
+  switch (selected) {
     case "hostname": {
       return (yield* read()).hostname ?? ""
     }
@@ -157,12 +161,19 @@ export const get = Effect.fn("cli.service-config.get")(function* (key?: string)
     case "password": {
       return yield* password()
     }
+    case "env": {
+      const env = (yield* read()).env ?? {}
+      return name === undefined ? JSON.stringify(env, null, 2) : (env[name] ?? "")
+    }
   }
   throw new Error(`Unknown service config key: ${key}`)
 })
 
-export const set = Effect.fn("cli.service-config.set")(function* (key: string, value: string) {
-  switch (configKey(key)) {
+export const set = Effect.fn("cli.service-config.set")(function* (key: string, value: string, nestedValue?: string) {
+  const selected = configKey(key)
+  if (selected !== "env" && nestedValue !== undefined)
+    throw new Error(`Usage: opencode service set ${selected} <value>`)
+  switch (selected) {
     case "hostname": {
       yield* Service.stop(yield* options())
       yield* write({ ...(yield* read()), hostname: value })
@@ -180,11 +191,20 @@ export const set = Effect.fn("cli.service-config.set")(function* (key: string, v
       yield* password(value)
       return
     }
+    case "env": {
+      if (nestedValue === undefined) throw new Error("Usage: opencode service set env <key> <value>")
+      yield* Service.stop(yield* options())
+      const existing = yield* read()
+      yield* write({ ...existing, env: { ...existing.env, [value]: nestedValue } })
+      return
+    }
   }
 })
 
-export const unset = Effect.fn("cli.service-config.unset")(function* (key: string) {
-  switch (configKey(key)) {
+export const unset = Effect.fn("cli.service-config.unset")(function* (key: string, name?: string) {
+  const selected = configKey(key)
+  if (selected !== "env" && name !== undefined) throw new Error(`Usage: opencode service unset ${selected}`)
+  switch (selected) {
     case "hostname": {
       yield* Service.stop(yield* options())
       const { hostname: _hostname, ...next } = yield* read()
@@ -203,6 +223,15 @@ export const unset = Effect.fn("cli.service-config.unset")(function* (key: strin
       yield* write(next)
       return
     }
+    case "env": {
+      if (name === undefined) throw new Error("Usage: opencode service unset env <key>")
+      yield* Service.stop(yield* options())
+      const existing = yield* read()
+      const { [name]: _removed, ...env } = existing.env ?? {}
+      const { env: _existingEnv, ...rest } = existing
+      yield* write(Object.keys(env).length === 0 ? rest : { ...rest, env })
+      return
+    }
   }
 })
 
diff --git a/packages/cli/test/service.test.ts b/packages/cli/test/service.test.ts
index 704d8773b1..a669e1f5b3 100644
--- a/packages/cli/test/service.test.ts
+++ b/packages/cli/test/service.test.ts
@@ -60,6 +60,44 @@ test("local channel stores service config with the local service filename", asyn
   }
 })
 
+test("service config manages environment variables", async () => {
+  const root = await fs.mkdtemp(path.join(os.tmpdir(), "opencode-service-env-"))
+  const layer = Global.layerWith({ config: path.join(root, "config"), state: path.join(root, "state") })
+  try {
+    await Effect.runPromise(
+      ServiceConfig.set("env", "OPENCODE_SERVICE_ENV_TEST", "configured").pipe(
+        Effect.provide(layer),
+        Effect.provide(NodeFileSystem.layer),
+      ),
+    )
+    expect(
+      await Effect.runPromise(
+        ServiceConfig.get("env", "OPENCODE_SERVICE_ENV_TEST").pipe(
+          Effect.provide(layer),
+          Effect.provide(NodeFileSystem.layer),
+        ),
+      ),
+    ).toBe("configured")
+    expect(
+      (
+        await Effect.runPromise(
+          ServiceConfig.options().pipe(Effect.provide(layer), Effect.provide(NodeFileSystem.layer)),
+        )
+      ).env,
+    ).toEqual({ OPENCODE_SERVICE_ENV_TEST: "configured" })
+
+    await Effect.runPromise(
+      ServiceConfig.unset("env", "OPENCODE_SERVICE_ENV_TEST").pipe(
+        Effect.provide(layer),
+        Effect.provide(NodeFileSystem.layer),
+      ),
+    )
+    expect(await Bun.file(path.join(root, "config", "service-local.json")).json()).toEqual({})
+  } finally {
+    await fs.rm(root, { recursive: true, force: true })
+  }
+})
+
 test("service filenames share release channels and identify preview channels", () => {
   expect(ServiceConfig.filename("latest")).toBe("service.json")
   expect(ServiceConfig.filename("dev")).toBe("service.json")
diff --git a/packages/client/src/effect/service.ts b/packages/client/src/effect/service.ts
index f7e8450f8b..53ee19fd87 100644
--- a/packages/client/src/effect/service.ts
+++ b/packages/client/src/effect/service.ts
@@ -71,7 +71,7 @@ export const ensure = Effect.fn("service.ensure")(function* (options: EnsureOpti
     if (command === undefined) return yield* Effect.fail(new Error("Missing service command"))
     return yield* Effect.try({
       try: () => {
-        return spawnServiceContender(command, args)
+        return spawnServiceContender(command, args, options.env)
       },
       catch: (cause) => new Error("Failed to start server", { cause }),
     })
diff --git a/packages/client/src/promise/service.ts b/packages/client/src/promise/service.ts
index bc16f0ad4c..a0f2ad5176 100644
--- a/packages/client/src/promise/service.ts
+++ b/packages/client/src/promise/service.ts
@@ -51,7 +51,7 @@ export async function ensure(options: EnsureOptions = {}): Promise<Endpoint> {
     const [command, ...args] = options.command ?? ["opencode", "serve", "--service"]
     if (command === undefined) throw new Error("Missing service command")
     try {
-      return spawnServiceContender(command, args)
+      return spawnServiceContender(command, args, options.env)
     } catch (cause) {
       throw new Error("Failed to start server", { cause })
     }
diff --git a/packages/client/src/service-contender.ts b/packages/client/src/service-contender.ts
index f4c4de085b..5d60bf4d60 100644
--- a/packages/client/src/service-contender.ts
+++ b/packages/client/src/service-contender.ts
@@ -10,8 +10,16 @@ export type ServiceContender = {
 
 const stderrLimit = 8 * 1024
 
-export function spawnServiceContender(command: string, args: ReadonlyArray<string>): ServiceContender {
-  const child = spawn(command, args, { detached: true, stdio: ["ignore", "ignore", "pipe"] })
+export function spawnServiceContender(
+  command: string,
+  args: ReadonlyArray<string>,
+  env?: Readonly<Record<string, string>>,
+): ServiceContender {
+  const child = spawn(command, args, {
+    detached: true,
+    stdio: ["ignore", "ignore", "pipe"],
+    env: { ...process.env, ...env },
+  })
   let error: Error | undefined
   let closed = false
   let stderr = Buffer.alloc(0)
diff --git a/packages/client/src/service.ts b/packages/client/src/service.ts
index 65c3226643..1db78885aa 100644
--- a/packages/client/src/service.ts
+++ b/packages/client/src/service.ts
@@ -28,6 +28,8 @@ export type EnsureReason = "missing" | "version-mismatch"
 export type EnsureOptions = DiscoverOptions & {
   /** Service command and arguments. Defaults to `opencode serve --service`. */
   readonly command?: ReadonlyArray<string>
+  /** Environment variables added to the inherited service process environment. */
+  readonly env?: Readonly<Record<string, string>>
   /** Called once before spawning a new service process. */
   readonly onStart?: (reason: EnsureReason, previousVersion?: string) => void
 }
diff --git a/packages/client/test/fixture/service.ts b/packages/client/test/fixture/service.ts
index e4205d711f..3128f9f8a6 100644
--- a/packages/client/test/fixture/service.ts
+++ b/packages/client/test/fixture/service.ts
@@ -11,6 +11,8 @@ if (mode === "record-start") {
   await writeFile(registration + ".started", "")
   process.exit(1)
 }
+if (mode === "environment")
+  await writeFile(registration + ".environment", process.env.OPENCODE_SERVICE_ENV_TEST ?? "")
 if (mode === "signal") process.kill(process.pid, process.platform === "win32" ? "SIGTERM" : "SIGKILL")
 
 if (mode === "delayed" || mode === "delayed-failed" || mode === "coordinated" || mode === "coordinated-failed-loser") {
diff --git a/packages/client/test/promise-service.test.ts b/packages/client/test/promise-service.test.ts
index 6d6a766014..2f344015c8 100644
--- a/packages/client/test/promise-service.test.ts
+++ b/packages/client/test/promise-service.test.ts
@@ -59,6 +59,26 @@ test("ensures a missing service with native promises", async () => {
   }
 })
 
+test("adds configured environment variables with native promises", async () => {
+  const directory = await temp()
+  const registration = join(directory, "service.json")
+  const endpoint = await ensure({
+    file: registration,
+    version: "test",
+    command: [process.execPath, fixture, registration, "environment"],
+    env: { OPENCODE_SERVICE_ENV_TEST: "configured" },
+  })
+  const info = await Bun.file(registration).json()
+
+  try {
+    expect(endpoint.url).toBe(info.url)
+    expect(await Bun.file(registration + ".environment").text()).toBe("configured")
+  } finally {
+    process.kill(info.pid, "SIGTERM")
+    await waitForExit(info.pid)
+  }
+})
+
 test("waits for a live contender when another native contender fails", async () => {
   const directory = await temp()
   const registration = join(directory, "service.json")
diff --git a/packages/client/test/service.test.ts b/packages/client/test/service.test.ts
index dc99cec6ae..7f3da0e32c 100644
--- a/packages/client/test/service.test.ts
+++ b/packages/client/test/service.test.ts
@@ -68,6 +68,28 @@ test("reuses a compatible registered service", async () => {
   expect(existing.exitCode).toBe(null)
 })
 
+test("adds configured environment variables when starting a service", async () => {
+  const directory = await temp()
+  const registration = join(directory, "service.json")
+  const endpoint = await run(
+    ensure({
+      file: registration,
+      version: "test",
+      command: [process.execPath, fixture, registration, "environment"],
+      env: { OPENCODE_SERVICE_ENV_TEST: "configured" },
+    }),
+  )
+  const info = await Bun.file(registration).json()
+
+  try {
+    expect(endpoint.url).toBe(info.url)
+    expect(await Bun.file(registration + ".environment").text()).toBe("configured")
+  } finally {
+    process.kill(info.pid, "SIGTERM")
+    await waitForExit(info.pid)
+  }
+})
+
 test("replaces an incompatible registered service", async () => {
   const directory = await temp()
   const registration = join(directory, "service.json")