feat: add experimental.enable_exa config setting

packages/core/src/v1/config/config.ts

@@ -179,6 +179,9 @@ export const Info = Schema.Struct({
       policies: Schema.optional(Schema.mutable(Schema.Array(ConfigExperimental.Policy))).annotate({
         description: "Policy statements applied to supported resources, such as provider access",
       }),
+      enable_exa: Schema.optional(Schema.Boolean).annotate({
+        description: "Enable experimental Exa features",
+      }),
     }),
   ),
 }).annotate({ identifier: "Config" })

packages/opencode/src/config/config.ts

@@ -20,6 +20,7 @@ import { InstanceState } from "@/effect/instance-state"
 import { Context, Duration, Effect, Exit, Fiber, Layer, Option, Schema } from "effect"
 import { FetchHttpClient, HttpClient, HttpClientRequest, HttpClientResponse } from "effect/unstable/http"
 import { EffectFlock } from "@opencode-ai/core/util/effect-flock"
+import { makeRuntime } from "@/effect/run-service"
 import { containsPath, type InstanceContext } from "../project/instance-context"
 import { ConfigV1 } from "@opencode-ai/core/v1/config/config"
 import { ConfigPermissionV1 } from "@opencode-ai/core/v1/config/permission"
@@ -676,4 +677,19 @@ export const defaultLayer = layer.pipe(
   Layer.provide(FetchHttpClient.layer),
 )
 
+const { runPromise } = makeRuntime(Service, defaultLayer)
+
+export async function experimentalEnableExa(): Promise<boolean> {
+  if (envTruthy("OPENCODE_EXPERIMENTAL") || envTruthy("OPENCODE_ENABLE_EXA") || envTruthy("OPENCODE_EXPERIMENTAL_EXA")) {
+    return true
+  }
+  const config = await runPromise((svc) => svc.get())
+  return config.experimental?.enable_exa === true
+}
+
+function envTruthy(key: string) {
+  const value = process.env[key]?.toLowerCase()
+  return value === "true" || value === "1"
+}
+
 export * as Config from "./config"

packages/opencode/src/tool/registry.ts

@@ -311,9 +311,13 @@ export const layer: Layer.Layer<
     })
 
     const tools: Interface["tools"] = Effect.fn("ToolRegistry.tools")(function* (input) {
+      const cfg = yield* config.get()
       const filtered = (yield* all()).filter((tool) => {
         if (tool.id === WebSearchTool.id) {
-          return webSearchEnabled(input.providerID, { exa: flags.enableExa, parallel: flags.enableParallel })
+          return webSearchEnabled(input.providerID, {
+            exa: flags.enableExa || cfg.experimental?.enable_exa === true,
+            parallel: flags.enableParallel,
+          })
         }
 
         const usePatch =