core: consolidate shared infrastructure into core package

Moves effect logging, observability, runtime utilities, flags, installation
version info, and process utilities from opencode to core package. This
enables better code sharing across packages and establishes core as the
single source of truth for foundational utilities.

All internal imports updated to use @opencode-ai/core paths for consistency.

4 files changed, 204 insertions, 0 deletions

diff --git a/packages/core/src/effect/logger.ts b/packages/core/src/effect/logger.ts
new file mode 100644
index 000000000..69f9631e0
--- /dev/null
+++ b/packages/core/src/effect/logger.ts
@@ -0,0 +1,73 @@
+import { Cause, Effect, Logger, References } from "effect"
+import * as Log from "../util/log"
+
+type Fields = Record<string, unknown>
+
+const normalizeKey = (key: string) => (key === "sessionID" ? "session.id" : key)
+
+export interface Handle {
+  readonly debug: (msg?: unknown, extra?: Fields) => Effect.Effect<void>
+  readonly info: (msg?: unknown, extra?: Fields) => Effect.Effect<void>
+  readonly warn: (msg?: unknown, extra?: Fields) => Effect.Effect<void>
+  readonly error: (msg?: unknown, extra?: Fields) => Effect.Effect<void>
+  readonly with: (extra: Fields) => Handle
+}
+
+const clean = (input?: Fields): Fields =>
+  Object.fromEntries(
+    Object.entries(input ?? {})
+      .filter((entry) => entry[1] !== undefined && entry[1] !== null)
+      .map(([key, value]) => [normalizeKey(key), value]),
+  )
+
+const text = (input: unknown): string => {
+  // oxlint-disable-next-line no-base-to-string
+  if (Array.isArray(input)) return input.map((item) => String(item)).join(" ")
+  // oxlint-disable-next-line no-base-to-string
+  return input === undefined ? "" : String(input)
+}
+
+const call = (run: (msg?: unknown) => Effect.Effect<void>, base: Fields, msg?: unknown, extra?: Fields) => {
+  const ann = clean({ ...base, ...extra })
+  const fx = run(msg)
+  return Object.keys(ann).length ? Effect.annotateLogs(fx, ann) : fx
+}
+
+export const logger = Logger.make((opts) => {
+  const extra = clean(opts.fiber.getRef(References.CurrentLogAnnotations))
+  const now = opts.date.getTime()
+  for (const [key, start] of opts.fiber.getRef(References.CurrentLogSpans)) {
+    extra[`logSpan.${key}`] = `${now - start}ms`
+  }
+  if (opts.cause.reasons.length > 0) {
+    extra.cause = Cause.pretty(opts.cause)
+  }
+
+  const svc = typeof extra.service === "string" ? extra.service : undefined
+  if (svc) delete extra.service
+  const log = svc ? Log.create({ service: svc }) : Log.Default
+  const msg = text(opts.message)
+
+  switch (opts.logLevel) {
+    case "Trace":
+    case "Debug":
+      return log.debug(msg, extra)
+    case "Warn":
+      return log.warn(msg, extra)
+    case "Error":
+    case "Fatal":
+      return log.error(msg, extra)
+    default:
+      return log.info(msg, extra)
+  }
+})
+
+export const layer = Logger.layer([logger], { mergeWithExisting: false })
+
+export const create = (base: Fields = {}): Handle => ({
+  debug: (msg, extra) => call((item) => Effect.logDebug(item), base, msg, extra),
+  info: (msg, extra) => call((item) => Effect.logInfo(item), base, msg, extra),
+  warn: (msg, extra) => call((item) => Effect.logWarning(item), base, msg, extra),
+  error: (msg, extra) => call((item) => Effect.logError(item), base, msg, extra),
+  with: (extra) => create({ ...base, ...extra }),
+})
diff --git a/packages/core/src/effect/memo-map.ts b/packages/core/src/effect/memo-map.ts
new file mode 100644
index 000000000..c797dbf42
--- /dev/null
+++ b/packages/core/src/effect/memo-map.ts
@@ -0,0 +1,3 @@
+import { Layer } from "effect"
+
+export const memoMap = Layer.makeMemoMapUnsafe()
diff --git a/packages/core/src/effect/observability.ts b/packages/core/src/effect/observability.ts
new file mode 100644
index 000000000..0203079ab
--- /dev/null
+++ b/packages/core/src/effect/observability.ts
@@ -0,0 +1,107 @@
+import { Effect, Layer, Logger } from "effect"
+import { FetchHttpClient } from "effect/unstable/http"
+import { OtlpLogger, OtlpSerialization } from "effect/unstable/observability"
+import * as EffectLogger from "./logger"
+import { Flag } from "../flag/flag"
+import { InstallationChannel, InstallationVersion } from "../installation/version"
+import { ensureProcessMetadata } from "../util/opencode-process"
+
+const base = Flag.OTEL_EXPORTER_OTLP_ENDPOINT
+export const enabled = !!base
+const processID = crypto.randomUUID()
+
+const headers = Flag.OTEL_EXPORTER_OTLP_HEADERS
+  ? Flag.OTEL_EXPORTER_OTLP_HEADERS.split(",").reduce(
+      (acc, x) => {
+        const [key, ...value] = x.split("=")
+        acc[key] = value.join("=")
+        return acc
+      },
+      {} as Record<string, string>,
+    )
+  : undefined
+
+export function resource(): { serviceName: string; serviceVersion: string; attributes: Record<string, string> } {
+  const processMetadata = ensureProcessMetadata("main")
+  const attributes: Record<string, string> = (() => {
+    const value = process.env.OTEL_RESOURCE_ATTRIBUTES
+    if (!value) return {}
+    try {
+      return Object.fromEntries(
+        value.split(",").map((entry) => {
+          const index = entry.indexOf("=")
+          if (index < 1) throw new Error("Invalid OTEL_RESOURCE_ATTRIBUTES entry")
+          return [decodeURIComponent(entry.slice(0, index)), decodeURIComponent(entry.slice(index + 1))]
+        }),
+      )
+    } catch {
+      return {}
+    }
+  })()
+
+  return {
+    serviceName: "opencode",
+    serviceVersion: InstallationVersion,
+    attributes: {
+      ...attributes,
+      "deployment.environment.name": InstallationChannel,
+      "opencode.client": Flag.OPENCODE_CLIENT,
+      "opencode.process_role": processMetadata.processRole,
+      "opencode.run_id": processMetadata.runID,
+      "service.instance.id": processID,
+    },
+  }
+}
+
+function logs() {
+  return Logger.layer(
+    [
+      EffectLogger.logger,
+      OtlpLogger.make({
+        url: `${base}/v1/logs`,
+        resource: resource(),
+        headers,
+      }),
+    ],
+    { mergeWithExisting: false },
+  ).pipe(Layer.provide(OtlpSerialization.layerJson), Layer.provide(FetchHttpClient.layer))
+}
+
+const traces = async () => {
+  const NodeSdk = await import("@effect/opentelemetry/NodeSdk")
+  const OTLP = await import("@opentelemetry/exporter-trace-otlp-http")
+  const SdkBase = await import("@opentelemetry/sdk-trace-base")
+
+  // @effect/opentelemetry creates a NodeTracerProvider but never calls
+  // register(), so the global @opentelemetry/api context manager stays
+  // as the no-op default. Non-Effect code (like the AI SDK) that calls
+  // tracer.startActiveSpan() relies on context.active() to find the
+  // parent span - without a real context manager every span starts a
+  // new trace. Registering AsyncLocalStorageContextManager fixes this.
+  const { AsyncLocalStorageContextManager } = await import("@opentelemetry/context-async-hooks")
+  const { context } = await import("@opentelemetry/api")
+  const mgr = new AsyncLocalStorageContextManager()
+  mgr.enable()
+  context.setGlobalContextManager(mgr)
+
+  return NodeSdk.layer(() => ({
+    resource: resource(),
+    spanProcessor: new SdkBase.BatchSpanProcessor(
+      new OTLP.OTLPTraceExporter({
+        url: `${base}/v1/traces`,
+        headers,
+      }),
+    ),
+  }))
+}
+
+export const layer = !base
+  ? EffectLogger.layer
+  : Layer.unwrap(
+      Effect.gen(function* () {
+        const trace = yield* Effect.promise(traces)
+        return Layer.mergeAll(trace, logs())
+      }),
+    )
+
+export const Observability = { enabled, layer }
diff --git a/packages/core/src/effect/runtime.ts b/packages/core/src/effect/runtime.ts
new file mode 100644
index 000000000..e4f682709
--- /dev/null
+++ b/packages/core/src/effect/runtime.ts
@@ -0,0 +1,21 @@
+import { Layer, type Context, ManagedRuntime, type Effect } from "effect"
+import { memoMap } from "./memo-map"
+import { Observability } from "./observability"
+
+export function makeRuntime<I, S, E>(service: Context.Service<I, S>, layer: Layer.Layer<I, E>) {
+  let rt: ManagedRuntime.ManagedRuntime<I, E> | undefined
+  const getRuntime = () =>
+    (rt ??= ManagedRuntime.make(Layer.provideMerge(layer, Observability.layer) as Layer.Layer<I, E>, {
+      memoMap,
+    }))
+
+  return {
+    runSync: <A, Err>(fn: (svc: S) => Effect.Effect<A, Err, I>) => getRuntime().runSync(service.use(fn)),
+    runPromiseExit: <A, Err>(fn: (svc: S) => Effect.Effect<A, Err, I>, options?: Effect.RunOptions) =>
+      getRuntime().runPromiseExit(service.use(fn), options),
+    runPromise: <A, Err>(fn: (svc: S) => Effect.Effect<A, Err, I>, options?: Effect.RunOptions) =>
+      getRuntime().runPromise(service.use(fn), options),
+    runFork: <A, Err>(fn: (svc: S) => Effect.Effect<A, Err, I>) => getRuntime().runFork(service.use(fn)),
+    runCallback: <A, Err>(fn: (svc: S) => Effect.Effect<A, Err, I>) => getRuntime().runCallback(service.use(fn)),
+  }
+}