diff --git a/.agents/skills/create-adapter/SKILL.md b/.agents/skills/create-adapter/SKILL.md
index 0cfdf11..847d9b7 100644
--- a/.agents/skills/create-adapter/SKILL.md
+++ b/.agents/skills/create-adapter/SKILL.md
@@ -51,7 +51,7 @@ Read [references/adapter-template.md](references/adapter-template.md) for the fu
 Key architecture rules:
 
 1. **Config interface** -- service-specific fields (API key, endpoint, etc.) plus optional `timeout?: number`
-2. **`getRuntimeConfig()` helper** -- dynamic `require('nitropack/runtime')` wrapped in try/catch
+2. **`getRuntimeConfig()`** -- import from `./_utils` (shared helper, do NOT redefine locally)
 3. **Config priority** (highest to lowest):
    - Overrides passed to `create{Name}Drain()`
    - `runtimeConfig.evlog.{name}`
diff --git a/.agents/skills/create-adapter/references/adapter-template.md b/.agents/skills/create-adapter/references/adapter-template.md
index 4e9f796..eb6e1ec 100644
--- a/.agents/skills/create-adapter/references/adapter-template.md
+++ b/.agents/skills/create-adapter/references/adapter-template.md
@@ -6,6 +6,7 @@ Replace `{Name}`, `{name}`, and `{NAME}` with the actual service name.
 
 ```typescript
 import type { DrainContext, WideEvent } from '../types'
+import { getRuntimeConfig } from './_utils'
 
 // --- 1. Config Interface ---
 // Define all service-specific configuration fields.
@@ -45,23 +46,7 @@ export function to{Name}Event(event: WideEvent): {Name}Event {
   }
 }
 
-// --- 3. Runtime Config Helper ---
-// Dynamic require to avoid bundling issues outside Nitro.
-// Returns undefined when not in a Nitro context.
-function getRuntimeConfig(): {
-  evlog?: { {name}?: Partial<{Name}Config> }
-  {name}?: Partial<{Name}Config>
-} | undefined {
-  try {
-    // eslint-disable-next-line @typescript-eslint/no-require-imports
-    const { useRuntimeConfig } = require('nitropack/runtime')
-    return useRuntimeConfig()
-  } catch {
-    return undefined
-  }
-}
-
-// --- 4. Factory Function ---
+// --- 3. Factory Function ---
 // Returns a drain function that resolves config at call time.
 // Config priority: overrides > runtimeConfig.evlog.{name} > runtimeConfig.{name} > env vars
 
diff --git a/bun.lock b/bun.lock
index 409efd2..5cdd598 100644
--- a/bun.lock
+++ b/bun.lock
@@ -50,9 +50,6 @@
     "packages/evlog": {
       "name": "evlog",
       "version": "1.6.0",
-      "dependencies": {
-        "defu": "^6.1.4",
-      },
       "devDependencies": {
         "@nuxt/devtools": "^3.1.1",
         "@nuxt/schema": "^4.3.1",
diff --git a/packages/evlog/package.json b/packages/evlog/package.json
index 4c8caf6..c38608a 100644
--- a/packages/evlog/package.json
+++ b/packages/evlog/package.json
@@ -101,9 +101,6 @@
     "test:coverage": "vitest run --coverage",
     "typecheck": "echo 'Typecheck handled by build'"
   },
-  "dependencies": {
-    "defu": "^6.1.4"
-  },
   "devDependencies": {
     "@nuxt/devtools": "^3.1.1",
     "@nuxt/schema": "^4.3.1",
diff --git a/packages/evlog/src/adapters/_utils.ts b/packages/evlog/src/adapters/_utils.ts
new file mode 100644
index 0000000..3812227
--- /dev/null
+++ b/packages/evlog/src/adapters/_utils.ts
@@ -0,0 +1,13 @@
+/**
+ * Try to get runtime config from Nitro/Nuxt environment.
+ * Returns undefined if not in a Nitro context.
+ */
+export function getRuntimeConfig(): Record<string, unknown> | undefined {
+  try {
+    // eslint-disable-next-line @typescript-eslint/no-require-imports
+    const { useRuntimeConfig } = require('nitropack/runtime')
+    return useRuntimeConfig()
+  } catch {
+    return undefined
+  }
+}
diff --git a/packages/evlog/src/adapters/axiom.ts b/packages/evlog/src/adapters/axiom.ts
index b8bae94..495e041 100644
--- a/packages/evlog/src/adapters/axiom.ts
+++ b/packages/evlog/src/adapters/axiom.ts
@@ -1,4 +1,5 @@
 import type { DrainContext, WideEvent } from '../types'
+import { getRuntimeConfig } from './_utils'
 
 export interface AxiomConfig {
   /** Axiom dataset name */
@@ -13,21 +14,6 @@ export interface AxiomConfig {
   timeout?: number
 }
 
-/**
- * Try to get runtime config from Nitro/Nuxt environment.
- * Returns undefined if not in a Nitro context.
- */
-function getRuntimeConfig(): { evlog?: { axiom?: Partial<AxiomConfig> }, axiom?: Partial<AxiomConfig> } | undefined {
-  try {
-    // Dynamic import to avoid bundling issues when not in Nitro
-    // eslint-disable-next-line @typescript-eslint/no-require-imports
-    const { useRuntimeConfig } = require('nitropack/runtime')
-    return useRuntimeConfig()
-  } catch {
-    return undefined
-  }
-}
-
 /**
  * Create a drain function for sending logs to Axiom.
  *
diff --git a/packages/evlog/src/adapters/otlp.ts b/packages/evlog/src/adapters/otlp.ts
index 49c44a4..b9849b2 100644
--- a/packages/evlog/src/adapters/otlp.ts
+++ b/packages/evlog/src/adapters/otlp.ts
@@ -1,4 +1,5 @@
 import type { DrainContext, LogLevel, WideEvent } from '../types'
+import { getRuntimeConfig } from './_utils'
 
 export interface OTLPConfig {
   /** OTLP HTTP endpoint (e.g., http://localhost:4318) */
@@ -70,21 +71,6 @@ const SEVERITY_TEXT_MAP: Record<LogLevel, string> = {
   error: 'ERROR',
 }
 
-/**
- * Try to get runtime config from Nitro/Nuxt environment.
- * Returns undefined if not in a Nitro context.
- */
-function getRuntimeConfig(): { evlog?: { otlp?: Partial<OTLPConfig> }, otlp?: Partial<OTLPConfig> } | undefined {
-  try {
-    // Dynamic import to avoid bundling issues when not in Nitro
-    // eslint-disable-next-line @typescript-eslint/no-require-imports
-    const { useRuntimeConfig } = require('nitropack/runtime')
-    return useRuntimeConfig()
-  } catch {
-    return undefined
-  }
-}
-
 /**
  * Convert a value to OTLP attribute value format.
  */
diff --git a/packages/evlog/src/adapters/posthog.ts b/packages/evlog/src/adapters/posthog.ts
index c498b8a..2966232 100644
--- a/packages/evlog/src/adapters/posthog.ts
+++ b/packages/evlog/src/adapters/posthog.ts
@@ -1,4 +1,5 @@
 import type { DrainContext, WideEvent } from '../types'
+import { getRuntimeConfig } from './_utils'
 
 export interface PostHogConfig {
   /** PostHog project API key */
@@ -21,21 +22,6 @@ export interface PostHogEvent {
   properties: Record<string, unknown>
 }
 
-/**
- * Try to get runtime config from Nitro/Nuxt environment.
- * Returns undefined if not in a Nitro context.
- */
-function getRuntimeConfig(): { evlog?: { posthog?: Partial<PostHogConfig> }, posthog?: Partial<PostHogConfig> } | undefined {
-  try {
-    // Dynamic import to avoid bundling issues when not in Nitro
-    // eslint-disable-next-line @typescript-eslint/no-require-imports
-    const { useRuntimeConfig } = require('nitropack/runtime')
-    return useRuntimeConfig()
-  } catch {
-    return undefined
-  }
-}
-
 /**
  * Convert a WideEvent to a PostHog event format.
  */
diff --git a/packages/evlog/src/adapters/sentry.ts b/packages/evlog/src/adapters/sentry.ts
index 8c6e44d..45f765b 100644
--- a/packages/evlog/src/adapters/sentry.ts
+++ b/packages/evlog/src/adapters/sentry.ts
@@ -1,4 +1,5 @@
 import type { DrainContext, LogLevel, WideEvent } from '../types'
+import { getRuntimeConfig } from './_utils'
 
 export interface SentryConfig {
   /** Sentry DSN */
@@ -45,21 +46,6 @@ const SEVERITY_MAP: Record<LogLevel, number> = {
   error: 17,
 }
 
-/**
- * Try to get runtime config from Nitro/Nuxt environment.
- * Returns undefined if not in a Nitro context.
- */
-function getRuntimeConfig(): { evlog?: { sentry?: Partial<SentryConfig> }, sentry?: Partial<SentryConfig> } | undefined {
-  try {
-    // Dynamic import to avoid bundling issues when not in Nitro
-    // eslint-disable-next-line @typescript-eslint/no-require-imports
-    const { useRuntimeConfig } = require('nitropack/runtime')
-    return useRuntimeConfig()
-  } catch {
-    return undefined
-  }
-}
-
 function parseSentryDsn(dsn: string): SentryDsnParts {
   const url = new URL(dsn)
   const publicKey = url.username
diff --git a/packages/evlog/src/logger.ts b/packages/evlog/src/logger.ts
index 4e997d2..e8988c2 100644
--- a/packages/evlog/src/logger.ts
+++ b/packages/evlog/src/logger.ts
@@ -1,7 +1,24 @@
-import { defu } from 'defu'
 import type { EnvironmentContext, Log, LogLevel, LoggerConfig, RequestLogger, RequestLoggerOptions, SamplingConfig, TailSamplingContext, WideEvent } from './types'
 import { colors, detectEnvironment, formatDuration, getConsoleMethod, getLevelColor, isDev, matchesPattern } from './utils'
 
+function isPlainObject(val: unknown): val is Record<string, unknown> {
+  return val !== null && typeof val === 'object' && !Array.isArray(val)
+}
+
+function deepDefaults(base: Record<string, unknown>, defaults: Record<string, unknown>): Record<string, unknown> {
+  const result = { ...base }
+  for (const key in defaults) {
+    const baseVal = result[key]
+    const defaultVal = defaults[key]
+    if (baseVal === undefined || baseVal === null) {
+      result[key] = defaultVal
+    } else if (isPlainObject(baseVal) && isPlainObject(defaultVal)) {
+      result[key] = deepDefaults(baseVal, defaultVal)
+    }
+  }
+  return result
+}
+
 let globalEnv: EnvironmentContext = {
   service: 'app',
   environment: 'development',
@@ -221,7 +238,7 @@ export function createRequestLogger(options: RequestLoggerOptions = {}): Request
 
   return {
     set<T extends Record<string, unknown>>(data: T): void {
-      context = defu(data, context) as Record<string, unknown>
+      context = deepDefaults(data, context) as Record<string, unknown>
     },
 
     error(error: Error | string, errorContext?: Record<string, unknown>): void {
@@ -236,7 +253,7 @@ export function createRequestLogger(options: RequestLoggerOptions = {}): Request
           stack: err.stack,
         },
       }
-      context = defu(errorData, context) as Record<string, unknown>
+      context = deepDefaults(errorData, context) as Record<string, unknown>
     },
 
     emit(overrides?: Record<string, unknown> & { _forceKeep?: boolean }): WideEvent | null {