diff --git a/core/stdlib/docs/intro.vue b/core/stdlib/docs/intro.vue
index 5d54ef1..f00243d 100644
--- a/core/stdlib/docs/intro.vue
+++ b/core/stdlib/docs/intro.vue
@@ -30,7 +30,7 @@ if (error) {
     <!-- Hero -->
     <div class="prose-docs">
       <h1>@robonen/stdlib</h1>
-      <p class="text-lg text-(--fg-muted)">
+      <p class="text-lg text-fg-muted">
         A platform-independent standard library of tools, utilities, and helpers for TypeScript —
         arrays, async, math, data structures, and patterns, all tree-shakeable and fully typed.
       </p>
@@ -48,30 +48,30 @@ if (error) {
 
     <!-- Feature highlights -->
     <div class="grid grid-cols-1 sm:grid-cols-2 gap-4">
-      <div class="rounded-lg border border-(--border) bg-(--bg-subtle) p-5">
-        <h3 class="text-sm font-semibold text-(--fg) mb-1.5">Fully typed</h3>
-        <p class="text-sm text-(--fg-muted) leading-relaxed">
+      <div class="rounded-lg border border-border bg-bg-subtle p-5">
+        <h3 class="text-sm font-semibold text-fg mb-1.5">Fully typed</h3>
+        <p class="text-sm text-fg-muted leading-relaxed">
           Generic signatures preserve element and key types end to end, so inference keeps
           working through <code>groupBy</code>, <code>partition</code>, <code>zip</code>, and friends.
         </p>
       </div>
-      <div class="rounded-lg border border-(--border) bg-(--bg-subtle) p-5">
-        <h3 class="text-sm font-semibold text-(--fg) mb-1.5">Zero dependencies</h3>
-        <p class="text-sm text-(--fg-muted) leading-relaxed">
+      <div class="rounded-lg border border-border bg-bg-subtle p-5">
+        <h3 class="text-sm font-semibold text-fg mb-1.5">Zero dependencies</h3>
+        <p class="text-sm text-fg-muted leading-relaxed">
           No transitive dependencies and no platform assumptions. The same code runs in Node,
           the browser, Deno, Bun, and edge runtimes.
         </p>
       </div>
-      <div class="rounded-lg border border-(--border) bg-(--bg-subtle) p-5">
-        <h3 class="text-sm font-semibold text-(--fg) mb-1.5">Tree-shakeable</h3>
-        <p class="text-sm text-(--fg-muted) leading-relaxed">
+      <div class="rounded-lg border border-border bg-bg-subtle p-5">
+        <h3 class="text-sm font-semibold text-fg mb-1.5">Tree-shakeable</h3>
+        <p class="text-sm text-fg-muted leading-relaxed">
           Each utility is a standalone export with no shared side effects. Import a single
           function and ship only that function.
         </p>
       </div>
-      <div class="rounded-lg border border-(--border) bg-(--bg-subtle) p-5">
-        <h3 class="text-sm font-semibold text-(--fg) mb-1.5">Batteries included</h3>
-        <p class="text-sm text-(--fg-muted) leading-relaxed">
+      <div class="rounded-lg border border-border bg-bg-subtle p-5">
+        <h3 class="text-sm font-semibold text-fg mb-1.5">Batteries included</h3>
+        <p class="text-sm text-fg-muted leading-relaxed">
           Beyond array and math helpers you get data structures
           (<code>Deque</code>, <code>BinaryHeap</code>, <code>LinkedList</code>) and patterns
           (<code>StateMachine</code>, <code>PubSub</code>, <code>Command</code>).
@@ -126,16 +126,16 @@ if (error) {
     </div>
 
     <!-- Where to next -->
-    <div class="rounded-lg border border-(--border) bg-(--bg-elevated) p-5">
-      <h2 class="text-base font-semibold text-(--fg) mb-2">Where to next</h2>
-      <p class="text-sm text-(--fg-muted) mb-3">
+    <div class="rounded-lg border border-border bg-bg-elevated p-5">
+      <h2 class="text-base font-semibold text-fg mb-2">Where to next</h2>
+      <p class="text-sm text-fg-muted mb-3">
         Browse the full API reference below, or jump straight to a popular utility:
       </p>
       <ul class="flex flex-wrap gap-2 m-0 p-0 list-none">
         <li>
           <NuxtLink
             to="/stdlib/group-by"
-            class="inline-flex items-center rounded-md border border-(--border) bg-(--bg-subtle) px-3 py-1.5 text-sm text-(--accent-text) hover:bg-(--bg-inset) focus:ring-(--ring)"
+            class="inline-flex items-center rounded-md border border-border bg-bg-subtle px-3 py-1.5 text-sm text-accent-text hover:bg-bg-inset focus:ring-ring"
           >
             groupBy
           </NuxtLink>
@@ -143,7 +143,7 @@ if (error) {
         <li>
           <NuxtLink
             to="/stdlib/try-it"
-            class="inline-flex items-center rounded-md border border-(--border) bg-(--bg-subtle) px-3 py-1.5 text-sm text-(--accent-text) hover:bg-(--bg-inset) focus:ring-(--ring)"
+            class="inline-flex items-center rounded-md border border-border bg-bg-subtle px-3 py-1.5 text-sm text-accent-text hover:bg-bg-inset focus:ring-ring"
           >
             tryIt
           </NuxtLink>
@@ -151,7 +151,7 @@ if (error) {
         <li>
           <NuxtLink
             to="/stdlib/retry"
-            class="inline-flex items-center rounded-md border border-(--border) bg-(--bg-subtle) px-3 py-1.5 text-sm text-(--accent-text) hover:bg-(--bg-inset) focus:ring-(--ring)"
+            class="inline-flex items-center rounded-md border border-border bg-bg-subtle px-3 py-1.5 text-sm text-accent-text hover:bg-bg-inset focus:ring-ring"
           >
             retry
           </NuxtLink>
@@ -159,7 +159,7 @@ if (error) {
         <li>
           <NuxtLink
             to="/stdlib/clamp"
-            class="inline-flex items-center rounded-md border border-(--border) bg-(--bg-subtle) px-3 py-1.5 text-sm text-(--accent-text) hover:bg-(--bg-inset) focus:ring-(--ring)"
+            class="inline-flex items-center rounded-md border border-border bg-bg-subtle px-3 py-1.5 text-sm text-accent-text hover:bg-bg-inset focus:ring-ring"
           >
             clamp
           </NuxtLink>
@@ -167,7 +167,7 @@ if (error) {
         <li>
           <NuxtLink
             to="/stdlib/debounce"
-            class="inline-flex items-center rounded-md border border-(--border) bg-(--bg-subtle) px-3 py-1.5 text-sm text-(--accent-text) hover:bg-(--bg-inset) focus:ring-(--ring)"
+            class="inline-flex items-center rounded-md border border-border bg-bg-subtle px-3 py-1.5 text-sm text-accent-text hover:bg-bg-inset focus:ring-ring"
           >
             debounce
           </NuxtLink>
diff --git a/core/stdlib/eslint.config.ts b/core/stdlib/eslint.config.ts
index e703f35..4440c10 100644
--- a/core/stdlib/eslint.config.ts
+++ b/core/stdlib/eslint.config.ts
@@ -1,3 +1,3 @@
-import { base, compose, imports, stylistic, typescript } from '@robonen/eslint';
+import { base, compose, imports, stylistic, tests, typescript } from '@robonen/eslint';
 
-export default compose(base, typescript, imports, stylistic);
+export default compose(base, typescript, imports, stylistic, tests);
diff --git a/core/stdlib/src/arrays/zip/index.ts b/core/stdlib/src/arrays/zip/index.ts
index 82abc8f..48b4120 100644
--- a/core/stdlib/src/arrays/zip/index.ts
+++ b/core/stdlib/src/arrays/zip/index.ts
@@ -22,7 +22,7 @@ export function zip<A, B>(a: A[], b: B[]): Array<[A, B]>;
 export function zip<A, B, C>(a: A[], b: B[], c: C[]): Array<[A, B, C]>;
 export function zip<A, B, C, D>(a: A[], b: B[], c: C[], d: D[]): Array<[A, B, C, D]>;
 export function zip<A, B, C, D, E>(a: A[], b: B[], c: C[], d: D[], e: E[]): Array<[A, B, C, D, E]>;
-export function zip(...arrays: any[][]): any[][] {
+export function zip(...arrays: unknown[][]): unknown[][] {
   if (arrays.length === 0)
     return [];
 
diff --git a/core/stdlib/src/async/pool/index.ts b/core/stdlib/src/async/pool/index.ts
index 9211d88..c73d1e0 100644
--- a/core/stdlib/src/async/pool/index.ts
+++ b/core/stdlib/src/async/pool/index.ts
@@ -6,7 +6,7 @@ export interface AsyncPoolOptions {
   signal?: AbortSignal;
 }
 
-interface PoolEntry<T = any> {
+interface PoolEntry<T = unknown> {
   task: (signal: AbortSignal) => Promise<T>;
   resolve: (value: T) => void;
   reject: (reason: unknown) => void;
@@ -115,7 +115,9 @@ export class AsyncPool {
       reject(this.signal.reason);
       return promise;
     }
-    const entry = { task, resolve, reject } as PoolEntry<T>;
+    // Stored in a homogeneous queue: the per-call T is erased to PoolEntry<unknown>.
+    // run() resolves/rejects with unknown values, so this is sound at runtime.
+    const entry = { task, resolve, reject } as unknown as PoolEntry;
     if (this.activeCount < this.limit) {
       this.run(entry);
     }
diff --git a/core/stdlib/src/async/retry/index.ts b/core/stdlib/src/async/retry/index.ts
index aab5724..d7f435b 100644
--- a/core/stdlib/src/async/retry/index.ts
+++ b/core/stdlib/src/async/retry/index.ts
@@ -11,13 +11,13 @@ export interface RetryOptions {
 export type RetryFunction<Return> = (
   args: {
     count: number;
-    stop: (error: any) => void;
+    stop: (error: unknown) => void;
   },
 ) => Promise<Return>;
 
 class RetryEarlyExitError {
-  cause: any;
-  constructor(cause: any) {
+  cause: unknown;
+  constructor(cause: unknown) {
     this.cause = cause;
   }
 }
@@ -62,7 +62,7 @@ export async function retry<Return>(
   const delayFn = isFunction(delay) ? delay : null;
   const delayMs = delayFn ? 0 : delay as number;
 
-  const stop = (error?: any): never => {
+  const stop = (error?: unknown): never => {
     throw new RetryEarlyExitError(error);
   };
 
diff --git a/core/stdlib/src/async/tryIt/index.ts b/core/stdlib/src/async/tryIt/index.ts
index 14f49a3..c304cf9 100644
--- a/core/stdlib/src/async/tryIt/index.ts
+++ b/core/stdlib/src/async/tryIt/index.ts
@@ -1,4 +1,4 @@
-export type TryItReturn<Return> = Return extends PromiseLike<any>
+export type TryItReturn<Return> = Return extends PromiseLike<unknown>
   ? Promise<{ error: Error; data: undefined } | { error: undefined; data: Awaited<Return> }>
   : { error: Error; data: undefined } | { error: undefined; data: Return };
 
@@ -7,11 +7,11 @@ function isThenable(value: unknown): value is PromiseLike<unknown> {
     && typeof (value as PromiseLike<unknown>).then === 'function';
 }
 
-function onResolve(data: any) {
+function onResolve(data: unknown) {
   return { error: undefined, data };
 }
 
-function onReject(error: any) {
+function onReject(error: unknown) {
   return { error, data: undefined };
 }
 
@@ -32,7 +32,7 @@ function onReject(error: any) {
  *
  * @since 0.0.3
  */
-export function tryIt<Args extends any[], Return>(
+export function tryIt<Args extends unknown[], Return>(
   fn: (...args: Args) => Return,
 ) {
   return (...args: Args): TryItReturn<Return> => {
diff --git a/core/stdlib/src/collections/get/index.ts b/core/stdlib/src/collections/get/index.ts
index a222f6b..94b0c52 100644
--- a/core/stdlib/src/collections/get/index.ts
+++ b/core/stdlib/src/collections/get/index.ts
@@ -7,7 +7,10 @@ export type ExtractFromObject<O extends Record<PropertyKey, unknown>, K>
       ? NonNullable<O>[K]
       : never;
 
-export type ExtractFromArray<A extends readonly any[], K>
+export type ExtractFromArray<A extends readonly unknown[], K>
+  // `any[]` (not `unknown[]`) is load-bearing: `any[] extends number[]` is true while
+  // `unknown[] extends number[]` is false. This distinguishes a general array (widen the
+  // element with `undefined`) from a fixed tuple (resolve the exact element at index K).
   = any[] extends A
     ? A extends ReadonlyArray<infer T>
       ? T | undefined
@@ -22,7 +25,7 @@ export type ExtractFromCollection<O, K>
     : K extends [infer Key, ...infer Rest]
       ? O extends Record<PropertyKey, unknown>
         ? ExtractFromCollection<ExtractFromObject<O, Key>, Rest>
-        : O extends readonly any[]
+        : O extends readonly unknown[]
           ? ExtractFromCollection<ExtractFromArray<O, Key>, Rest>
           : never
       : never;
@@ -46,7 +49,7 @@ export type Get<O, K> = ExtractFromCollection<O, Path<K>>;
  * @since 0.0.4
  */
 export function get<O extends Collection, K extends string>(obj: O, path: K): Get<O, K> | undefined {
-  let value: any = obj;
+  let value: unknown = obj;
   let start = 0;
 
   // Walk the path without allocating an intermediate array of segments.
@@ -58,9 +61,9 @@ export function get<O extends Collection, K extends string>(obj: O, path: K): Ge
     if (value === null || value === undefined)
       return undefined;
 
-    value = value[path.slice(start, i)];
+    value = (value as Record<string, unknown>)[path.slice(start, i)];
     start = i + 1;
   }
 
-  return value;
+  return value as Get<O, K> | undefined;
 }
diff --git a/core/stdlib/src/collections/set/index.ts b/core/stdlib/src/collections/set/index.ts
index d2a7f61..f829df2 100644
--- a/core/stdlib/src/collections/set/index.ts
+++ b/core/stdlib/src/collections/set/index.ts
@@ -27,7 +27,7 @@ export function set<O extends Collection>(obj: O, path: string, value: unknown):
 
   const keys = path.split('.');
   const lastKey = keys[keys.length - 1]!;
-  let current: any = obj;
+  let current = obj as Record<PropertyKey, unknown>;
 
   for (let i = 0; i < keys.length - 1; i++) {
     const key = keys[i]!;
@@ -38,7 +38,7 @@ export function set<O extends Collection>(obj: O, path: string, value: unknown):
     if (next === null || typeof next !== 'object')
       current[key] = NUMERIC_SEGMENT.test(keys[i + 1]!) ? [] : {};
 
-    current = current[key];
+    current = current[key] as Record<PropertyKey, unknown>;
   }
 
   current[lastKey] = value;
diff --git a/core/stdlib/src/comparators/isEqual/index.ts b/core/stdlib/src/comparators/isEqual/index.ts
index 3d9256f..43e50d5 100644
--- a/core/stdlib/src/comparators/isEqual/index.ts
+++ b/core/stdlib/src/comparators/isEqual/index.ts
@@ -1,4 +1,4 @@
-function equals(a: any, b: any, seen: WeakMap<object, unknown>): boolean {
+function equals(a: unknown, b: unknown, seen: WeakMap<object, unknown>): boolean {
   if (a === b)
     return true;
 
@@ -65,7 +65,7 @@ function equals(a: any, b: any, seen: WeakMap<object, unknown>): boolean {
     return false;
 
   for (const key of aKeys) {
-    if (!Object.prototype.hasOwnProperty.call(b, key) || !equals(a[key], b[key], seen))
+    if (!Object.prototype.hasOwnProperty.call(b, key) || !equals((a as Record<string, unknown>)[key], (b as Record<string, unknown>)[key], seen))
       return false;
   }
 
diff --git a/core/stdlib/src/functions/compose/index.ts b/core/stdlib/src/functions/compose/index.ts
index d449744..1d2a1cc 100644
--- a/core/stdlib/src/functions/compose/index.ts
+++ b/core/stdlib/src/functions/compose/index.ts
@@ -14,15 +14,15 @@ import type { AnyFunction } from '../../types';
  *
  * @since 0.0.10
  */
-export function compose<A extends any[], B>(ab: (...a: A) => B): (...a: A) => B;
-export function compose<A extends any[], B, C>(bc: (b: B) => C, ab: (...a: A) => B): (...a: A) => C;
-export function compose<A extends any[], B, C, D>(cd: (c: C) => D, bc: (b: B) => C, ab: (...a: A) => B): (...a: A) => D;
-export function compose<A extends any[], B, C, D, E>(de: (d: D) => E, cd: (c: C) => D, bc: (b: B) => C, ab: (...a: A) => B): (...a: A) => E;
-export function compose<A extends any[], B, C, D, E, F>(ef: (e: E) => F, de: (d: D) => E, cd: (c: C) => D, bc: (b: B) => C, ab: (...a: A) => B): (...a: A) => F;
-export function compose<A extends any[], B, C, D, E, F, G>(fg: (f: F) => G, ef: (e: E) => F, de: (d: D) => E, cd: (c: C) => D, bc: (b: B) => C, ab: (...a: A) => B): (...a: A) => G;
-export function compose<A extends any[], B, C, D, E, F, G, H>(gh: (g: G) => H, fg: (f: F) => G, ef: (e: E) => F, de: (d: D) => E, cd: (c: C) => D, bc: (b: B) => C, ab: (...a: A) => B): (...a: A) => H;
+export function compose<A extends unknown[], B>(ab: (...a: A) => B): (...a: A) => B;
+export function compose<A extends unknown[], B, C>(bc: (b: B) => C, ab: (...a: A) => B): (...a: A) => C;
+export function compose<A extends unknown[], B, C, D>(cd: (c: C) => D, bc: (b: B) => C, ab: (...a: A) => B): (...a: A) => D;
+export function compose<A extends unknown[], B, C, D, E>(de: (d: D) => E, cd: (c: C) => D, bc: (b: B) => C, ab: (...a: A) => B): (...a: A) => E;
+export function compose<A extends unknown[], B, C, D, E, F>(ef: (e: E) => F, de: (d: D) => E, cd: (c: C) => D, bc: (b: B) => C, ab: (...a: A) => B): (...a: A) => F;
+export function compose<A extends unknown[], B, C, D, E, F, G>(fg: (f: F) => G, ef: (e: E) => F, de: (d: D) => E, cd: (c: C) => D, bc: (b: B) => C, ab: (...a: A) => B): (...a: A) => G;
+export function compose<A extends unknown[], B, C, D, E, F, G, H>(gh: (g: G) => H, fg: (f: F) => G, ef: (e: E) => F, de: (d: D) => E, cd: (c: C) => D, bc: (b: B) => C, ab: (...a: A) => B): (...a: A) => H;
 export function compose(...fns: AnyFunction[]): AnyFunction {
-  return function (this: unknown, ...args: any[]) {
+  return function (this: unknown, ...args: unknown[]) {
     const last = fns.length - 1;
 
     if (last < 0)
diff --git a/core/stdlib/src/functions/pipe/index.ts b/core/stdlib/src/functions/pipe/index.ts
index 1629b19..6bf6379 100644
--- a/core/stdlib/src/functions/pipe/index.ts
+++ b/core/stdlib/src/functions/pipe/index.ts
@@ -14,15 +14,15 @@ import type { AnyFunction } from '../../types';
  *
  * @since 0.0.10
  */
-export function pipe<A extends any[], B>(ab: (...a: A) => B): (...a: A) => B;
-export function pipe<A extends any[], B, C>(ab: (...a: A) => B, bc: (b: B) => C): (...a: A) => C;
-export function pipe<A extends any[], B, C, D>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D): (...a: A) => D;
-export function pipe<A extends any[], B, C, D, E>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E): (...a: A) => E;
-export function pipe<A extends any[], B, C, D, E, F>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F): (...a: A) => F;
-export function pipe<A extends any[], B, C, D, E, F, G>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G): (...a: A) => G;
-export function pipe<A extends any[], B, C, D, E, F, G, H>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H): (...a: A) => H;
+export function pipe<A extends unknown[], B>(ab: (...a: A) => B): (...a: A) => B;
+export function pipe<A extends unknown[], B, C>(ab: (...a: A) => B, bc: (b: B) => C): (...a: A) => C;
+export function pipe<A extends unknown[], B, C, D>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D): (...a: A) => D;
+export function pipe<A extends unknown[], B, C, D, E>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E): (...a: A) => E;
+export function pipe<A extends unknown[], B, C, D, E, F>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F): (...a: A) => F;
+export function pipe<A extends unknown[], B, C, D, E, F, G>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G): (...a: A) => G;
+export function pipe<A extends unknown[], B, C, D, E, F, G, H>(ab: (...a: A) => B, bc: (b: B) => C, cd: (c: C) => D, de: (d: D) => E, ef: (e: E) => F, fg: (f: F) => G, gh: (g: G) => H): (...a: A) => H;
 export function pipe(...fns: AnyFunction[]): AnyFunction {
-  return function (this: unknown, ...args: any[]) {
+  return function (this: unknown, ...args: unknown[]) {
     if (fns.length === 0)
       return args[0];
 
diff --git a/core/stdlib/src/patterns/behavioral/StateMachine/async.ts b/core/stdlib/src/patterns/behavioral/StateMachine/async.ts
index 13b6a63..05bfb8e 100644
--- a/core/stdlib/src/patterns/behavioral/StateMachine/async.ts
+++ b/core/stdlib/src/patterns/behavioral/StateMachine/async.ts
@@ -124,6 +124,9 @@ export function createAsyncMachine<
 export function createAsyncMachine(config: {
   initial: string;
   context?: unknown;
+  // Overload-implementation signature: the typed overloads above expose the real
+  // per-context API; `any` here accepts every concrete `AsyncStateNodeConfig<C>`
+  // (contravariant in `C`, so `unknown` would reject them).
   states: Record<string, AsyncStateNodeConfig<any>>;
 }): AsyncStateMachine {
   return new AsyncStateMachine(
diff --git a/core/stdlib/src/patterns/behavioral/StateMachine/sync.ts b/core/stdlib/src/patterns/behavioral/StateMachine/sync.ts
index 3c9c8c3..ac66fd6 100644
--- a/core/stdlib/src/patterns/behavioral/StateMachine/sync.ts
+++ b/core/stdlib/src/patterns/behavioral/StateMachine/sync.ts
@@ -125,6 +125,9 @@ export function createMachine<
 export function createMachine(config: {
   initial: string;
   context?: unknown;
+  // Overload-implementation signature: the typed overloads above expose the real
+  // per-context API; `any` here accepts every concrete `SyncStateNodeConfig<C>`
+  // (contravariant in `C`, so `unknown` would reject them).
   states: Record<string, SyncStateNodeConfig<any>>;
 }): StateMachine {
   return new StateMachine(
diff --git a/core/stdlib/src/patterns/behavioral/StateMachine/types.ts b/core/stdlib/src/patterns/behavioral/StateMachine/types.ts
index 6b57492..a4ef161 100644
--- a/core/stdlib/src/patterns/behavioral/StateMachine/types.ts
+++ b/core/stdlib/src/patterns/behavioral/StateMachine/types.ts
@@ -58,7 +58,7 @@ export type AsyncStateNodeConfig<Context> = StateNodeConfig<Context, MaybePromis
 export type ExtractStates<T> = keyof T & string;
 
 export type ExtractEvents<T> = {
-  [K in keyof T]: T[K] extends { readonly on?: Readonly<Record<infer E extends string, any>> }
+  [K in keyof T]: T[K] extends { readonly on?: Readonly<Record<infer E extends string, unknown>> }
     ? E
     : never;
 }[keyof T];
diff --git a/core/stdlib/src/structs/BinaryHeap/index.ts b/core/stdlib/src/structs/BinaryHeap/index.ts
index 60e7449..29b56f1 100644
--- a/core/stdlib/src/structs/BinaryHeap/index.ts
+++ b/core/stdlib/src/structs/BinaryHeap/index.ts
@@ -14,7 +14,7 @@ export interface BinaryHeapOptions<T> {
  * @param {number} b Second element
  * @returns {number} Negative if a < b, positive if a > b, zero if equal
  */
-const defaultComparator: Comparator<any> = (a: number, b: number) => a - b;
+const defaultComparator: Comparator<number> = (a: number, b: number) => a - b;
 
 /**
  * @name BinaryHeap
@@ -49,7 +49,8 @@ export class BinaryHeap<T> implements BinaryHeapLike<T> {
      * @param {BinaryHeapOptions<T>} [options] Heap configuration
      */
   constructor(initialValues?: T[] | T, options?: BinaryHeapOptions<T>) {
-    this.comparator = options?.comparator ?? defaultComparator;
+    // Numeric default; cast bridges it to the caller's `T` when no comparator is given.
+    this.comparator = options?.comparator ?? (defaultComparator as Comparator<T>);
 
     if (initialValues !== null && initialValues !== undefined) {
       const items = isArray(initialValues) ? initialValues : [initialValues];
diff --git a/core/stdlib/src/types/js/casts.ts b/core/stdlib/src/types/js/casts.ts
index b6c7f08..ce6d347 100644
--- a/core/stdlib/src/types/js/casts.ts
+++ b/core/stdlib/src/types/js/casts.ts
@@ -3,9 +3,9 @@
  * @category Types
  * @description To string any value
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {string}
  *
  * @since 0.0.2
  */
-export const toString = (value: any): string => Object.prototype.toString.call(value);
+export const toString = (value: unknown): string => Object.prototype.toString.call(value);
diff --git a/core/stdlib/src/types/js/complex.test.ts b/core/stdlib/src/types/js/complex.test.ts
index 9e70f26..a63f019 100644
--- a/core/stdlib/src/types/js/complex.test.ts
+++ b/core/stdlib/src/types/js/complex.test.ts
@@ -38,7 +38,6 @@ describe('complex', () => {
     });
 
     it('true for class instances and null-prototype objects', () => {
-      // eslint-disable-next-line @typescript-eslint/no-extraneous-class -- fixture for the instance check
       class Foo {}
 
       expect(isObject(new Foo())).toBe(true);
diff --git a/core/stdlib/src/types/js/complex.ts b/core/stdlib/src/types/js/complex.ts
index cdd195a..da23d5b 100644
--- a/core/stdlib/src/types/js/complex.ts
+++ b/core/stdlib/src/types/js/complex.ts
@@ -5,117 +5,117 @@ import { toString } from './casts';
  * @category Types
  * @description Check if a value is an array
  *
- * @param {any} value
- * @returns {value is any[]}
+ * @param {unknown} value
+ * @returns {value is T[]}
  *
  * @since 0.0.2
  */
-export const isArray = (value: any): value is any[] => Array.isArray(value);
+export const isArray = <T = unknown>(value: unknown): value is T[] => Array.isArray(value);
 
 /**
  * @name isObject
  * @category Types
  * @description Check if a value is an object
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {value is object}
  *
  * @since 0.0.2
  */
-export const isObject = (value: any): value is object => toString(value) === '[object Object]';
+export const isObject = (value: unknown): value is object => toString(value) === '[object Object]';
 
 /**
  * @name isRegExp
  * @category Types
  * @description Check if a value is a regexp
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {value is RegExp}
  *
  * @since 0.0.2
  */
-export const isRegExp = (value: any): value is RegExp => toString(value) === '[object RegExp]';
+export const isRegExp = (value: unknown): value is RegExp => toString(value) === '[object RegExp]';
 
 /**
  * @name isDate
  * @category Types
  * @description Check if a value is a date
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {value is Date}
  *
  * @since 0.0.2
  */
-export const isDate = (value: any): value is Date => toString(value) === '[object Date]';
+export const isDate = (value: unknown): value is Date => toString(value) === '[object Date]';
 
 /**
  * @name isError
  * @category Types
  * @description Check if a value is an error
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {value is Error}
  *
  * @since 0.0.2
  */
-export const isError = (value: any): value is Error => toString(value) === '[object Error]';
+export const isError = (value: unknown): value is Error => toString(value) === '[object Error]';
 
 /**
  * @name isPromise
  * @category Types
  * @description Check if a value is a promise
  *
- * @param {any} value
- * @returns {value is Promise<any>}
+ * @param {unknown} value
+ * @returns {value is Promise<unknown>}
  *
  * @since 0.0.2
  */
-export const isPromise = (value: any): value is Promise<any> => toString(value) === '[object Promise]';
+export const isPromise = (value: unknown): value is Promise<unknown> => toString(value) === '[object Promise]';
 
 /**
  * @name isMap
  * @category Types
  * @description Check if a value is a map
  *
- * @param {any} value
- * @returns {value is Map<any, any>}
+ * @param {unknown} value
+ * @returns {value is Map<unknown, unknown>}
  *
  * @since 0.0.2
  */
-export const isMap = (value: any): value is Map<any, any> => toString(value) === '[object Map]';
+export const isMap = (value: unknown): value is Map<unknown, unknown> => toString(value) === '[object Map]';
 
 /**
  * @name isSet
  * @category Types
  * @description Check if a value is a set
  *
- * @param {any} value
- * @returns {value is Set<any>}
+ * @param {unknown} value
+ * @returns {value is Set<unknown>}
  *
  * @since 0.0.2
  */
-export const isSet = (value: any): value is Set<any> => toString(value) === '[object Set]';
+export const isSet = (value: unknown): value is Set<unknown> => toString(value) === '[object Set]';
 
 /**
  * @name isWeakMap
  * @category Types
  * @description Check if a value is a weakmap
  *
- * @param {any} value
- * @returns {value is WeakMap<object, any>}
+ * @param {unknown} value
+ * @returns {value is WeakMap<object, unknown>}
  *
  * @since 0.0.2
  */
-export const isWeakMap = (value: any): value is WeakMap<object, any> => toString(value) === '[object WeakMap]';
+export const isWeakMap = (value: unknown): value is WeakMap<object, unknown> => toString(value) === '[object WeakMap]';
 
 /**
  * @name isWeakSet
  * @category Types
  * @description Check if a value is a weakset
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {value is WeakSet<object>}
  *
  * @since 0.0.2
  */
-export const isWeakSet = (value: any): value is WeakSet<object> => toString(value) === '[object WeakSet]';
+export const isWeakSet = (value: unknown): value is WeakSet<object> => toString(value) === '[object WeakSet]';
diff --git a/core/stdlib/src/types/js/primitives.ts b/core/stdlib/src/types/js/primitives.ts
index 8e585e0..acfb793 100644
--- a/core/stdlib/src/types/js/primitives.ts
+++ b/core/stdlib/src/types/js/primitives.ts
@@ -3,93 +3,94 @@
  * @category Types
  * @description Check if a value is a boolean
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {value is boolean}
  *
  * @since 0.0.2
  */
-export const isBoolean = (value: any): value is boolean => typeof value === 'boolean';
+export const isBoolean = (value: unknown): value is boolean => typeof value === 'boolean';
 
 /**
  * @name isFunction
  * @category Types
  * @description Check if a value is a function
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {value is Function}
  *
  * @since 0.0.2
  */
-export const isFunction = <T extends (...args: any[]) => any>(value: any): value is T => typeof value === 'function';
+// `(...args: any[]) => any` is the idiomatic "any function" constraint here; `unknown` would reject legitimate function shapes at call sites.
+export const isFunction = <T extends (...args: any[]) => any>(value: unknown): value is T => typeof value === 'function';
 
 /**
  * @name isNumber
  * @category Types
  * @description Check if a value is a number
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {value is number}
  *
  * @since 0.0.2
  */
-export const isNumber = (value: any): value is number => typeof value === 'number';
+export const isNumber = (value: unknown): value is number => typeof value === 'number';
 
 /**
  * @name isBigInt
  * @category Types
  * @description Check if a value is a bigint
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {value is bigint}
  *
  * @since 0.0.2
  */
-export const isBigInt = (value: any): value is bigint => typeof value === 'bigint';
+export const isBigInt = (value: unknown): value is bigint => typeof value === 'bigint';
 
 /**
  * @name isString
  * @category Types
  * @description Check if a value is a string
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {value is string}
  *
  * @since 0.0.2
  */
-export const isString = (value: any): value is string => typeof value === 'string';
+export const isString = (value: unknown): value is string => typeof value === 'string';
 
 /**
  * @name isSymbol
  * @category Types
  * @description Check if a value is a symbol
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {value is symbol}
  *
  * @since 0.0.2
  */
-export const isSymbol = (value: any): value is symbol => typeof value === 'symbol';
+export const isSymbol = (value: unknown): value is symbol => typeof value === 'symbol';
 
 /**
  * @name isUndefined
  * @category Types
  * @description Check if a value is a undefined
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {value is undefined}
  *
  * @since 0.0.2
  */
-export const isUndefined = (value: any): value is undefined => value === undefined;
+export const isUndefined = (value: unknown): value is undefined => value === undefined;
 
 /**
  * @name isNull
  * @category Types
  * @description Check if a value is a null
  *
- * @param {any} value
+ * @param {unknown} value
  * @returns {value is null}
  *
  * @since 0.0.2
  */
-export const isNull = (value: any): value is null => value === null;
+export const isNull = (value: unknown): value is null => value === null;
diff --git a/core/stdlib/src/types/ts/collections.ts b/core/stdlib/src/types/ts/collections.ts
index dcec15b..cc2759d 100644
--- a/core/stdlib/src/types/ts/collections.ts
+++ b/core/stdlib/src/types/ts/collections.ts
@@ -1,7 +1,10 @@
 /**
  * A collection definition
  */
-export type Collection = Record<PropertyKey, any> | any[];
+// `any[]` is kept (not `unknown[]`): as the `O extends Collection` constraint in `get`/`set`,
+// `unknown[]` would reject arrays whose elements sit in contravariant positions (e.g. the
+// `CircularBuffer<PoolEntry>` used by `async/pool`), breaking compilation outside this file.
+export type Collection = Record<PropertyKey, unknown> | any[];
 
 /**
  * Parse a collection path string into an array of keys
diff --git a/core/stdlib/src/types/ts/function.ts b/core/stdlib/src/types/ts/function.ts
index 998fdc5..5ab6b45 100644
--- a/core/stdlib/src/types/ts/function.ts
+++ b/core/stdlib/src/types/ts/function.ts
@@ -1,6 +1,8 @@
 /**
  * Any function
  */
+// `(...args: any[]) => any` is the idiomatic "any function" constraint; `unknown`
+// would reject legitimate function shapes when used as `T extends AnyFunction`.
 export type AnyFunction = (...args: any[]) => any;
 
 /**