diff --git a/packages/adapters/src/chalk/stress.test.ts b/packages/adapters/src/chalk/stress.test.ts
new file mode 100644
index 000000000..bc56f0798
--- /dev/null
+++ b/packages/adapters/src/chalk/stress.test.ts
@@ -0,0 +1,136 @@
+// packages/adapters/src/chalk/stress.test.ts
+// Stress tests for chalk adapter under high-volume output.
+
+import { describe, it, expect, afterEach } from 'vitest';
+import { chalkToTermUI } from './index.js';
+
+function buildAnsiString(sequence: string, text: string): string {
+    return `${sequence}${text}\x1B[0m`;
+}
+
+const MIXED_SEQUENCES = [
+    '\x1B[31m',  // red
+    '\x1B[32m',  // green
+    '\x1B[33m',  // yellow
+    '\x1B[34m',  // blue
+    '\x1B[35m',  // magenta
+    '\x1B[36m',  // cyan
+    '\x1B[1m',   // bold
+    '\x1B[4m',   // underline
+    '\x1B[7m',   // reverse
+    '\x1B[9m',   // strikethrough
+];
+
+function mixedAnsi(text: string): string {
+    let result = text;
+    for (const seq of MIXED_SEQUENCES) {
+        result = buildAnsiString(seq, result);
+    }
+    return result;
+}
+
+describe('chalk adapter stress tests', () => {
+    afterEach(() => {
+        delete process.env.NO_COLOR;
+    });
+
+    it('handles 1,000 rapid successive calls without error', () => {
+        const originalNoColor = process.env.NO_COLOR;
+        delete process.env.NO_COLOR;
+
+        const texts = Array.from({ length: 1000 }, (_, i) => `line-${i}`);
+        const ansiTexts = texts.map((t, i) => {
+            const seq = MIXED_SEQUENCES[i % MIXED_SEQUENCES.length];
+            return buildAnsiString(seq, t);
+        });
+
+        expect(() => {
+            for (const input of ansiTexts) {
+                chalkToTermUI(input);
+            }
+        }).not.toThrow();
+    });
+
+    it('handles 5,000 rapid successive calls without error or slowdown', () => {
+        const originalNoColor = process.env.NO_COLOR;
+        delete process.env.NO_COLOR;
+
+        const texts = Array.from({ length: 5000 }, (_, i) => `output-${i}`);
+
+        const start = performance.now();
+        for (const text of texts) {
+            chalkToTermUI(mixedAnsi(text));
+        }
+        const elapsed = performance.now() - start;
+
+        // 5,000 mixed-ANSI calls should complete in under 500ms
+        expect(elapsed).toBeLessThan(500);
+    });
+
+    it('produces consistent output at 1,000-call scale', () => {
+        const originalNoColor = process.env.NO_COLOR;
+        delete process.env.NO_COLOR;
+
+        const results: string[] = [];
+        for (let i = 0; i < 1000; i++) {
+            results.push(chalkToTermUI(mixedAnsi(`item-${i}`)));
+        }
+
+        // Each result should contain the original text
+        expect(results[0]).toContain('item-0');
+        expect(results[999]).toContain('item-999');
+
+        // All results should have ANSI codes intact (no NO_COLOR)
+        for (const result of results) {
+            expect(result).toContain('\x1B[');
+        }
+    });
+
+    it('strips ANSI when NO_COLOR is set during high-volume calls', () => {
+        process.env.NO_COLOR = '1';
+
+        const texts = Array.from({ length: 1000 }, (_, i) => `line-${i}`);
+        const ansiTexts = texts.map((t, i) => {
+            const seq = MIXED_SEQUENCES[i % MIXED_SEQUENCES.length];
+            return buildAnsiString(seq, t);
+        });
+
+        const results: string[] = [];
+        for (const input of ansiTexts) {
+            results.push(chalkToTermUI(input));
+        }
+
+        // All results should be stripped of ANSI codes
+        for (const result of results) {
+            expect(result).not.toContain('\x1B[');
+            expect(result).toMatch(/^line-\d+$/);
+        }
+    });
+
+    it('handles deeply nested ANSI sequences', () => {
+        const originalNoColor = process.env.NO_COLOR;
+        delete process.env.NO_COLOR;
+
+        // Stack all sequences 10 times
+        let deeplyNested = 'text';
+        for (let i = 0; i < 10; i++) {
+            deeplyNested = mixedAnsi(deeplyNested);
+        }
+
+        // Should not throw and should preserve text content
+        const result = chalkToTermUI(deeplyNested);
+        expect(result).toBeDefined();
+        expect(result.length).toBeGreaterThan(0);
+    });
+
+    it('handles empty strings at high volume', () => {
+        const originalNoColor = process.env.NO_COLOR;
+        delete process.env.NO_COLOR;
+
+        expect(() => {
+            for (let i = 0; i < 1000; i++) {
+                chalkToTermUI('');
+            }
+        }).not.toThrow();
+    });
+});
diff --git a/packages/motion/src/easing-benchmark.test.ts b/packages/motion/src/easing-benchmark.test.ts
new file mode 100644
index 000000000..f48bb36d1
--- /dev/null
+++ b/packages/motion/src/easing-benchmark.test.ts
@@ -0,0 +1,84 @@
+// packages/motion/src/easing-benchmark.test.ts
+// Performance benchmarks for easing functions at simulated 60fps.
+
+import { describe, it, expect } from 'vitest';
+import { stepSpring, springPreset } from './spring.js';
+import { easings } from './transitions.js';
+
+const FRAME_DT_MS = 1000 / 60; // ~16.67ms per frame at 60fps
+const FRAME_DT_S = FRAME_DT_MS / 1000;
+const ITERATIONS = 10_000;
+
+/** Average time in milliseconds for a single easing tick */
+function benchmarkEasing(_name: string, fn: () => void): number {
+    const start = performance.now();
+    for (let i = 0; i < ITERATIONS; i++) {
+        fn();
+    }
+    const elapsed = performance.now() - start;
+    return elapsed / ITERATIONS;
+}
+
+describe('easing benchmark at 60fps', () => {
+    it('spring tick completes within 1ms per frame', () => {
+        const config = springPreset('default');
+        let state = { value: 0, velocity: 0, target: 1, done: false };
+        let totalMs = 0;
+
+        for (let i = 0; i < ITERATIONS; i++) {
+            const frameStart = performance.now();
+            state = stepSpring(state, config, FRAME_DT_S);
+            totalMs += performance.now() - frameStart;
+        }
+
+        const avgMs = totalMs / ITERATIONS;
+        expect(avgMs).toBeLessThan(1);
+    });
+
+    it('linear easing tick completes within 0.1ms per frame', () => {
+        let avgMs = benchmarkEasing('linear', () => {
+            easings.linear(0.5);
+        });
+        expect(avgMs).toBeLessThan(0.1);
+    });
+
+    it('easeInOut easing tick completes within 0.1ms per frame', () => {
+        let avgMs = benchmarkEasing('easeInOut', () => {
+            easings.easeInOut(0.5);
+        });
+        expect(avgMs).toBeLessThan(0.1);
+    });
+
+    it('spring reaches target within 60 frames at 60fps', () => {
+        const config = springPreset('default');
+        let state = { value: 0, velocity: 0, target: 1, done: false };
+        let frames = 0;
+        const maxFrames = 60; // 1 second at 60fps
+
+        while (!state.done && frames < maxFrames) {
+            state = stepSpring(state, config, FRAME_DT_S);
+            frames++;
+        }
+
+        expect(state.done).toBe(true);
+        expect(frames).toBeLessThanOrEqual(maxFrames);
+        expect(state.value).toBeCloseTo(1, 2);
+    });
+
+    it('linear interpolation is deterministic across frames', () => {
+        const progress: number[] = [];
+        for (let f = 0; f <= 10; f++) {
+            progress.push(easings.linear(f / 10));
+        }
+        expect(progress[5]).toBe(0.5);
+        expect(progress[10]).toBe(1);
+    });
+
+    it('easeInOut produces symmetric curve', () => {
+        const midpoint = easings.easeInOut(0.5);
+        expect(midpoint).toBeCloseTo(0.5);
+        // easeInOut(t) + easeInOut(1-t) should equal 1
+        expect(easings.easeInOut(0.25) + easings.easeInOut(0.75)).toBeCloseTo(1);
+        expect(easings.easeInOut(0.1) + easings.easeInOut(0.9)).toBeCloseTo(1);
+    });
+});