diff --git a/README.md b/README.md
index dbb11bd..9e4fbd9 100644
--- a/README.md
+++ b/README.md
@@ -1192,7 +1192,8 @@ abs events list --from 7d --to now
 abs events list --event-name my-experiment --event-type exposure --from 5h
 abs events list --app 1 --unit-type 2 --event-type exposure --items 50
 abs events list --unit-uid user123 --env-type production
-abs events list --effective-exposures --from 1d              # only assignment-changing exposures
+abs events list --valid-exposures --from 1d                  # only assignment-changing exposures
+abs events list --invalid-exposures --from 1d                # only ineffective exposures (filtered out)
 abs events list --event-name exp1 --event-name exp2          # multiple names (all filters repeatable)
 abs events history --from 7d --period 1d
 abs events history --event-name my-experiment --env-type production
diff --git a/package.json b/package.json
index 3ea1c3c..9e769b7 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@absmartly/cli",
-  "version": "1.5.0",
+  "version": "1.6.0",
   "description": "ABSmartly CLI - A/B Testing and Feature Flags command-line tool for AI agents and humans",
   "type": "module",
   "main": "./dist/index.js",
diff --git a/src/commands/events/events.test.ts b/src/commands/events/events.test.ts
index da17fd1..f0d41c3 100644
--- a/src/commands/events/events.test.ts
+++ b/src/commands/events/events.test.ts
@@ -96,6 +96,30 @@ describe('events command', () => {
     expect(printFormatted).toHaveBeenCalled();
   });
 
+  it('should send effective_exposures=true with --valid-exposures', async () => {
+    await eventsCommand.parseAsync(['node', 'test', 'list', '--valid-exposures']);
+    expect(mockClient.listEvents).toHaveBeenCalledWith({
+      filters: { effective_exposures: true },
+    });
+  });
+
+  it('should send effective_exposures=false with --invalid-exposures', async () => {
+    await eventsCommand.parseAsync(['node', 'test', 'list', '--invalid-exposures']);
+    expect(mockClient.listEvents).toHaveBeenCalledWith({
+      filters: { effective_exposures: false },
+    });
+  });
+
+  it('should reject combining --valid-exposures and --invalid-exposures', async () => {
+    await expect(
+      eventsCommand.parseAsync(['node', 'test', 'list', '--valid-exposures', '--invalid-exposures'])
+    ).rejects.toThrow('process.exit');
+    expect(consoleErrorSpy).toHaveBeenCalledWith(
+      expect.anything(),
+      expect.stringContaining('mutually exclusive')
+    );
+  });
+
   it('should list events history with filters', async () => {
     await eventsCommand.parseAsync([
       'node',
diff --git a/src/commands/events/index.ts b/src/commands/events/index.ts
index 28bc25a..e939972 100644
--- a/src/commands/events/index.ts
+++ b/src/commands/events/index.ts
@@ -51,7 +51,8 @@ const listCommand = new Command('list')
     parseStringArray,
     []
   )
-  .option('--effective-exposures', 'only effective exposures')
+  .option('--valid-exposures', 'only valid (effective) exposures')
+  .option('--invalid-exposures', 'only invalid (ineffective) exposures')
   .option('--items <count>', 'number of items to take', Number)
   .option('--skip <count>', 'number of items to skip', Number)
   .action(
@@ -59,6 +60,15 @@ const listCommand = new Command('list')
       const globalOptions = getGlobalOptions(listCommand);
       const client = await getAPIClientFromOptions(globalOptions);
 
+      if (options.validExposures && options.invalidExposures) {
+        throw new Error('--valid-exposures and --invalid-exposures are mutually exclusive');
+      }
+      const validExposures = options.validExposures
+        ? true
+        : options.invalidExposures
+          ? false
+          : undefined;
+
       const fromTs = parseDateFlagOrUndefined(options.from);
       const toTs = parseDateFlagOrUndefined(options.to);
 
@@ -71,7 +81,7 @@ const listCommand = new Command('list')
         eventNames: options.eventName.length > 0 ? options.eventName : undefined,
         unitUids: options.unitUid.length > 0 ? options.unitUid : undefined,
         environmentTypes: options.envType.length > 0 ? options.envType : undefined,
-        effectiveExposures: options.effectiveExposures || undefined,
+        validExposures,
         take: options.items,
         skip: options.skip,
       });
diff --git a/src/commands/experiments/list.ts b/src/commands/experiments/list.ts
index d7e5022..4ea811e 100644
--- a/src/commands/experiments/list.ts
+++ b/src/commands/experiments/list.ts
@@ -3,11 +3,11 @@ import {
   getAPIClientFromOptions,
   getGlobalOptions,
   printFormatted,
+  shouldOutputIdsOnly,
   withErrorHandling,
 } from '../../lib/utils/api-helper.js';
 import { printPaginationFooter } from '../../lib/utils/pagination.js';
 import { getDefaultType } from './default-type.js';
-import { isStdoutPiped } from '../../lib/utils/stdin.js';
 import { listExperiments } from '../../core/experiments/list.js';
 
 export const listCommand = new Command('list')
@@ -73,7 +73,7 @@ export const listCommand = new Command('list')
         raw: globalOptions.raw,
       });
 
-      if (globalOptions.output === 'ids' || (isStdoutPiped() && !options.output)) {
+      if (shouldOutputIdsOnly(globalOptions)) {
         for (const exp of result.data) console.log((exp as Record<string, unknown>).id);
         return;
       }
diff --git a/src/core/events/events.test.ts b/src/core/events/events.test.ts
index dea538c..d6499f9 100644
--- a/src/core/events/events.test.ts
+++ b/src/core/events/events.test.ts
@@ -109,6 +109,28 @@ describe('events', () => {
       await listEvents(mockClient as any, {});
       expect(mockClient.listEvents).toHaveBeenCalledWith({});
     });
+
+    it('should send effective_exposures=true when validExposures is true', async () => {
+      mockClient.listEvents.mockResolvedValue([]);
+      await listEvents(mockClient as any, { validExposures: true });
+      expect(mockClient.listEvents).toHaveBeenCalledWith({
+        filters: { effective_exposures: true },
+      });
+    });
+
+    it('should send effective_exposures=false when validExposures is false', async () => {
+      mockClient.listEvents.mockResolvedValue([]);
+      await listEvents(mockClient as any, { validExposures: false });
+      expect(mockClient.listEvents).toHaveBeenCalledWith({
+        filters: { effective_exposures: false },
+      });
+    });
+
+    it('should omit effective_exposures when validExposures is undefined', async () => {
+      mockClient.listEvents.mockResolvedValue([]);
+      await listEvents(mockClient as any, { from: 1 });
+      expect(mockClient.listEvents).toHaveBeenCalledWith({ filters: { from: 1 } });
+    });
   });
 
   describe('listEventsHistory', () => {
diff --git a/src/core/events/events.ts b/src/core/events/events.ts
index 248f9b0..8ef1b35 100644
--- a/src/core/events/events.ts
+++ b/src/core/events/events.ts
@@ -44,7 +44,7 @@ export interface ListEventsParams {
   eventNames?: string[] | undefined;
   unitUids?: string[] | undefined;
   environmentTypes?: string[] | undefined;
-  effectiveExposures?: boolean | undefined;
+  validExposures?: boolean | undefined;
   take?: number | undefined;
   skip?: number | undefined;
 }
@@ -64,7 +64,7 @@ export async function listEvents(
   if (params.unitUids && params.unitUids.length > 0) filters.unit_uids = params.unitUids;
   if (params.environmentTypes && params.environmentTypes.length > 0)
     filters.environment_types = params.environmentTypes;
-  if (params.effectiveExposures) filters.effective_exposures = true;
+  if (params.validExposures !== undefined) filters.effective_exposures = params.validExposures;
 
   const body: Record<string, unknown> = {};
   if (Object.keys(filters).length > 0) body.filters = filters;
diff --git a/src/lib/utils/api-helper.test.ts b/src/lib/utils/api-helper.test.ts
index b458983..d38aeeb 100644
--- a/src/lib/utils/api-helper.test.ts
+++ b/src/lib/utils/api-helper.test.ts
@@ -23,6 +23,7 @@ import {
   getAPIClientFromOptions,
   getGlobalOptions,
   printFormatted,
+  shouldOutputIdsOnly,
   withErrorHandling,
   resolveAuth,
 } from './api-helper.js';
@@ -30,6 +31,7 @@ import { loadConfig, getProfile } from '../config/config.js';
 import { getAPIKey, getOAuthToken } from '../config/keyring.js';
 import { createAPIClient } from '../api/client.js';
 import { formatOutput } from '../output/formatter.js';
+import { setTTYOverride } from './stdin.js';
 
 describe('API Helper', () => {
   const savedEnv: Record<string, string | undefined> = {};
@@ -307,6 +309,86 @@ describe('API Helper', () => {
         })
       );
     });
+
+    describe('outputExplicit', () => {
+      it('is false when --output is not passed on the CLI', () => {
+        // Mock command at line 192 registers --output with a default of 'table'.
+        // Defaults must NOT count as "explicit" — that's the whole point.
+        mockCommand.parse(['node', 'test']);
+
+        const options = getGlobalOptions(mockCommand);
+        expect(options.output).toBe('table');
+        expect(options.outputExplicit).toBe(false);
+      });
+
+      it('is true when --output is passed on the CLI', () => {
+        mockCommand.parse(['node', 'test', '--output', 'json']);
+
+        const options = getGlobalOptions(mockCommand);
+        expect(options.output).toBe('json');
+        expect(options.outputExplicit).toBe(true);
+      });
+
+      it('is true even when the user explicitly chooses table', () => {
+        // Regression: prior implementation could not distinguish "no flag"
+        // from "explicit -o table", which broke piping into table format.
+        mockCommand.parse(['node', 'test', '--output', 'table']);
+
+        const options = getGlobalOptions(mockCommand);
+        expect(options.output).toBe('table');
+        expect(options.outputExplicit).toBe(true);
+      });
+
+      it('is detected on the leaf subcommand when --output is set as a global option', () => {
+        const root = new Command();
+        root.option('-o, --output <format>', 'output format');
+        const sub = new Command('list');
+        root.addCommand(sub);
+
+        root.parse(['node', 'test', '--output', 'json', 'list']);
+
+        const options = getGlobalOptions(sub);
+        expect(options.output).toBe('json');
+        expect(options.outputExplicit).toBe(true);
+      });
+    });
+  });
+
+  describe('shouldOutputIdsOnly', () => {
+    afterEach(() => {
+      setTTYOverride({ stdin: true, stdout: true });
+    });
+
+    it('returns true when output is explicitly "ids"', () => {
+      setTTYOverride({ stdout: true });
+      expect(shouldOutputIdsOnly({ output: 'ids', outputExplicit: true })).toBe(true);
+    });
+
+    it('returns true when stdout is piped and no explicit --output was given', () => {
+      setTTYOverride({ stdout: false });
+      expect(shouldOutputIdsOnly({ output: 'table', outputExplicit: false })).toBe(true);
+    });
+
+    it('returns false when stdout is piped but the user explicitly chose --output json', () => {
+      // Regression: this is the original bug — piped + -o json was forcing ids.
+      setTTYOverride({ stdout: false });
+      expect(shouldOutputIdsOnly({ output: 'json', outputExplicit: true })).toBe(false);
+    });
+
+    it('returns false when stdout is piped but the user explicitly chose --output table', () => {
+      setTTYOverride({ stdout: false });
+      expect(shouldOutputIdsOnly({ output: 'table', outputExplicit: true })).toBe(false);
+    });
+
+    it('returns false on a TTY when no explicit output was given', () => {
+      setTTYOverride({ stdout: true });
+      expect(shouldOutputIdsOnly({ output: 'table', outputExplicit: false })).toBe(false);
+    });
+
+    it('returns false on a TTY when explicit --output json was given', () => {
+      setTTYOverride({ stdout: true });
+      expect(shouldOutputIdsOnly({ output: 'json', outputExplicit: true })).toBe(false);
+    });
   });
 
   describe('withErrorHandling', () => {
diff --git a/src/lib/utils/api-helper.ts b/src/lib/utils/api-helper.ts
index 9e09fe8..e5514be 100644
--- a/src/lib/utils/api-helper.ts
+++ b/src/lib/utils/api-helper.ts
@@ -4,6 +4,7 @@ import { getAPIKey, getOAuthToken } from '../config/keyring.js';
 import type { AuthConfig } from '../api/axios-adapter.js';
 import { Command } from 'commander';
 import { formatOutput, type OutputFormat } from '../output/formatter.js';
+import { isStdoutPiped } from './stdin.js';
 
 export async function resolveAPIKey(options: GlobalOptions): Promise<string> {
   const config = loadConfig();
@@ -101,6 +102,10 @@ export interface GlobalOptions {
   app?: string;
   env?: string;
   output?: OutputFormat;
+  // True when the user explicitly set --output (via CLI or env), false when
+  // the value was defaulted. Used to decide whether to auto-switch to ids
+  // mode when stdout is piped.
+  outputExplicit?: boolean;
   noColor?: boolean;
   // True when the user explicitly disabled color (--no-color or NO_COLOR env).
   // noColor above additionally disables when stdout isn't a TTY; this field
@@ -135,6 +140,8 @@ const VALID_FORMATS: OutputFormat[] = [
 export function getGlobalOptions(cmd: Command): GlobalOptions {
   const opts = cmd.optsWithGlobals();
   const output = (opts.output || 'table') as OutputFormat;
+  const outputSource = cmd.getOptionValueSourceWithGlobals('output');
+  const outputExplicit = outputSource === 'cli' || outputSource === 'env';
 
   if (!VALID_FORMATS.includes(output)) {
     throw new Error(
@@ -155,6 +162,7 @@ export function getGlobalOptions(cmd: Command): GlobalOptions {
     app: opts.app,
     env: opts.env,
     output,
+    outputExplicit,
     noColor: colorDisabled || !process.stdout.isTTY,
     colorDisabled,
     verbose: opts.verbose || false,
@@ -172,6 +180,13 @@ export function getGlobalOptions(cmd: Command): GlobalOptions {
   };
 }
 
+// When stdout is piped to another process, list commands fall back to
+// emitting ids only — unless the user explicitly chose an output format.
+// Centralizes the rule so every list-style command behaves the same way.
+export function shouldOutputIdsOnly(globalOptions: GlobalOptions): boolean {
+  return globalOptions.output === 'ids' || (isStdoutPiped() && !globalOptions.outputExplicit);
+}
+
 export function printFormatted(data: unknown, globalOptions: GlobalOptions): void {
   const output = formatOutput(data, globalOptions.output, {
     noColor: globalOptions.noColor ?? false,
diff --git a/src/lib/utils/list-command.test.ts b/src/lib/utils/list-command.test.ts
index 6541ede..7526e16 100644
--- a/src/lib/utils/list-command.test.ts
+++ b/src/lib/utils/list-command.test.ts
@@ -2,6 +2,7 @@ import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 import { createListCommand } from './list-command.js';
 import { getAPIClientFromOptions, getGlobalOptions, printFormatted } from './api-helper.js';
 import { resetCommand } from '../../test/helpers/command-reset.js';
+import { setTTYOverride } from './stdin.js';
 
 vi.mock('./api-helper.js', async (importOriginal) => {
   const actual = await importOriginal<typeof import('./api-helper.js')>();
@@ -68,4 +69,66 @@ describe('createListCommand', () => {
     expect(mockFetch).toHaveBeenCalledWith(mockClient, expect.any(Object));
     expect(printFormatted).toHaveBeenCalled();
   });
+
+  describe('output behavior under piping', () => {
+    afterEach(() => {
+      setTTYOverride({ stdin: true, stdout: true });
+    });
+
+    it('prints only ids when stdout is piped and no explicit output is set', async () => {
+      setTTYOverride({ stdout: false });
+      vi.mocked(getGlobalOptions).mockReturnValue({
+        output: 'table',
+        outputExplicit: false,
+      } as any);
+      const fetch = vi.fn().mockResolvedValue([{ id: 1 }, { id: 2 }, { id: 3 }]);
+      const cmd = createListCommand({ description: 'List items', fetch });
+      resetCommand(cmd);
+
+      await cmd.parseAsync(['node', 'test']);
+
+      expect(printFormatted).not.toHaveBeenCalled();
+      expect(consoleSpy).toHaveBeenCalledWith(1);
+      expect(consoleSpy).toHaveBeenCalledWith(2);
+      expect(consoleSpy).toHaveBeenCalledWith(3);
+    });
+
+    it('renders the requested format when stdout is piped and -o json is explicit', async () => {
+      // Regression: previously `--items 200 -o json` over a pipe collapsed
+      // to id-only output because the command read its local `options.output`
+      // (always undefined — the flag lives on the root program), so the
+      // "is explicit?" check always said no.
+      setTTYOverride({ stdout: false });
+      vi.mocked(getGlobalOptions).mockReturnValue({
+        output: 'json',
+        outputExplicit: true,
+      } as any);
+      const fetch = vi.fn().mockResolvedValue([{ id: 1 }, { id: 2 }]);
+      const cmd = createListCommand({ description: 'List items', fetch });
+      resetCommand(cmd);
+
+      await cmd.parseAsync(['node', 'test']);
+
+      expect(printFormatted).toHaveBeenCalledOnce();
+      // Items must not have been spilled as bare ids on stdout.
+      expect(consoleSpy).not.toHaveBeenCalledWith(1);
+      expect(consoleSpy).not.toHaveBeenCalledWith(2);
+    });
+
+    it('prints only ids when output is explicitly "ids", even on a TTY', async () => {
+      setTTYOverride({ stdout: true });
+      vi.mocked(getGlobalOptions).mockReturnValue({
+        output: 'ids',
+        outputExplicit: true,
+      } as any);
+      const fetch = vi.fn().mockResolvedValue([{ id: 42 }]);
+      const cmd = createListCommand({ description: 'List items', fetch });
+      resetCommand(cmd);
+
+      await cmd.parseAsync(['node', 'test']);
+
+      expect(printFormatted).not.toHaveBeenCalled();
+      expect(consoleSpy).toHaveBeenCalledWith(42);
+    });
+  });
 });
diff --git a/src/lib/utils/list-command.ts b/src/lib/utils/list-command.ts
index 4bfa452..ba72c6f 100644
--- a/src/lib/utils/list-command.ts
+++ b/src/lib/utils/list-command.ts
@@ -3,9 +3,9 @@ import {
   getAPIClientFromOptions,
   getGlobalOptions,
   printFormatted,
+  shouldOutputIdsOnly,
   withErrorHandling,
 } from './api-helper.js';
-import { isStdoutPiped } from './stdin.js';
 import { addPaginationOptions, printPaginationFooter } from './pagination.js';
 import { applyShowExclude } from '../../api-client/entity-summary.js';
 import type { APIClient } from '../../api-client/api-client.js';
@@ -42,7 +42,7 @@ export function createListCommand(opts: ListCommandOptions): Command {
 
       const items = await opts.fetch(client, options);
 
-      if (globalOptions.output === 'ids' || (isStdoutPiped() && !options.output)) {
+      if (shouldOutputIdsOnly(globalOptions)) {
         for (const item of items) console.log((item as Record<string, unknown>).id);
         return;
       }
diff --git a/vitest.config.ts b/vitest.config.ts
index 6e89984..6cc345b 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -1,6 +1,6 @@
 import { config } from 'dotenv';
 config({ path: ['.env.test.local', '.env.local', '.env'] });
-import { defineConfig } from 'vitest/config';
+import { configDefaults, defineConfig } from 'vitest/config';
 
 const isLiveMode = process.env.USE_LIVE_API === '1';
 
@@ -12,6 +12,9 @@ export default defineConfig({
     hookTimeout: isLiveMode ? 15_000 : 10_000,
     setupFiles: ['./src/test/setup.ts'],
     fileParallelism: false,
+    // Sibling git worktrees live under .worktrees/ and would otherwise be
+    // discovered as duplicate test files against stale source.
+    exclude: [...configDefaults.exclude, '.worktrees/**'],
     server: {
       deps: {
         inline: ['absmartly-api-mocks'],