diff --git a/docs/designs/team-intelligence-platform.md b/docs/designs/team-intelligence-platform.md
index f7b7b04d1..cd7b366a0 100644
--- a/docs/designs/team-intelligence-platform.md
+++ b/docs/designs/team-intelligence-platform.md
@@ -74,9 +74,15 @@ Transform TeamAI from a simple skill-sharing CLI into a **Team Intelligence Plat
 **Data format (JSONL, one event per line):**
 ```jsonl
 {"skill":"code-review","timestamp":"2026-03-19T10:30:00Z","tool":"claude"}
-{"skill":"tdd","timestamp":"2026-03-19T10:35:00Z","tool":"claude"}
+{"skill":"tdd","timestamp":"2026-03-19T10:35:00Z","tool":"claude","cwd":"/home/dev/project-a"}
 ```
 
+`cwd` records the project the hook ran in and is absent on events written
+before it existed. Reports filter on it: a project-scope report keeps only
+events under its `projectRoot`, and the user-scope report excludes those, so one
+machine holding several projects never ships one project's usage to another
+team's stats.
+
 **Aggregation:** `teamai stats` 命令读取 JSONL 并聚合显示。
 
 **CLI output:**
diff --git a/src/__tests__/scope-filter.test.ts b/src/__tests__/scope-filter.test.ts
index 17794855b..656bb4d43 100644
--- a/src/__tests__/scope-filter.test.ts
+++ b/src/__tests__/scope-filter.test.ts
@@ -1,6 +1,6 @@
 import { describe, it, expect } from 'vitest';
 import { filterEventsByScope } from '../team-push.js';
-import type { DashboardEvent } from '../types.js';
+import type { DashboardEvent, UsageEvent } from '../types.js';
 
 function makeEvent(cwd: string | undefined, sessionId = 's1'): DashboardEvent {
   return { type: 'prompt_submit', timestamp: new Date().toISOString(), sessionId, tool: 'claude', cwd };
@@ -153,3 +153,44 @@ describe('filterEventsByScope', () => {
     });
   });
 });
+
+// Skill-usage events carry a cwd for the same reason dashboard events do: a
+// machine can hold several projects, and only the initialized one's usage may
+// reach the team repo (#748). Without it the filter drops every event.
+describe('filterEventsByScope with usage events (#748)', () => {
+  function makeUsage(cwd: string | undefined, skill = 'review'): UsageEvent {
+    return { skill, timestamp: new Date().toISOString(), tool: 'claude', cwd };
+  }
+
+  const usage: UsageEvent[] = [
+    makeUsage('/Users/jeff/project-a', 'a-skill'),
+    makeUsage('/Users/jeff/project-a/src', 'b-skill'),
+    makeUsage('/Users/jeff/other-work', 'c-skill'),
+    makeUsage('/Users/jeff/project-b', 'd-skill'),
+    makeUsage(undefined, 'e-skill'),
+  ];
+
+  it('filters usage to projectRoot', () => {
+    const result = filterEventsByScope(usage, { projectRoot: '/Users/jeff/project-a' });
+    expect(result.map((e) => e.skill)).toEqual(['a-skill', 'b-skill']);
+  });
+
+  it('excludeProjectRoots removes matching usage and keeps the rest', () => {
+    const result = filterEventsByScope(usage, { excludeProjectRoots: ['/Users/jeff/project-a'] });
+    expect(result.map((e) => e.skill)).toEqual(['c-skill', 'd-skill', 'e-skill']);
+  });
+
+  it('applies the same Windows rules as dashboard events', () => {
+    const winUsage: UsageEvent[] = [
+      makeUsage('C:\\Users\\jeff\\project-a', 'w1'),
+      makeUsage('C:\\Users\\jeff\\project-a\\src', 'w2'),
+      makeUsage('C:\\Users\\jeff\\other-work', 'w3'),
+    ];
+    expect(
+      filterEventsByScope(winUsage, { projectRoot: 'c:/users/JEFF/Project-A' }).map((e) => e.skill),
+    ).toEqual(['w1', 'w2']);
+    expect(
+      filterEventsByScope(winUsage, { excludeProjectRoots: ['C:\\Users\\jeff\\project-a'] }).map((e) => e.skill),
+    ).toEqual(['w3']);
+  });
+});
diff --git a/src/__tests__/team-push-interventions.test.ts b/src/__tests__/team-push-interventions.test.ts
index f46d1915a..fdadf744e 100644
--- a/src/__tests__/team-push-interventions.test.ts
+++ b/src/__tests__/team-push-interventions.test.ts
@@ -279,3 +279,49 @@ describe('reportUsageToTeam — preserve fields across partial reports (Issue #4
     expect(pushRepoDirectly).not.toHaveBeenCalled();
   });
 });
+
+describe('reportUsageToTeam — usage scope isolation (#748)', () => {
+  function seedMixedUsage(): string {
+    const usagePath = path.join(tmpDir, '.teamai', 'usage.jsonl');
+    fs.mkdirSync(path.dirname(usagePath), { recursive: true });
+    const base = { timestamp: new Date().toISOString(), tool: 'claude' };
+    // project-a is the reporting project; project-b never initialized teamai
+    // there, so its skill usage must not reach the team repo.
+    fs.writeFileSync(usagePath, [
+      { ...base, skill: 'team-review', cwd: '/p' },
+      { ...base, skill: 'team-lint', cwd: '/p/src' },
+      { ...base, skill: 'private-repo-skill', cwd: '/other-project' },
+      { ...base, skill: 'legacy-no-cwd' },
+    ].map((e) => JSON.stringify(e)).join('\n') + '\n');
+    return usagePath;
+  }
+
+  it('drops usage events from outside projectRoot', async () => {
+    seedMixedUsage();
+    expect(await reportUsageToTeam(repoDir, 'me', {
+      projectRoot: '/p',
+      selfConfig: { ...gitConfig(), scope: 'project', projectRoot: '/p' } as LocalConfig,
+    })).toBe(true);
+    const stats = YAML.parse(fs.readFileSync(reportsStatsPath(), 'utf-8'));
+    expect(Object.keys(stats.skills).sort()).toEqual(['team-lint', 'team-review']);
+    expect(stats.skills['private-repo-skill']).toBeUndefined();
+  });
+
+  it('excludes project sessions from the user-scope report', async () => {
+    seedMixedUsage();
+    expect(await reportUsageToTeam(repoDir, 'me', {
+      excludeProjectRoots: ['/p'],
+      selfConfig: gitConfig(),
+    })).toBe(true);
+    const stats = YAML.parse(fs.readFileSync(reportsStatsPath(), 'utf-8'));
+    expect(Object.keys(stats.skills).sort()).toEqual(['legacy-no-cwd', 'private-repo-skill']);
+    expect(stats.skills['team-review']).toBeUndefined();
+  });
+
+  it('keeps every event when no scope option is passed (backward compatible)', async () => {
+    seedMixedUsage();
+    expect(await reportUsageToTeam(repoDir, 'me', { selfConfig: gitConfig() })).toBe(true);
+    const stats = YAML.parse(fs.readFileSync(reportsStatsPath(), 'utf-8'));
+    expect(Object.keys(stats.skills).sort()).toEqual(['legacy-no-cwd', 'private-repo-skill', 'team-lint', 'team-review']);
+  });
+});
diff --git a/src/hook-handlers.ts b/src/hook-handlers.ts
index f28ee95cb..85940141b 100644
--- a/src/hook-handlers.ts
+++ b/src/hook-handlers.ts
@@ -200,6 +200,7 @@ const trackHandler: HookHandler = {
       skill: resolved.skillName,
       timestamp: new Date().toISOString(),
       tool: resolved.source ?? tool,
+      cwd: resolveHookCwd(stdin),
     });
     await updateKnownSkills(resolved.skillName);
     return null;
@@ -224,7 +225,7 @@ const trackSlashHandler: HookHandler = {
     const skillName = match[1];
     if (!isValidSkillName(skillName)) return null;
 
-    await appendUsageEvent({ skill: skillName, timestamp: new Date().toISOString(), tool });
+    await appendUsageEvent({ skill: skillName, timestamp: new Date().toISOString(), tool, cwd: resolveHookCwd(stdin) });
     await updateKnownSkills(skillName);
     return null;
   },
diff --git a/src/team-push.ts b/src/team-push.ts
index c7f371ef1..a6d516fba 100644
--- a/src/team-push.ts
+++ b/src/team-push.ts
@@ -352,15 +352,27 @@ function isUnderScopeRoot(cwd: string, root: ScopeRoot): boolean {
 }
 
 /**
- * Filter dashboard events by scope:
+ * Any local event that records the working directory it came from.
+ *
+ * Dashboard events and skill-usage events both carry an optional `cwd`; the
+ * scope rules below only ever read that one field, so they apply to both.
+ */
+type ScopedEvent = { cwd?: string };
+
+/**
+ * Filter scope-carrying events by scope:
  * - projectRoot set: keep only events whose cwd is under that root.
  * - excludeProjectRoots set: exclude events whose cwd is under any listed root.
  * - Neither: return all events (backward-compatible).
+ *
+ * The semantics are deliberately shared by dashboard events and skill-usage
+ * events: both are written by hooks that run in whatever directory the AI tool
+ * was started in, and a machine can hold several projects at once (#748).
  */
-export function filterEventsByScope(
-  events: DashboardEvent[],
+export function filterEventsByScope<T extends ScopedEvent>(
+  events: T[],
   opts?: { projectRoot?: string; excludeProjectRoots?: string[] },
-): DashboardEvent[] {
+): T[] {
   if (!opts) return events;
   if (opts.projectRoot) {
     const root = scopeRoot(opts.projectRoot);
@@ -403,7 +415,10 @@ export async function reportUsageToTeam(
   // only for callers that did not pass a config.
 
   try {
-    const events = await readUsageEvents();
+    // Skill usage is scoped exactly like dashboard events: hooks write a cwd for
+    // both, and a machine can hold several projects, so an unfiltered report
+    // would ship one project's usage to another team's stats (#748).
+    const events = filterEventsByScope(await readUsageEvents(), options);
     const filesToPush: string[] = [];
 
     // Fold the local dashboard event log into per-session metrics once, then derive
diff --git a/src/types.ts b/src/types.ts
index 126f340c6..b390986e6 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1051,12 +1051,25 @@ export interface UsageEvent {
   skill: string;
   timestamp: string;
   tool: string;
+  /**
+   * Working directory the skill was used in, as reported by the AI tool's hook
+   * payload. Optional because events written before this field existed have no
+   * value, and because a hook may legitimately run without one.
+   *
+   * Reports filter on it so a machine holding several projects only ships the
+   * initialized project's usage (#748). A `projectRoot` report therefore drops
+   * an event with no cwd — it cannot be shown to belong to that project — while
+   * `excludeProjectRoots` keeps it, since it cannot be shown to belong to an
+   * excluded one either.
+   */
+  cwd?: string;
 }
 
 export const UsageEventSchema = z.object({
   skill: z.string().regex(SKILL_NAME_REGEX),
   timestamp: z.string(),
   tool: z.string(),
+  cwd: z.string().optional(),
 });
 
 // ─── Stats YAML (team repo: stats/<user>.yaml) ─────────
diff --git a/src/usage-tracker.ts b/src/usage-tracker.ts
index bbed0b350..4e7457d6f 100644
--- a/src/usage-tracker.ts
+++ b/src/usage-tracker.ts
@@ -9,6 +9,7 @@ import {
 } from './types.js';
 import { ensureDir, readJson, writeJson, pathExists } from './utils/fs.js';
 import { getUserHome } from './utils/home.js';
+import { resolveHookCwd } from './utils/hook-cwd.js';
 
 /** Get the usage JSONL path (evaluated at call time to respect HOME changes in tests). */
 function getUsagePath(): string {
@@ -426,6 +427,7 @@ export async function trackFromStdin(toolArg?: string): Promise<void> {
     skill: skillName,
     timestamp: new Date().toISOString(),
     tool: toolSource,
+    cwd: resolveHookCwd(hookData),
   };
 
   await appendUsageEvent(event);
@@ -451,7 +453,7 @@ export async function trackSlashCommand(toolArg?: string): Promise<void> {
     return;
   }
 
-  let hookData: { prompt?: string };
+  let hookData: { prompt?: string; cwd?: unknown; workspace_roots?: unknown };
   try {
     hookData = JSON.parse(raw);
   } catch {
@@ -491,6 +493,7 @@ export async function trackSlashCommand(toolArg?: string): Promise<void> {
       skill: skillName,
       timestamp: new Date().toISOString(),
       tool: toolArg ?? 'claude',
+      cwd: resolveHookCwd(hookData),
     };
 
     await appendUsageEvent(event);