diff --git a/lib/cli/src/crewai_cli/create_crew.py b/lib/cli/src/crewai_cli/create_crew.py
index 549fc023e..334c398f2 100644
--- a/lib/cli/src/crewai_cli/create_crew.py
+++ b/lib/cli/src/crewai_cli/create_crew.py
@@ -14,6 +14,7 @@ from crewai_cli.provider import (
 )
 from crewai_cli.utils import (
     copy_template,
+    get_or_create_project_id,
     is_dmn_mode_enabled,
     load_env_vars,
     write_env_file,
@@ -320,6 +321,8 @@ def create_crew(
             copy_template(src_file, dst_file, name, class_name, folder_name)
 
     if not parent_folder:
+        # Minted at creation so the project has a stable identity from run one.
+        get_or_create_project_id(folder_path / "pyproject.toml")
         initialize_if_git_available(folder_path)
 
     click.secho(f"Crew {name} created successfully!", fg="green", bold=True)
diff --git a/lib/cli/src/crewai_cli/create_flow.py b/lib/cli/src/crewai_cli/create_flow.py
index 7921c2847..8345c95f4 100644
--- a/lib/cli/src/crewai_cli/create_flow.py
+++ b/lib/cli/src/crewai_cli/create_flow.py
@@ -5,6 +5,7 @@ import click
 from crewai_core.telemetry import Telemetry
 
 from crewai_cli.git import initialize_if_git_available
+from crewai_cli.utils import get_or_create_project_id
 from crewai_cli.version import get_crewai_tools_dependency
 
 
@@ -31,6 +32,8 @@ def create_flow(name: str, *, declarative: bool = False) -> None:
     else:
         _create_python_flow(name, class_name, folder_name, project_root)
 
+    # Minted at creation so the project has a stable identity from run one.
+    get_or_create_project_id(project_root / "pyproject.toml")
     initialize_if_git_available(project_root)
 
     click.secho(f"Flow {name} created successfully!", fg="green", bold=True)
diff --git a/lib/cli/src/crewai_cli/run_crew.py b/lib/cli/src/crewai_cli/run_crew.py
index c4116e1b6..55d357dae 100644
--- a/lib/cli/src/crewai_cli/run_crew.py
+++ b/lib/cli/src/crewai_cli/run_crew.py
@@ -20,6 +20,7 @@ from crewai_cli.input_prompt import (
 )
 from crewai_cli.utils import (
     build_env_with_all_tool_credentials,
+    ensure_project_id,
     is_dmn_mode_enabled,
 )
 from crewai_cli.version import get_crewai_tools_dependency, get_crewai_version
@@ -617,6 +618,10 @@ def run_crew(
             or declarative (JSON) crew. Layered over the definition's own
             defaults; missing required values are prompted for interactively.
     """
+    # Backfills projects created before project_id existed. Only here, in a
+    # command the user explicitly invoked - never from the SDK during kickoff.
+    ensure_project_id()
+
     # --definition is a pure override: run that flow directly.
     if definition is not None:
         _run_explicit_declarative_flow(
diff --git a/lib/cli/src/crewai_cli/tools/main.py b/lib/cli/src/crewai_cli/tools/main.py
index 9917f097a..4d3d54e57 100644
--- a/lib/cli/src/crewai_cli/tools/main.py
+++ b/lib/cli/src/crewai_cli/tools/main.py
@@ -16,6 +16,7 @@ from crewai_cli.config import Settings
 from crewai_cli.constants import DEFAULT_CREWAI_ENTERPRISE_URL
 from crewai_cli.utils import (
     build_env_with_tool_repository_credentials,
+    ensure_project_id,
     get_project_description,
     get_project_name,
     get_project_version,
@@ -229,7 +230,8 @@ class ToolCommand(BaseCommand, PlusAPIMixin):
     def login(self) -> None:
         get_user_id = _require_get_user_id()
         login_response = self.plus_api_client.login_to_tool_repository(
-            user_identifier=get_user_id()
+            user_identifier=get_user_id(),
+            project_id=ensure_project_id(),
         )
 
         if login_response.status_code != 200:
diff --git a/lib/cli/src/crewai_cli/utils.py b/lib/cli/src/crewai_cli/utils.py
index e20bcfea1..7fb26f80a 100644
--- a/lib/cli/src/crewai_cli/utils.py
+++ b/lib/cli/src/crewai_cli/utils.py
@@ -9,7 +9,9 @@ from typing import Any
 
 import click
 from crewai_core.project import (
+    get_or_create_project_id as get_or_create_project_id,
     get_project_description as get_project_description,
+    get_project_id as get_project_id,
     get_project_name as get_project_name,
     get_project_version as get_project_version,
     parse_toml as parse_toml,
@@ -29,8 +31,11 @@ __all__ = [
     "build_env_with_tool_repository_credentials",
     "copy_template",
     "enable_prompt_line_editing",
+    "ensure_project_id",
     "fetch_and_json_env_file",
+    "get_or_create_project_id",
     "get_project_description",
+    "get_project_id",
     "get_project_name",
     "get_project_version",
     "is_dmn_mode_enabled",
@@ -48,6 +53,32 @@ console = Console()
 _TEMPLATE_TOKEN_RE = re.compile(r"{{([a-zA-Z_][a-zA-Z0-9_]*)}}")
 
 
+def ensure_project_id(pyproject_path: str | Path = "pyproject.toml") -> str | None:
+    """Return the project's id, minting one and telling the user if it was added.
+
+    Safe to call from any CLI command: returns None rather than raising when
+    there is no project, or when ``pyproject.toml`` is not writable.
+
+    Args:
+        pyproject_path: Path to the project's ``pyproject.toml``.
+
+    Returns:
+        The project id, or None if one could not be read or created.
+    """
+    project_id, created = get_or_create_project_id(pyproject_path)
+
+    if created:
+        console.print(
+            f"Added [bold]project_id[/bold] to {pyproject_path} under "
+            # Escaped: Rich would otherwise parse [tool.crewai] as a style tag.
+            r"[bold]\[tool.crewai][/bold] so this project's runs and traces stay "
+            "linked. Commit it to share that link with your team.",
+            style="dim",
+        )
+
+    return project_id
+
+
 def is_dmn_mode_enabled() -> bool:
     """Return True when the enterprise non-interactive mode is enabled."""
     value = os.environ.get("CREWAI_DMN")
diff --git a/lib/crewai-core/src/crewai_core/plus_api.py b/lib/crewai-core/src/crewai_core/plus_api.py
index 4ed5e640d..c1acbad4e 100644
--- a/lib/crewai-core/src/crewai_core/plus_api.py
+++ b/lib/crewai-core/src/crewai_core/plus_api.py
@@ -69,7 +69,7 @@ class _WithUserIdentifier(TypedDict):
 
 
 class LoginPayload(_WithUserIdentifier):
-    pass
+    project_id: NotRequired[str]
 
 
 class TraceExecutionContext(TypedDict):
@@ -78,6 +78,7 @@ class TraceExecutionContext(TypedDict):
     flow_name: str | None
     crewai_version: str
     privacy_level: str
+    project_id: NotRequired[str | None]
 
 
 class TraceExecutionMetadata(TypedDict):
@@ -229,11 +230,24 @@ class PlusAPI:
             return client.request(method, url, files=files, **request_kwargs)
 
     def login_to_tool_repository(
-        self, user_identifier: str | None = None
+        self, user_identifier: str | None = None, project_id: str | None = None
     ) -> httpx.Response:
+        """Log in to the tool repository.
+
+        This request is authenticated, so sending user_identifier and project_id
+        alongside it links the account to the local pseudonymous user id and to
+        the project the command was run from - letting prior anonymous usage of
+        that project be attributed after signup.
+
+        Args:
+            user_identifier: Local pseudonymous user id.
+            project_id: ``[tool.crewai].project_id`` of the current project.
+        """
         payload: LoginPayload = {}
         if user_identifier:
             payload["user_identifier"] = user_identifier
+        if project_id:
+            payload["project_id"] = project_id
         return self._make_request("POST", f"{self.TOOLS_RESOURCE}/login", json=payload)
 
     def get_tool(self, handle: str) -> httpx.Response:
diff --git a/lib/crewai-core/src/crewai_core/project.py b/lib/crewai-core/src/crewai_core/project.py
index 9c7e6a33e..2ce1406bf 100644
--- a/lib/crewai-core/src/crewai_core/project.py
+++ b/lib/crewai-core/src/crewai_core/project.py
@@ -6,6 +6,7 @@ from functools import reduce
 from pathlib import Path, PureWindowsPath
 import sys
 from typing import Any
+import uuid
 
 from rich.console import Console
 import tomli
@@ -221,3 +222,121 @@ def get_project_description(
     return _get_project_attribute(
         pyproject_path, ["project", "description"], require=require
     )
+
+
+_PROJECT_ID_KEY = "project_id"
+
+
+def get_project_id(pyproject_path: str | Path = "pyproject.toml") -> str | None:
+    """Return ``[tool.crewai].project_id`` if the project has one.
+
+    Read-only and safe to call from library code: it never creates or modifies
+    anything. Use this everywhere except the CLI commands that are allowed to
+    mint an id (see :func:`get_or_create_project_id`).
+
+    Args:
+        pyproject_path: Path to the project's ``pyproject.toml``.
+
+    Returns:
+        The project id, or None when the file is missing, unreadable, or has
+        no id configured.
+    """
+    try:
+        pyproject_data = read_toml(pyproject_path)
+    except (OSError, tomli.TOMLDecodeError):
+        return None
+
+    project_id = get_crewai_project_config(pyproject_data).get(_PROJECT_ID_KEY)
+    return project_id if isinstance(project_id, str) and project_id else None
+
+
+def get_or_create_project_id(
+    pyproject_path: str | Path = "pyproject.toml",
+) -> tuple[str | None, bool]:
+    """Return the project's id, minting and persisting one if absent.
+
+    Writes ``project_id`` into the ``[tool.crewai]`` table so it is committed
+    with the repository. That makes it stable across machines, teammates, CI,
+    and containers - unlike a machine- or user-derived identifier.
+
+    Only CLI commands the user explicitly invoked should call this. Library
+    code must use :func:`get_project_id` instead; silently rewriting a user's
+    ``pyproject.toml`` during ``Crew.kickoff()`` would be surprising.
+
+    Args:
+        pyproject_path: Path to the project's ``pyproject.toml``.
+
+    Returns:
+        A ``(project_id, created)`` tuple. ``created`` is True only when an id
+        was minted and written on this call, so callers can tell the user. Both
+        values are ``(None, False)`` when the file is missing or not writable -
+        this is best-effort and never raises.
+    """
+    existing = get_project_id(pyproject_path)
+    if existing:
+        return existing, False
+
+    path = Path(pyproject_path)
+    if not path.is_file():
+        return None, False
+
+    try:
+        content = path.read_text(encoding="utf-8")
+    except OSError:
+        return None, False
+
+    project_id = str(uuid.uuid4())
+    updated = _insert_project_id(content, project_id)
+    if updated is None:
+        return None, False
+
+    try:
+        path.write_text(updated, encoding="utf-8")
+    except OSError:
+        # Read-only checkout, permissions, container FS - not worth failing over.
+        return None, False
+
+    return project_id, True
+
+
+def _insert_project_id(content: str, project_id: str) -> str | None:
+    """Add ``project_id`` to the ``[tool.crewai]`` table in TOML source text.
+
+    Edits the raw text rather than round-tripping through a TOML writer so
+    formatting, ordering, and comments in the rest of the file are preserved.
+
+    Args:
+        content: Full contents of a ``pyproject.toml``.
+        project_id: The id to insert.
+
+    Returns:
+        Updated file contents, or None if the edit could not be made safely.
+    """
+    lines = content.splitlines(keepends=True)
+    entry = f'{_PROJECT_ID_KEY} = "{project_id}"\n'
+
+    for index, line in enumerate(lines):
+        if line.strip() != "[tool.crewai]":
+            continue
+
+        # Insert at the end of the table, before the next table header, so the
+        # key cannot land inside a different section.
+        insert_at = len(lines)
+        for offset in range(index + 1, len(lines)):
+            if lines[offset].lstrip().startswith("["):
+                insert_at = offset
+                break
+
+        # Step back over trailing blank lines so the key stays in the table.
+        while insert_at > index + 1 and not lines[insert_at - 1].strip():
+            insert_at -= 1
+
+        if insert_at > 0 and not lines[insert_at - 1].endswith("\n"):
+            lines[insert_at - 1] += "\n"
+
+        lines.insert(insert_at, entry)
+        return "".join(lines)
+
+    # No [tool.crewai] table: append one rather than guessing where it belongs.
+    suffix = "" if content.endswith("\n") or not content else "\n"
+    return f"{content}{suffix}\n[tool.crewai]\n{entry}"
diff --git a/lib/crewai/src/crewai/events/listeners/tracing/trace_batch_manager.py b/lib/crewai/src/crewai/events/listeners/tracing/trace_batch_manager.py
index 72bb2452e..6f3abd399 100644
--- a/lib/crewai/src/crewai/events/listeners/tracing/trace_batch_manager.py
+++ b/lib/crewai/src/crewai/events/listeners/tracing/trace_batch_manager.py
@@ -14,6 +14,7 @@ from crewai_core.plus_api import (
     TraceExecutionMetadata,
     TraceFinalizePayload,
 )
+from crewai_core.project import get_project_id
 from crewai_core.settings import Settings
 from rich.console import Console
 from rich.panel import Panel
@@ -145,6 +146,10 @@ class TraceBatchManager:
                 "flow_name": execution_metadata.get("flow_name", None),
                 "crewai_version": self.current_batch.version,
                 "privacy_level": user_context.get("privacy_level", "standard"),
+                # Read-only: never mints an id. Sent on both the ephemeral and
+                # authenticated paths, so a project's traces stay attributable
+                # to it before and after the user creates an account.
+                "project_id": get_project_id(),
             }
             execution_metadata_payload: TraceExecutionMetadata = {
                 "expected_duration_estimate": execution_metadata.get(
diff --git a/lib/crewai/tests/telemetry/test_project_id.py b/lib/crewai/tests/telemetry/test_project_id.py
new file mode 100644
index 000000000..9b991796d
--- /dev/null
+++ b/lib/crewai/tests/telemetry/test_project_id.py
@@ -0,0 +1,177 @@
+"""Tests for the project_id used to link OSS usage to an enterprise account."""
+
+import uuid
+
+import pytest
+
+from crewai_core.project import (
+    get_or_create_project_id,
+    get_project_id,
+    parse_toml,
+)
+
+
+CREW_PYPROJECT = """\
+[project]
+name = "my_crew"
+version = "0.1.0"
+dependencies = ["crewai"]
+
+[tool.crewai]
+type = "crew"
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+"""
+
+
+@pytest.fixture
+def pyproject(tmp_path):
+    path = tmp_path / "pyproject.toml"
+    path.write_text(CREW_PYPROJECT)
+    return path
+
+
+def test_returns_none_when_no_id_configured(pyproject):
+    assert get_project_id(pyproject) is None
+
+
+def test_mints_and_persists_an_id(pyproject):
+    project_id, created = get_or_create_project_id(pyproject)
+
+    assert created is True
+    assert uuid.UUID(project_id)
+    assert get_project_id(pyproject) == project_id
+
+
+def test_id_is_stable_across_calls(pyproject):
+    first, created_first = get_or_create_project_id(pyproject)
+    second, created_second = get_or_create_project_id(pyproject)
+
+    assert created_first is True
+    assert created_second is False, "must not mint a second id"
+    assert first == second
+
+
+def test_id_lands_in_the_tool_crewai_table(pyproject):
+    project_id, _ = get_or_create_project_id(pyproject)
+
+    data = parse_toml(pyproject.read_text())
+    assert data["tool"]["crewai"]["project_id"] == project_id
+    assert data["tool"]["crewai"]["type"] == "crew", "existing keys must survive"
+
+
+def test_other_tables_are_preserved(pyproject):
+    get_or_create_project_id(pyproject)
+
+    data = parse_toml(pyproject.read_text())
+    assert data["project"]["name"] == "my_crew"
+    assert data["project"]["dependencies"] == ["crewai"]
+    assert data["build-system"]["build-backend"] == "hatchling.build"
+
+
+def test_comments_and_formatting_are_preserved(tmp_path):
+    """Raw-text editing rather than a TOML round-trip, so comments survive."""
+    path = tmp_path / "pyproject.toml"
+    path.write_text(
+        '# top comment\n[project]\nname = "x"  # inline comment\n\n[tool.crewai]\ntype = "flow"\n'
+    )
+
+    get_or_create_project_id(path)
+
+    content = path.read_text()
+    assert "# top comment" in content
+    assert "# inline comment" in content
+
+
+@pytest.mark.parametrize(
+    ("source", "label"),
+    [
+        ('[project]\nname = "x"\n\n[tool.crewai]\ntype = "crew"\n', "table then EOF"),
+        ('[tool.crewai]\ntype = "crew"', "no trailing newline"),
+        ('[project]\nname = "x"\n', "no tool.crewai table"),
+        ('[project]\nname = "x"\n[tool.crewai]\n[other]\na = 1\n', "empty table"),
+        (
+            '[tool.crewai]\ntype = "crew"\n\n\n[build-system]\nrequires = []\n',
+            "blank lines before next table",
+        ),
+    ],
+)
+def test_produces_valid_toml_for_varied_layouts(tmp_path, source, label):
+    path = tmp_path / "pyproject.toml"
+    path.write_text(source)
+
+    project_id, created = get_or_create_project_id(path)
+
+    assert created is True, label
+    data = parse_toml(path.read_text())
+    assert data["tool"]["crewai"]["project_id"] == project_id, label
+
+
+def test_id_does_not_leak_into_a_neighbouring_table(tmp_path):
+    """The key must never land under [build-system]."""
+    path = tmp_path / "pyproject.toml"
+    path.write_text(
+        '[tool.crewai]\ntype = "crew"\n\n[build-system]\nrequires = ["hatchling"]\n'
+    )
+
+    get_or_create_project_id(path)
+
+    data = parse_toml(path.read_text())
+    assert "project_id" in data["tool"]["crewai"]
+    assert "project_id" not in data["build-system"]
+
+
+def test_missing_file_is_not_an_error(tmp_path):
+    project_id, created = get_or_create_project_id(tmp_path / "nope.toml")
+
+    assert project_id is None
+    assert created is False
+
+
+def test_malformed_toml_is_not_an_error(tmp_path):
+    path = tmp_path / "pyproject.toml"
+    path.write_text("this is not [valid toml")
+
+    assert get_project_id(path) is None
+
+
+def test_read_only_file_is_not_an_error(pyproject):
+    """A read-only checkout must not break the command that called this."""
+    pyproject.chmod(0o444)
+    try:
+        project_id, created = get_or_create_project_id(pyproject)
+    finally:
+        pyproject.chmod(0o644)
+
+    assert project_id is None
+    assert created is False
+
+
+def test_get_project_id_never_creates_anything(pyproject):
+    """Library code calls the read-only variant; it must not mutate the file."""
+    before = pyproject.read_text()
+
+    assert get_project_id(pyproject) is None
+
+    assert pyproject.read_text() == before
+
+
+def test_blank_id_is_treated_as_absent(tmp_path):
+    path = tmp_path / "pyproject.toml"
+    path.write_text('[tool.crewai]\ntype = "crew"\nproject_id = ""\n')
+
+    assert get_project_id(path) is None
+
+
+def test_ids_are_unique_across_projects(tmp_path):
+    ids = set()
+    for name in ("a", "b", "c"):
+        path = tmp_path / name / "pyproject.toml"
+        path.parent.mkdir()
+        path.write_text(CREW_PYPROJECT)
+        project_id, _ = get_or_create_project_id(path)
+        ids.add(project_id)
+
+    assert len(ids) == 3