braintrustdata · Abhijeet Prasad (AbhiPrasad) · Aug 19, 2026 · Aug 19, 2026
diff --git a/py/src/braintrust/api/cassettes/test_projects_end_to_end_with_real_backend.yaml b/py/src/braintrust/api/cassettes/test_projects_end_to_end_with_real_backend.yaml
diff --git a/py/src/braintrust/api/test_projects.py b/py/src/braintrust/api/test_projects.py
@@ -1,5 +1,7 @@
 import pytest
+from braintrust import init_logger
 from braintrust.api import BraintrustClient
+from braintrust.logger import BraintrustState
 
 
 @pytest.mark.vcr
@@ -22,6 +24,14 @@ def test_projects_end_to_end_with_real_backend(api_key):
         updated = client.openapi.projects.patch_project_id(
             created["id"], body={"description": "updated by the Python SDK VCR test"}
         )
+
+        state = BraintrustState()
+        state.login(api_key=api_key, org_name=discovery.organization.name)
+        registered_logger = init_logger(project=project_name, state=state, set_current=False)
+        looked_up_logger = init_logger(project_id=created["id"], state=state, set_current=False)
+        assert registered_logger.id == created["id"]
+        assert looked_up_logger.project.name == project_name
+
         deleted = client.openapi.projects.delete_project_id(created["id"])
 
     assert create_project == {

diff --git a/py/src/braintrust/cassettes/test_register_sandbox_single_evaluator.yaml b/py/src/braintrust/cassettes/test_register_sandbox_single_evaluator.yaml
@@ -1,76 +1,4 @@
 interactions:
-- request:
-    body: '{"project_name": "My Project", "org_id": "bf61839e-94bb-4a81-85ed-26b533a24b61"}'
-    headers:
-      Accept:
-      - '*/*'
-      Accept-Encoding:
-      - gzip, deflate
-      Connection:
-      - keep-alive
-      Content-Length:
-      - '80'
-      Content-Type:
-      - application/json
-      User-Agent:
-      - python-requests/2.32.5
-    method: POST
-    uri: https://www.braintrust.dev/api/project/register
-  response:
-    body:
-      string: '{"project":{"id":"6b770640-a26a-4680-9d69-537262023137","org_id":"bf61839e-94bb-4a81-85ed-26b533a24b61","name":"My
-        Project","description":null,"created":"2026-03-12T19:49:37.394Z","deleted_at":null,"user_id":"fd67d1e5-c011-43fa-8096-ee5fed2b7df1","settings":null},"found_existing":true}'
-    headers:
-      Cache-Control:
-      - public, max-age=0, must-revalidate
-      Content-Length:
-      - '286'
-      Content-Security-Policy:
-      - 'script-src ''self'' ''unsafe-eval'' ''wasm-unsafe-eval'' ''strict-dynamic''
-        ''nonce-ZDFkNjJkY2EtMWVmOS00ZTZmLThjZTItNGRmMjAzMWZlZDZh''  *.js.stripe.com
-        js.stripe.com maps.googleapis.com ; style-src ''self'' ''unsafe-inline'' *.braintrust.dev
-        btcm6qilbbhv4yi1.public.blob.vercel-storage.com fonts.googleapis.com www.gstatic.com
-        d4tuoctqmanu0.cloudfront.net; font-src ''self'' data: fonts.gstatic.com btcm6qilbbhv4yi1.public.blob.vercel-storage.com
-        cdn.jsdelivr.net d4tuoctqmanu0.cloudfront.net fonts.googleapis.com mintlify-assets.b-cdn.net
-        fonts.cdnfonts.com; object-src ''none''; base-uri ''self''; form-action ''self'';
-        frame-ancestors ''self''; worker-src ''self'' blob:; report-uri https://o4507221741076480.ingest.us.sentry.io/api/4507221754380288/security/?sentry_key=27fa5ac907cf7c6ce4a1ab2a03f805b4&sentry_environment=production&sentry_release=16;
-        report-to csp-endpoint-0'
-      Content-Type:
-      - application/json; charset=utf-8
-      Date:
-      - Thu, 12 Mar 2026 20:26:58 GMT
-      Etag:
-      - '"kzpvhxucks7y"'
-      Reporting-Endpoints:
-      - csp-endpoint-0="https://o4507221741076480.ingest.us.sentry.io/api/4507221754380288/security/?sentry_key=27fa5ac907cf7c6ce4a1ab2a03f805b4&sentry_environment=production&sentry_release=16"
-      Server:
-      - Vercel
-      Strict-Transport-Security:
-      - max-age=63072000
-      X-Bt-Was-Udf-Cached:
-      - 'true'
-      X-Clerk-Auth-Message:
-      - Invalid JWT form. A JWT consists of three parts separated by dots. (reason=token-invalid,
-        token-carrier=header)
-      X-Clerk-Auth-Reason:
-      - token-invalid
-      X-Clerk-Auth-Status:
-      - signed-out
-      X-Content-Type-Options:
-      - nosniff
-      X-Frame-Options:
-      - SAMEORIGIN
-      X-Matched-Path:
-      - /api/project/register
-      X-Nonce:
-      - ZDFkNjJkY2EtMWVmOS00ZTZmLThjZTItNGRmMjAzMWZlZDZh
-      X-Vercel-Cache:
-      - MISS
-      X-Vercel-Id:
-      - sfo1::iad1::tp2pw-1773347218334-903d13f4bb17
-    status:
-      code: 200
-      message: OK
 - request:
     body: '{"sandbox_spec": {"provider": "modal", "snapshot_ref": "im-icRxmsk1Sz9XPP2f8OblVU"},
       "entrypoints": ["./local/js/optimization/evals/btql-generation/btql-queries.eval.ts"],

diff --git a/py/src/braintrust/cassettes/test_register_sandbox_with_entrypoints.yaml b/py/src/braintrust/cassettes/test_register_sandbox_with_entrypoints.yaml
@@ -1,76 +1,4 @@
 interactions:
-- request:
-    body: '{"project_name": "My Project", "org_id": "bf61839e-94bb-4a81-85ed-26b533a24b61"}'
-    headers:
-      Accept:
-      - '*/*'
-      Accept-Encoding:
-      - gzip, deflate
-      Connection:
-      - keep-alive
-      Content-Length:
-      - '80'
-      Content-Type:
-      - application/json
-      User-Agent:
-      - python-requests/2.32.5
-    method: POST
-    uri: https://www.braintrust.dev/api/project/register
-  response:
-    body:
-      string: '{"project":{"id":"6b770640-a26a-4680-9d69-537262023137","org_id":"bf61839e-94bb-4a81-85ed-26b533a24b61","name":"My
-        Project","description":null,"created":"2026-03-12T19:49:37.394Z","deleted_at":null,"user_id":"fd67d1e5-c011-43fa-8096-ee5fed2b7df1","settings":null},"found_existing":true}'
-    headers:
-      Cache-Control:
-      - public, max-age=0, must-revalidate
-      Content-Length:
-      - '286'
-      Content-Security-Policy:
-      - 'script-src ''self'' ''unsafe-eval'' ''wasm-unsafe-eval'' ''strict-dynamic''
-        ''nonce-ZDFkNjJkY2EtMWVmOS00ZTZmLThjZTItNGRmMjAzMWZlZDZh''  *.js.stripe.com
-        js.stripe.com maps.googleapis.com ; style-src ''self'' ''unsafe-inline'' *.braintrust.dev
-        btcm6qilbbhv4yi1.public.blob.vercel-storage.com fonts.googleapis.com www.gstatic.com
-        d4tuoctqmanu0.cloudfront.net; font-src ''self'' data: fonts.gstatic.com btcm6qilbbhv4yi1.public.blob.vercel-storage.com
-        cdn.jsdelivr.net d4tuoctqmanu0.cloudfront.net fonts.googleapis.com mintlify-assets.b-cdn.net
-        fonts.cdnfonts.com; object-src ''none''; base-uri ''self''; form-action ''self'';
-        frame-ancestors ''self''; worker-src ''self'' blob:; report-uri https://o4507221741076480.ingest.us.sentry.io/api/4507221754380288/security/?sentry_key=27fa5ac907cf7c6ce4a1ab2a03f805b4&sentry_environment=production&sentry_release=16;
-        report-to csp-endpoint-0'
-      Content-Type:
-      - application/json; charset=utf-8
-      Date:
-      - Thu, 12 Mar 2026 20:26:58 GMT
-      Etag:
-      - '"kzpvhxucks7y"'
-      Reporting-Endpoints:
-      - csp-endpoint-0="https://o4507221741076480.ingest.us.sentry.io/api/4507221754380288/security/?sentry_key=27fa5ac907cf7c6ce4a1ab2a03f805b4&sentry_environment=production&sentry_release=16"
-      Server:
-      - Vercel
-      Strict-Transport-Security:
-      - max-age=63072000
-      X-Bt-Was-Udf-Cached:
-      - 'true'
-      X-Clerk-Auth-Message:
-      - Invalid JWT form. A JWT consists of three parts separated by dots. (reason=token-invalid,
-        token-carrier=header)
-      X-Clerk-Auth-Reason:
-      - token-invalid
-      X-Clerk-Auth-Status:
-      - signed-out
-      X-Content-Type-Options:
-      - nosniff
-      X-Frame-Options:
-      - SAMEORIGIN
-      X-Matched-Path:
-      - /api/project/register
-      X-Nonce:
-      - ZDFkNjJkY2EtMWVmOS00ZTZmLThjZTItNGRmMjAzMWZlZDZh
-      X-Vercel-Cache:
-      - MISS
-      X-Vercel-Id:
-      - sfo1::iad1::tp2pw-1773347218334-903d13f4bb17
-    status:
-      code: 200
-      message: OK
 - request:
     body: '{"sandbox_spec": {"provider": "modal", "snapshot_ref": "im-icRxmsk1Sz9XPP2f8OblVU"},
       "entrypoints": ["./local/js/optimization/evals/btql-generation/btql-queries.eval.ts"],

diff --git a/py/src/braintrust/cassettes/test_register_sandbox_with_metadata_and_description.yaml b/py/src/braintrust/cassettes/test_register_sandbox_with_metadata_and_description.yaml
@@ -1,76 +1,4 @@
 interactions:
-- request:
-    body: '{"project_name": "My Project", "org_id": "bf61839e-94bb-4a81-85ed-26b533a24b61"}'
-    headers:
-      Accept:
-      - '*/*'
-      Accept-Encoding:
-      - gzip, deflate
-      Connection:
-      - keep-alive
-      Content-Length:
-      - '80'
-      Content-Type:
-      - application/json
-      User-Agent:
-      - python-requests/2.32.5
-    method: POST
-    uri: https://www.braintrust.dev/api/project/register
-  response:
-    body:
-      string: '{"project":{"id":"6b770640-a26a-4680-9d69-537262023137","org_id":"bf61839e-94bb-4a81-85ed-26b533a24b61","name":"My
-        Project","description":null,"created":"2026-03-12T19:49:37.394Z","deleted_at":null,"user_id":"fd67d1e5-c011-43fa-8096-ee5fed2b7df1","settings":null},"found_existing":true}'
-    headers:
-      Cache-Control:
-      - public, max-age=0, must-revalidate
-      Content-Length:
-      - '286'
-      Content-Security-Policy:
-      - 'script-src ''self'' ''unsafe-eval'' ''wasm-unsafe-eval'' ''strict-dynamic''
-        ''nonce-OTZlNWI3NDUtOWJjYi00NjA3LWI3MzEtNzhhZWQ0OGNmMmFh''  *.js.stripe.com
-        js.stripe.com maps.googleapis.com ; style-src ''self'' ''unsafe-inline'' *.braintrust.dev
-        btcm6qilbbhv4yi1.public.blob.vercel-storage.com fonts.googleapis.com www.gstatic.com
-        d4tuoctqmanu0.cloudfront.net; font-src ''self'' data: fonts.gstatic.com btcm6qilbbhv4yi1.public.blob.vercel-storage.com
-        cdn.jsdelivr.net d4tuoctqmanu0.cloudfront.net fonts.googleapis.com mintlify-assets.b-cdn.net
-        fonts.cdnfonts.com; object-src ''none''; base-uri ''self''; form-action ''self'';
-        frame-ancestors ''self''; worker-src ''self'' blob:; report-uri https://o4507221741076480.ingest.us.sentry.io/api/4507221754380288/security/?sentry_key=27fa5ac907cf7c6ce4a1ab2a03f805b4&sentry_environment=production&sentry_release=16;
-        report-to csp-endpoint-0'
-      Content-Type:
-      - application/json; charset=utf-8
-      Date:
-      - Thu, 12 Mar 2026 20:26:48 GMT
-      Etag:
-      - '"kzpvhxucks7y"'
-      Reporting-Endpoints:
-      - csp-endpoint-0="https://o4507221741076480.ingest.us.sentry.io/api/4507221754380288/security/?sentry_key=27fa5ac907cf7c6ce4a1ab2a03f805b4&sentry_environment=production&sentry_release=16"
-      Server:
-      - Vercel
-      Strict-Transport-Security:
-      - max-age=63072000
-      X-Bt-Was-Udf-Cached:
-      - 'true'
-      X-Clerk-Auth-Message:
-      - Invalid JWT form. A JWT consists of three parts separated by dots. (reason=token-invalid,
-        token-carrier=header)
-      X-Clerk-Auth-Reason:
-      - token-invalid
-      X-Clerk-Auth-Status:
-      - signed-out
-      X-Content-Type-Options:
-      - nosniff
-      X-Frame-Options:
-      - SAMEORIGIN
-      X-Matched-Path:
-      - /api/project/register
-      X-Nonce:
-      - OTZlNWI3NDUtOWJjYi00NjA3LWI3MzEtNzhhZWQ0OGNmMmFh
-      X-Vercel-Cache:
-      - MISS
-      X-Vercel-Id:
-      - sfo1::iad1::8hdkr-1773347208825-87a220df8e21
-    status:
-      code: 200
-      message: OK
 - request:
     body: '{"sandbox_spec": {"provider": "modal", "snapshot_ref": "im-icRxmsk1Sz9XPP2f8OblVU"},
       "entrypoints": ["./local/js/optimization/evals/btql-generation/btql-queries.eval.ts"],

diff --git a/py/src/braintrust/framework2.py b/py/src/braintrust/framework2.py
@@ -4,7 +4,7 @@
 from typing import Any, overload
 
 import slugify
-from braintrust.logger import api_conn, app_conn, login
+from braintrust.logger import _internal_get_global_state, api_conn, login
 
 from .framework import _is_lazy_load, bcolors  # type: ignore
 from .generated_types import (
@@ -28,8 +28,9 @@ def __init__(self):
 
     def get_by_name(self, project_name: str) -> str:
         if project_name not in self._name_cache:
-            resp = app_conn().post_json("api/project/register", {"project_name": project_name})
-            self._name_cache[project_name] = resp["project"]["id"]
+            state = _internal_get_global_state()
+            project = state.api_client().projects.post_project(body={"name": project_name, "org_name": state.org_name})
+            self._name_cache[project_name] = project["id"]
         return self._name_cache[project_name]
 
     def get(self, project: "Project") -> str:

diff --git a/py/src/braintrust/logger.py b/py/src/braintrust/logger.py
@@ -1737,26 +1737,27 @@ def compute_metadata():
     )
 
 
-def _compute_logger_metadata(project_name: str | None = None, project_id: str | None = None):
-    login()
-    org_id = _state.org_id
+def _compute_logger_metadata(
+    project_name: str | None = None,
+    project_id: str | None = None,
+    state: BraintrustState | None = None,
+):
+    state = state or _state
+    state.login()
+    org_id = state.org_id
     if project_id is None:
-        response = _state.app_conn().post_json(
-            "api/project/register",
-            {
-                "project_name": project_name or GLOBAL_PROJECT,
-                "org_id": org_id,
-            },
+        response = state.api_client().projects.post_project(
+            body={"name": project_name or GLOBAL_PROJECT, "org_name": state.org_name}
         )
-        resp_project = response["project"]
         return OrgProjectMetadata(
             org_id=org_id,
-            project=ObjectMetadata(id=resp_project["id"], name=resp_project["name"], full_info=resp_project),
+            project=ObjectMetadata(id=response["id"], name=response["name"], full_info=dict(response)),
         )
     elif project_name is None:
-        response = _state.app_conn().get_json("api/project", {"id": project_id})
+        response = state.api_client().projects.get_project_id(project_id)
         return OrgProjectMetadata(
-            org_id=org_id, project=ObjectMetadata(id=project_id, name=response["name"], full_info=response)
+            org_id=org_id,
+            project=ObjectMetadata(id=response["id"], name=response["name"], full_info=dict(response)),
         )
     else:
         return OrgProjectMetadata(
@@ -1804,7 +1805,7 @@ def init_logger(
 
     def compute_metadata():
         state.login(org_name=org_name, api_key=api_key, app_url=app_url, force_login=force_login)
-        return _compute_logger_metadata(**compute_metadata_args)
+        return _compute_logger_metadata(**compute_metadata_args, state=state)
 
     # For loggers, enable queue size limit enforcement (bounded queue)
     state.enforce_queue_size_limit(True)
@@ -5515,17 +5516,13 @@ def lazy_init(self):
         if self._id is None or self._name is None:
             with self.init_lock:
                 if self._id is None:
-                    response = _state.app_conn().post_json(
-                        "api/project/register",
-                        {
-                            "project_name": self._name or GLOBAL_PROJECT,
-                            "org_id": _state.org_id,
-                        },
+                    response = _state.api_client().projects.post_project(
+                        body={"name": self._name or GLOBAL_PROJECT, "org_name": _state.org_name}
                     )
-                    self._id = response["project"]["id"]
-                    self._name = response["project"]["name"]
+                    self._id = response["id"]
+                    self._name = response["name"]
                 elif self._name is None:
-                    response = _state.app_conn().get_json("api/project", {"id": self._id})
+                    response = _state.api_client().projects.get_project_id(self._id)
                     self._name = response["name"]
 
         return self

diff --git a/py/src/braintrust/sandbox.py b/py/src/braintrust/sandbox.py
@@ -91,10 +91,8 @@ def register_sandbox(
     state = state or _state
     state.login(api_key=api_key, app_url=app_url, org_name=org_name)
 
-    project_response = state.app_conn().post_json(
-        "api/project/register", {"project_name": project, "org_id": state.org_id}
-    )
-    project_id = project_response["project"]["id"]
+    project_response = state.api_client().projects.post_project(body={"name": project, "org_name": state.org_name})
+    project_id = project_response["id"]
 
     runtime_context = {
         "runtime": "python",

diff --git a/py/src/braintrust/test_framework2.py b/py/src/braintrust/test_framework2.py
@@ -1,7 +1,7 @@
 """Tests for framework2 module, specifically metadata and tags support."""
 
 import importlib.util
-from unittest.mock import MagicMock
+from unittest.mock import MagicMock, patch
 
 import pytest
 
@@ -13,6 +13,23 @@
 HAS_PYDANTIC = importlib.util.find_spec("pydantic") is not None
 
 
+def test_project_id_cache_uses_generated_project_registration():
+    mock_state = MagicMock()
+    mock_state.org_name = "test-org"
+    mock_state.api_client.return_value.projects.post_project.return_value = {
+        "id": "generated-project-id",
+        "name": "test-project",
+    }
+    with patch("braintrust.logger._state", mock_state):
+        project_id = ProjectIdCache().get_by_name("test-project")
+
+    assert project_id == "generated-project-id"
+    mock_state.api_client.return_value.projects.post_project.assert_called_once_with(
+        body={"name": "test-project", "org_name": "test-org"}
+    )
+    mock_state.app_conn.assert_not_called()
+
+
 class TestCodeFunctionMetadata:
     """Tests for CodeFunction metadata support."""