feat: add Bitbucket Pipelines OIDC detector

Add Bitbucket Pipelines to OIDC credential auto-discovery. When a pipeline
step sets `oidc: true`, the CLI reads the OIDC token from the
BITBUCKET_STEP_OIDC_TOKEN environment variable and exchanges it for a
Cloudsmith access token. Works out of the box with no extra dependencies.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: cloudsmith-iduffy

CHANGELOG.md

@@ -8,6 +8,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+### Added
+
+- Added Bitbucket Pipelines to OIDC credential auto-discovery. When a pipeline step sets `oidc: true`, the CLI reads the OIDC token from the `BITBUCKET_STEP_OIDC_TOKEN` environment variable and exchanges it for a Cloudsmith access token. Works out of the box with no extra dependencies.
+
 ## [1.17.0] - 2026-05-18
 
 ### Added

README.md

@@ -165,6 +165,21 @@ pip install cloudsmith-cli[all]
 
 **Note:** If you don't install the AWS extra, the AWS OIDC detector will gracefully skip itself with no errors.
 
+#### Bitbucket Pipelines OIDC Support
+
+In Bitbucket Pipelines, OIDC credential discovery works out of the box with no extra dependencies. Set `oidc: true` on the pipeline step and the CLI reads the token from the `BITBUCKET_STEP_OIDC_TOKEN` variable that Bitbucket populates. The Cloudsmith OIDC provider must expect the workspace audience that Bitbucket mints (`ari:cloud:bitbucket::workspace/<workspace-uuid>`):
+
+```yaml
+pipelines:
+  default:
+    - step:
+        oidc: true
+        script:
+          - cloudsmith push ...
+```
+
+See the [Bitbucket Pipelines OIDC documentation](https://support.atlassian.com/bitbucket-cloud/docs/integrate-pipelines-with-resource-servers-using-oidc/).
+
 ## Configuration
 
 There are two configuration files used by the CLI:

cloudsmith_cli/core/credentials/oidc/detectors/__init__.py

@@ -7,13 +7,15 @@
 
 from .aws import AWSDetector
 from .base import EnvironmentDetector
+from .bitbucket_pipelines import BitbucketPipelinesDetector
 
 if TYPE_CHECKING:
     from ... import CredentialContext
 
 logger = logging.getLogger(__name__)
 
 _DETECTORS: list[type[EnvironmentDetector]] = [
+    BitbucketPipelinesDetector,
     AWSDetector,
 ]
 

cloudsmith_cli/core/credentials/oidc/detectors/bitbucket_pipelines.py

@@ -0,0 +1,34 @@
+# Copyright 2026 Cloudsmith Ltd
+"""Bitbucket Pipelines OIDC detector.
+
+Reads an OIDC token from the ``BITBUCKET_STEP_OIDC_TOKEN`` environment variable,
+which Bitbucket populates when ``oidc: true`` is set on a pipeline step.
+
+References:
+    https://support.atlassian.com/bitbucket-cloud/docs/integrate-pipelines-with-resource-servers-using-oidc/
+    https://support.atlassian.com/bitbucket-cloud/docs/variables-and-secrets/
+"""
+
+from __future__ import annotations
+
+import os
+
+from .base import EnvironmentDetector
+
+
+class BitbucketPipelinesDetector(EnvironmentDetector):
+    """Detects Bitbucket Pipelines and reads its OIDC token from environment."""
+
+    name = "Bitbucket Pipelines"
+
+    def detect(self) -> bool:
+        return bool(os.environ.get("BITBUCKET_STEP_OIDC_TOKEN"))
+
+    def get_token(self) -> str:
+        token = os.environ.get("BITBUCKET_STEP_OIDC_TOKEN")
+        if not token:
+            raise ValueError(
+                "BITBUCKET_STEP_OIDC_TOKEN is not set. Enable OIDC on the "
+                "pipeline step with 'oidc: true'."
+            )
+        return token

cloudsmith_cli/core/tests/test_bitbucket_pipelines_detector.py

@@ -0,0 +1,55 @@
+"""Tests for the Bitbucket Pipelines OIDC detector."""
+
+from unittest import mock
+
+import pytest
+
+from cloudsmith_cli.core.credentials.models import CredentialContext
+from cloudsmith_cli.core.credentials.oidc.detectors import detect_environment
+from cloudsmith_cli.core.credentials.oidc.detectors.bitbucket_pipelines import (
+    BitbucketPipelinesDetector,
+)
+
+
+@pytest.fixture
+def bitbucket_env():
+    env = {
+        "BITBUCKET_STEP_OIDC_TOKEN": "the-jwt",
+    }
+    with mock.patch.dict("os.environ", env, clear=True):
+        yield env
+
+
+class TestDetect:
+    def test_detects_when_token_present(self, bitbucket_env):
+        detector = BitbucketPipelinesDetector(context=CredentialContext())
+        assert detector.detect() is True
+
+    def test_not_detected_when_unset(self):
+        with mock.patch.dict("os.environ", {}, clear=True):
+            detector = BitbucketPipelinesDetector(context=CredentialContext())
+            assert detector.detect() is False
+
+    def test_not_detected_when_token_empty(self, bitbucket_env):
+        bitbucket_env["BITBUCKET_STEP_OIDC_TOKEN"] = ""
+        with mock.patch.dict("os.environ", bitbucket_env, clear=True):
+            detector = BitbucketPipelinesDetector(context=CredentialContext())
+            assert detector.detect() is False
+
+
+class TestGetToken:
+    def test_returns_token(self, bitbucket_env):
+        detector = BitbucketPipelinesDetector(context=CredentialContext())
+        assert detector.get_token() == "the-jwt"
+
+    def test_raises_when_token_missing(self):
+        with mock.patch.dict("os.environ", {}, clear=True):
+            detector = BitbucketPipelinesDetector(context=CredentialContext())
+            with pytest.raises(ValueError):
+                detector.get_token()
+
+
+class TestIntegration:
+    def test_detect_environment_selects_bitbucket_pipelines(self, bitbucket_env):
+        detector = detect_environment(CredentialContext())
+        assert isinstance(detector, BitbucketPipelinesDetector)