diff --git a/src/sentry/api/urls.py b/src/sentry/api/urls.py
index 4f7292c1b2b8b6..87654dca0763c7 100644
--- a/src/sentry/api/urls.py
+++ b/src/sentry/api/urls.py
@@ -542,6 +542,9 @@
     OrganizationSeerAgentUpdateEndpoint,
 )
 from sentry.seer.endpoints.organization_seer_onboarding_check import OrganizationSeerOnboardingCheck
+from sentry.seer.endpoints.organization_seer_project_repos import (
+    OrganizationSeerProjectRepoDetailsEndpoint,
+)
 from sentry.seer.endpoints.organization_seer_rpc import OrganizationSeerRpcEndpoint
 from sentry.seer.endpoints.organization_seer_setup_check import OrganizationSeerSetupCheckEndpoint
 from sentry.seer.endpoints.organization_seer_workflows import OrganizationSeerWorkflowsEndpoint
@@ -2449,6 +2452,11 @@ def create_group_urls(name_prefix: str) -> list[URLPattern | URLResolver]:
         OrganizationSeerOnboardingCheck.as_view(),
         name="sentry-api-0-organization-seer-onboarding-check",
     ),
+    re_path(
+        r"^(?P<organization_id_or_slug>[^/]+)/seer/projects/(?P<project_id>\d+)/repos/(?P<repo_id>\d+)/$",
+        OrganizationSeerProjectRepoDetailsEndpoint.as_view(),
+        name="sentry-api-0-organization-seer-project-repo-details",
+    ),
     re_path(
         r"^(?P<organization_id_or_slug>[^/]+)/autofix/automation-settings/$",
         OrganizationAutofixAutomationSettingsEndpoint.as_view(),
diff --git a/src/sentry/seer/endpoints/organization_seer_project_repos.py b/src/sentry/seer/endpoints/organization_seer_project_repos.py
new file mode 100644
index 00000000000000..59a0a159b53f8e
--- /dev/null
+++ b/src/sentry/seer/endpoints/organization_seer_project_repos.py
@@ -0,0 +1,190 @@
+from __future__ import annotations
+
+from typing import TypedDict
+
+from django.db import router, transaction
+from rest_framework import serializers
+from rest_framework.request import Request
+from rest_framework.response import Response
+
+from sentry.api.api_owners import ApiOwner
+from sentry.api.api_publish_status import ApiPublishStatus
+from sentry.api.base import cell_silo_endpoint
+from sentry.api.bases.organization import OrganizationEndpoint, OrganizationPermission
+from sentry.api.serializers.rest_framework import CamelSnakeSerializer
+from sentry.constants import ObjectStatus
+from sentry.models.organization import Organization
+from sentry.models.project import Project
+from sentry.seer.autofix.utils import replace_all_branch_overrides
+from sentry.seer.models.project_repository import SeerProjectRepository
+from sentry.seer.seer_setup import get_supported_scm_providers
+
+
+class BranchOverrideResponse(TypedDict):
+    id: str
+    tagName: str
+    tagValue: str
+    branchName: str
+
+
+class ProjectRepoResponse(TypedDict):
+    id: str
+    repositoryId: str
+    organizationId: str
+    provider: str
+    owner: str
+    name: str
+    externalId: str
+    integrationId: str | None
+    branchName: str | None
+    branchOverrides: list[BranchOverrideResponse]
+    instructions: str | None
+
+
+def _serialize_project_repo(project_repo: SeerProjectRepository) -> ProjectRepoResponse:
+    repo = project_repo.project_repository.repository
+    name_parts = repo.name.split("/", 1)
+    owner = name_parts[0] if len(name_parts) > 1 else ""
+    name = name_parts[1] if len(name_parts) > 1 else repo.name
+
+    return ProjectRepoResponse(
+        id=str(project_repo.id),
+        repositoryId=str(repo.id),
+        organizationId=str(repo.organization_id),
+        provider=repo.provider or "",
+        owner=owner,
+        name=name,
+        externalId=repo.external_id or "",
+        integrationId=str(repo.integration_id) if repo.integration_id is not None else None,
+        branchName=project_repo.branch_name,
+        branchOverrides=[
+            BranchOverrideResponse(
+                id=str(bo.id),
+                tagName=bo.tag_name,
+                tagValue=bo.tag_value,
+                branchName=bo.branch_name,
+            )
+            for bo in project_repo.branch_overrides.all()
+        ],
+        instructions=project_repo.instructions,
+    )
+
+
+def _valid_project_repos_queryset(project: Project, organization: Organization):
+    """Get a project's base SeerProjectRepository queryset for active repos with providers supported by Seer."""
+    return SeerProjectRepository.objects.filter(
+        project_repository__project=project,
+        project_repository__repository__status=ObjectStatus.ACTIVE,
+        project_repository__repository__provider__in=get_supported_scm_providers(organization),
+    ).select_related("project_repository", "project_repository__repository")
+
+
+def _validate_branch_overrides(value):
+    if not value:
+        return value
+    seen: set[tuple[str, str]] = set()
+    for override in value:
+        key = (override["tag_name"], override["tag_value"])
+        if key in seen:
+            raise serializers.ValidationError(
+                f"Duplicate branch override for tag {key[0]}={key[1]}"
+            )
+        seen.add(key)
+    return value
+
+
+class BranchOverrideSerializer(CamelSnakeSerializer):
+    tag_name = serializers.CharField(required=True)
+    tag_value = serializers.CharField(required=True)
+    branch_name = serializers.CharField(required=True)
+
+
+class SeerProjectRepoUpdateSerializer(CamelSnakeSerializer):
+    branch_name = serializers.CharField(required=False, allow_null=True, allow_blank=True)
+    instructions = serializers.CharField(required=False, allow_null=True, allow_blank=True)
+    branch_overrides = BranchOverrideSerializer(many=True, required=False, allow_null=False)
+
+    def validate_branch_overrides(self, value):
+        return _validate_branch_overrides(value)
+
+    def validate(self, data):
+        if not data:
+            raise serializers.ValidationError("At least one field must be provided.")
+        return data
+
+
+@cell_silo_endpoint
+class OrganizationSeerProjectRepoDetailsEndpoint(OrganizationEndpoint):
+    owner = ApiOwner.ML_AI
+    publish_status = {
+        "GET": ApiPublishStatus.EXPERIMENTAL,
+        "PUT": ApiPublishStatus.EXPERIMENTAL,
+        "DELETE": ApiPublishStatus.EXPERIMENTAL,
+    }
+    permission_classes = (OrganizationPermission,)
+
+    def get(
+        self, request: Request, organization: Organization, project_id: int, repo_id: int
+    ) -> Response:
+        project = self.get_projects(request, organization, project_ids={int(project_id)})[0]
+
+        project_repo = (
+            _valid_project_repos_queryset(project, organization)
+            .prefetch_related("branch_overrides")
+            .filter(project_repository__repository_id=repo_id)
+            .first()
+        )
+        if project_repo is None:
+            return Response(status=404)
+
+        return Response(_serialize_project_repo(project_repo))
+
+    def put(
+        self, request: Request, organization: Organization, project_id: int, repo_id: int
+    ) -> Response:
+        project = self.get_projects(request, organization, project_ids={int(project_id)})[0]
+
+        serializer = SeerProjectRepoUpdateSerializer(data=request.data)
+        if not serializer.is_valid():
+            return Response(serializer.errors, status=400)
+
+        data = serializer.validated_data
+
+        with transaction.atomic(router.db_for_write(SeerProjectRepository)):
+            project_repo = (
+                _valid_project_repos_queryset(project, organization)
+                .select_for_update()
+                .filter(project_repository__repository_id=repo_id)
+                .first()
+            )
+            if project_repo is None:
+                return Response(status=404)
+
+            if "branch_name" in data:
+                project_repo.branch_name = data["branch_name"]
+            if "instructions" in data:
+                project_repo.instructions = data["instructions"]
+            if "branch_name" in data or "instructions" in data:
+                project_repo.save()
+
+            if "branch_overrides" in data:
+                replace_all_branch_overrides(project_repo, data["branch_overrides"])
+
+        return Response(_serialize_project_repo(project_repo))
+
+    def delete(
+        self, request: Request, organization: Organization, project_id: int, repo_id: int
+    ) -> Response:
+        project = self.get_projects(request, organization, project_ids={int(project_id)})[0]
+
+        with transaction.atomic(router.db_for_write(SeerProjectRepository)):
+            deleted_count, _ = (
+                _valid_project_repos_queryset(project, organization)
+                .filter(project_repository__repository_id=repo_id)
+                .delete()
+            )
+
+        if deleted_count == 0:
+            return Response(status=404)
+
+        return Response(status=204)
diff --git a/static/app/utils/api/knownSentryApiUrls.generated.ts b/static/app/utils/api/knownSentryApiUrls.generated.ts
index 61408ae7391e9d..30c79e447db31c 100644
--- a/static/app/utils/api/knownSentryApiUrls.generated.ts
+++ b/static/app/utils/api/knownSentryApiUrls.generated.ts
@@ -559,6 +559,7 @@ export type KnownSentryApiUrls =
   | '/organizations/$organizationIdOrSlug/seer/explorer-update/$runId/'
   | '/organizations/$organizationIdOrSlug/seer/onboarding-check/'
   | '/organizations/$organizationIdOrSlug/seer/projects/'
+  | '/organizations/$organizationIdOrSlug/seer/projects/$projectId/repos/$repoId/'
   | '/organizations/$organizationIdOrSlug/seer/setup-check/'
   | '/organizations/$organizationIdOrSlug/seer/supergroups/$supergroupId/'
   | '/organizations/$organizationIdOrSlug/seer/supergroups/by-group/'
diff --git a/tests/sentry/seer/endpoints/test_organization_seer_project_repos.py b/tests/sentry/seer/endpoints/test_organization_seer_project_repos.py
new file mode 100644
index 00000000000000..1140efee32db2e
--- /dev/null
+++ b/tests/sentry/seer/endpoints/test_organization_seer_project_repos.py
@@ -0,0 +1,298 @@
+from django.urls import reverse
+
+from sentry.constants import ObjectStatus
+from sentry.seer.models.project_repository import (
+    SeerProjectRepository,
+    SeerProjectRepositoryBranchOverride,
+)
+from sentry.testutils.cases import APITestCase
+
+
+class OrganizationSeerProjectRepoDetailsGetTest(APITestCase):
+    endpoint = "sentry-api-0-organization-seer-project-repo-details"
+
+    def detail_url(self, repo_id):
+        return reverse(
+            self.endpoint,
+            kwargs={
+                "organization_id_or_slug": self.organization.slug,
+                "project_id": self.project.id,
+                "repo_id": repo_id,
+            },
+        )
+
+    def reverse_url(self):
+        return self.detail_url(self.repo1.id)
+
+    def setUp(self) -> None:
+        super().setUp()
+        self.login_as(user=self.user)
+        self.repo1 = self.create_repo(
+            project=self.project,
+            name="getsentry/sentry",
+            provider="integrations:github",
+            external_id="111",
+        )
+
+    def test_get_repo(self):
+        project_repo = self.create_seer_project_repository(
+            self.project, repository=self.repo1, branch_name="main", instructions="hello"
+        )
+        SeerProjectRepositoryBranchOverride.objects.create(
+            seer_project_repository=project_repo,
+            tag_name="environment",
+            tag_value="production",
+            branch_name="release",
+        )
+
+        response = self.get_success_response()
+        assert response.data["repositoryId"] == str(self.repo1.id)
+        assert response.data["branchName"] == "main"
+        assert response.data["instructions"] == "hello"
+        assert len(response.data["branchOverrides"]) == 1
+        assert response.data["branchOverrides"][0]["tagName"] == "environment"
+        assert response.data["branchOverrides"][0]["tagValue"] == "production"
+        assert response.data["branchOverrides"][0]["branchName"] == "release"
+
+    def test_not_connected_repo_returns_404(self):
+        self.get_error_response(status_code=404)
+
+    def test_inactive_repo_returns_404(self):
+        self.create_seer_project_repository(self.project, repository=self.repo1)
+        self.repo1.status = ObjectStatus.HIDDEN
+        self.repo1.save()
+
+        self.get_error_response(status_code=404)
+
+    def test_nonexistent_repo_returns_404(self):
+        response = self.client.get(self.detail_url(99999))
+        assert response.status_code == 404
+
+    def test_unsupported_provider_returns_404(self):
+        self.create_seer_project_repository(self.project, repository=self.repo1)
+        self.repo1.provider = "integrations:bitbucket"
+        self.repo1.save()
+
+        self.get_error_response(status_code=404)
+
+
+class OrganizationSeerProjectRepoDetailsPutTest(APITestCase):
+    endpoint = "sentry-api-0-organization-seer-project-repo-details"
+    method = "put"
+
+    def reverse_url(self):
+        return reverse(
+            self.endpoint,
+            kwargs={
+                "organization_id_or_slug": self.organization.slug,
+                "project_id": self.project.id,
+                "repo_id": self.repo1.id,
+            },
+        )
+
+    def setUp(self) -> None:
+        super().setUp()
+        self.login_as(user=self.user)
+        self.repo1 = self.create_repo(
+            project=self.project,
+            name="getsentry/sentry",
+            provider="integrations:github",
+            external_id="111",
+        )
+
+    def test_update_branch_name(self):
+        self.create_seer_project_repository(self.project, repository=self.repo1, branch_name="main")
+
+        response = self.get_success_response(branchName="develop")
+        assert response.data["branchName"] == "develop"
+
+    def test_update_instructions(self):
+        self.create_seer_project_repository(self.project, repository=self.repo1)
+
+        response = self.get_success_response(instructions="new instructions")
+        assert response.data["instructions"] == "new instructions"
+
+    def test_update_branch_overrides(self):
+        pr = self.create_seer_project_repository(self.project, repository=self.repo1)
+        SeerProjectRepositoryBranchOverride.objects.create(
+            seer_project_repository=pr,
+            tag_name="environment",
+            tag_value="production",
+            branch_name="old-branch",
+        )
+
+        response = self.get_success_response(
+            branchOverrides=[
+                {
+                    "tagName": "environment",
+                    "tagValue": "staging",
+                    "branchName": "staging-branch",
+                }
+            ],
+        )
+        assert len(response.data["branchOverrides"]) == 1
+        assert response.data["branchOverrides"][0]["tagValue"] == "staging"
+
+        assert (
+            SeerProjectRepositoryBranchOverride.objects.filter(seer_project_repository=pr).count()
+            == 1
+        )
+
+    def test_partial_update_preserves_other_fields(self):
+        self.create_seer_project_repository(
+            self.project, repository=self.repo1, branch_name="main", instructions="original"
+        )
+
+        response = self.get_success_response(branchName="develop")
+        assert response.data["branchName"] == "develop"
+        assert response.data["instructions"] == "original"
+
+    def test_partial_update_preserves_branch_overrides(self):
+        project_repo = self.create_seer_project_repository(
+            self.project, repository=self.repo1, branch_name="main"
+        )
+        SeerProjectRepositoryBranchOverride.objects.create(
+            seer_project_repository=project_repo,
+            tag_name="env",
+            tag_value="prod",
+            branch_name="release",
+        )
+
+        response = self.get_success_response(branchName="develop")
+        assert response.data["branchName"] == "develop"
+        assert len(response.data["branchOverrides"]) == 1
+        assert response.data["branchOverrides"][0]["tagName"] == "env"
+        assert response.data["branchOverrides"][0]["branchName"] == "release"
+
+    def test_not_connected_returns_404(self):
+        self.get_error_response(branchName="main", status_code=404)
+
+    def test_set_null_branch_name(self):
+        self.create_seer_project_repository(self.project, repository=self.repo1, branch_name="main")
+
+        response = self.get_success_response(branchName=None)
+        assert response.data["branchName"] is None
+
+    def test_clear_branch_overrides(self):
+        pr = self.create_seer_project_repository(self.project, repository=self.repo1)
+        SeerProjectRepositoryBranchOverride.objects.create(
+            seer_project_repository=pr,
+            tag_name="environment",
+            tag_value="production",
+            branch_name="release",
+        )
+
+        response = self.get_success_response(branchOverrides=[])
+        assert response.data["branchOverrides"] == []
+        assert (
+            SeerProjectRepositoryBranchOverride.objects.filter(seer_project_repository=pr).count()
+            == 0
+        )
+
+    def test_inactive_repo_returns_404(self):
+        self.create_seer_project_repository(self.project, repository=self.repo1)
+        self.repo1.status = ObjectStatus.PENDING_DELETION
+        self.repo1.save()
+
+        self.get_error_response(branchName="develop", status_code=404)
+
+    def test_unsupported_provider_returns_404(self):
+        self.create_seer_project_repository(self.project, repository=self.repo1)
+        self.repo1.provider = "integrations:bitbucket"
+        self.repo1.save()
+
+        self.get_error_response(branchName="develop", status_code=404)
+
+    def test_empty_body_returns_400(self):
+        self.create_seer_project_repository(self.project, repository=self.repo1)
+
+        self.get_error_response(status_code=400)
+
+    def test_duplicate_branch_overrides_returns_400(self):
+        self.create_seer_project_repository(self.project, repository=self.repo1)
+
+        self.get_error_response(
+            branchOverrides=[
+                {"tagName": "environment", "tagValue": "production", "branchName": "release"},
+                {"tagName": "environment", "tagValue": "production", "branchName": "hotfix"},
+            ],
+            status_code=400,
+        )
+
+    def test_branch_overrides_does_not_bump_date_updated(self):
+        project_repo = self.create_seer_project_repository(
+            self.project, repository=self.repo1, branch_name="main"
+        )
+        original_date_updated = project_repo.date_updated
+
+        self.get_success_response(
+            branchOverrides=[
+                {"tagName": "environment", "tagValue": "staging", "branchName": "staging-branch"},
+            ],
+        )
+
+        project_repo.refresh_from_db()
+        assert project_repo.date_updated == original_date_updated
+
+
+class OrganizationSeerProjectRepoDetailsDeleteTest(APITestCase):
+    endpoint = "sentry-api-0-organization-seer-project-repo-details"
+    method = "delete"
+
+    def reverse_url(self):
+        return reverse(
+            self.endpoint,
+            kwargs={
+                "organization_id_or_slug": self.organization.slug,
+                "project_id": self.project.id,
+                "repo_id": self.repo1.id,
+            },
+        )
+
+    def setUp(self) -> None:
+        super().setUp()
+        self.login_as(user=self.user)
+        self.repo1 = self.create_repo(
+            project=self.project,
+            name="getsentry/sentry",
+            provider="integrations:github",
+            external_id="111",
+        )
+
+    def test_delete_repo(self):
+        self.create_seer_project_repository(self.project, repository=self.repo1)
+
+        self.get_success_response()
+        assert not SeerProjectRepository.objects.filter(
+            project_repository__project=self.project,
+            project_repository__repository=self.repo1,
+        ).exists()
+
+    def test_cascades_branch_overrides(self):
+        project_repo = self.create_seer_project_repository(self.project, repository=self.repo1)
+        SeerProjectRepositoryBranchOverride.objects.create(
+            seer_project_repository=project_repo,
+            tag_name="environment",
+            tag_value="production",
+            branch_name="release",
+        )
+
+        self.get_success_response()
+        assert SeerProjectRepositoryBranchOverride.objects.count() == 0
+
+    def test_not_connected_repo_returns_404(self):
+        self.get_error_response(status_code=404)
+
+    def test_inactive_repo_returns_404(self):
+        self.create_seer_project_repository(self.project, repository=self.repo1)
+        self.repo1.status = ObjectStatus.HIDDEN
+        self.repo1.save()
+
+        self.get_error_response(status_code=404)
+
+    def test_unsupported_provider_returns_404(self):
+        self.create_seer_project_repository(self.project, repository=self.repo1)
+        self.repo1.provider = "integrations:bitbucket"
+        self.repo1.save()
+
+        self.get_error_response(status_code=404)