Add 'circleci open' command

The open command was present in the legacy (main) branch but was missed
during the migration to the next branch. This restores the feature,
adapted to the new project structure:

- Detects the project from the git remote (GitHub, Bitbucket, GitLab)
- Opens the CircleCI pipelines page in the default browser
- Uses structured error handling consistent with the new CLI conventions

Author: parkuman

CLAUDE.md

@@ -76,6 +76,7 @@ internal/
 │   ├── config/           circleci config validate/process/pack/generate
 │   ├── context/          circleci context + circleci context secret
 │   ├── job/              circleci job artifacts (deep path; wraps internal/artifacts)
+│   ├── open/             circleci open (opens current project in the CircleCI web UI)
 │   ├── pipeline/         circleci pipeline list/get/trigger
 │   ├── workflow/         circleci workflow list/get/cancel/rerun
 │   ├── orb/              circleci orb list/info/validate/publish/...

internal/cmd/open/open.go

@@ -0,0 +1,87 @@
+// Copyright (c) 2026 Circle Internet Services, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+// SPDX-License-Identifier: MIT
+
+// Package open implements the "circleci open" command.
+package open
+
+import (
+	"fmt"
+	"net/url"
+	"strings"
+
+	"github.com/MakeNowJust/heredoc"
+	"github.com/pkg/browser"
+	"github.com/spf13/cobra"
+
+	clierrors "github.com/CircleCI-Public/circleci-cli-v2/internal/errors"
+	"github.com/CircleCI-Public/circleci-cli-v2/internal/gitremote"
+)
+
+// ProjectURL builds the CircleCI pipelines URL for the given project slug.
+func ProjectURL(slug string) (string, error) {
+	parts := strings.SplitN(slug, "/", 3)
+	if len(parts) != 3 {
+		return "", fmt.Errorf("invalid slug: %q", slug)
+	}
+	return fmt.Sprintf("https://app.circleci.com/pipelines/%s/%s/%s",
+		url.PathEscape(parts[0]),
+		url.PathEscape(parts[1]),
+		url.PathEscape(parts[2]),
+	), nil
+}
+
+// NewOpenCmd returns the "circleci open" command.
+func NewOpenCmd() *cobra.Command {
+	return &cobra.Command{
+		Use:   "open",
+		Short: "Open the current project in the browser",
+		Long: heredoc.Doc(`
+			Open the CircleCI pipelines page for the current project in your
+			default web browser.
+
+			The project is inferred from the current git repository's remote.
+			Supports GitHub, Bitbucket, and GitLab remotes.
+		`),
+		Example: heredoc.Doc(`
+			# Open pipelines for the current repo
+			$ circleci open
+		`),
+		RunE: func(_ *cobra.Command, _ []string) error {
+			info, err := gitremote.Detect()
+			if err != nil {
+				return clierrors.New("git.detect_failed",
+					"Could not detect project from git remote", err.Error()).
+					WithSuggestions(
+						"Run from inside a git repository with a GitHub, Bitbucket, or GitLab remote",
+					).
+					WithExitCode(clierrors.ExitBadArguments)
+			}
+
+			projectURL, err := ProjectURL(info.Slug)
+			if err != nil {
+				return err
+			}
+
+			return browser.OpenURL(projectURL)
+		},
+	}
+}

internal/cmd/open/open_test.go

@@ -0,0 +1,55 @@
+// Copyright (c) 2026 Circle Internet Services, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+// SPDX-License-Identifier: MIT
+
+package open
+
+import (
+	"testing"
+
+	"gotest.tools/v3/assert"
+	"gotest.tools/v3/assert/cmp"
+)
+
+func TestProjectURL(t *testing.T) {
+	t.Run("github project", func(t *testing.T) {
+		got, err := ProjectURL("gh/bar/foo")
+		assert.NilError(t, err)
+		assert.Check(t, cmp.Equal(got, "https://app.circleci.com/pipelines/gh/bar/foo"))
+	})
+
+	t.Run("bitbucket project", func(t *testing.T) {
+		got, err := ProjectURL("bb/myorg/myrepo")
+		assert.NilError(t, err)
+		assert.Check(t, cmp.Equal(got, "https://app.circleci.com/pipelines/bb/myorg/myrepo"))
+	})
+
+	t.Run("gitlab project", func(t *testing.T) {
+		got, err := ProjectURL("gl/my-group/my-project")
+		assert.NilError(t, err)
+		assert.Check(t, cmp.Equal(got, "https://app.circleci.com/pipelines/gl/my-group/my-project"))
+	})
+
+	t.Run("invalid slug", func(t *testing.T) {
+		_, err := ProjectURL("invalid")
+		assert.Check(t, err != nil, "expected error for invalid slug")
+	})
+}

internal/cmd/root/root.go

@@ -36,6 +36,7 @@ import (
 	"github.com/CircleCI-Public/circleci-cli-v2/internal/cmd/envvar"
 	"github.com/CircleCI-Public/circleci-cli-v2/internal/cmd/job"
 	cmdlogs "github.com/CircleCI-Public/circleci-cli-v2/internal/cmd/logs"
+	cmdopen "github.com/CircleCI-Public/circleci-cli-v2/internal/cmd/open"
 	"github.com/CircleCI-Public/circleci-cli-v2/internal/cmd/pipeline"
 	"github.com/CircleCI-Public/circleci-cli-v2/internal/cmd/project"
 	"github.com/CircleCI-Public/circleci-cli-v2/internal/cmd/runner"
@@ -98,6 +99,7 @@ func NewRootCmd(version string) *cobra.Command {
 	cmd.AddCommand(envvar.NewEnvVarCmd())
 	cmd.AddCommand(job.NewJobCmd())
 	cmd.AddCommand(cmdlogs.NewLogsCmd())
+	cmd.AddCommand(cmdopen.NewOpenCmd())
 	cmd.AddCommand(pipeline.NewPipelineCmd())
 	cmd.AddCommand(project.NewProjectCmd())
 	cmd.AddCommand(runner.NewRunnerCmd())

internal/cmd/root/testdata/usage/circleci.txt

@@ -11,6 +11,7 @@ Available Commands:
   job         Manage jobs
   logs        Fetch job logs
   mcp         MCP server management
+  open        Open the current project in the browser
   pipeline    Manage pipelines
   project     Manage CircleCI projects
   runner      Manage self-hosted runners

internal/cmd/root/testdata/usage/circleci/open.txt

@@ -0,0 +1,12 @@
+Usage:
+  circleci open [flags]
+
+Examples:
+# Open pipelines for the current repo
+$ circleci open
+
+
+Global Flags:
+  -c, --config string   path to config file (default: ~/.config/circleci/config.yml)
+      --debug           enable debug logging
+  -q, --quiet           suppress informational output; data on stdout is unaffected