diff --git a/cmd/bob/baseimageconf.go b/cmd/bob/baseimageconf.go
index 030b70c..05cf85b 100644
--- a/cmd/bob/baseimageconf.go
+++ b/cmd/bob/baseimageconf.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/function61/gokit/encoding/jsonfile"
 	"github.com/function61/gokit/os/osutil"
+	"github.com/function61/turbobob/pkg/bobfile"
 )
 
 const (
@@ -16,9 +17,9 @@ const (
 
 // base image conf JSON - able to provide hints for useful commands, setting up cache paths etc.
 type BaseImageConfig struct {
-	DevShellCommands []DevShellCommand `json:"dev_shell_commands"`
-	PathsToCache     []string          `json:"paths_to_cache"` // will be set up as symlinks to a persistent mountpoint, so that subsequent containers benefit from cache
-	Langserver       *LangserverSpec   `json:"langserver"`
+	DevShellCommands []bobfile.DevShellCommand `json:"dev_shell_commands"`
+	PathsToCache     []string                  `json:"paths_to_cache"` // will be set up as symlinks to a persistent mountpoint, so that subsequent containers benefit from cache
+	Langserver       *LangserverSpec           `json:"langserver"`
 
 	FileDescriptionBoilerplate string `json:"for_description_of_this_file_see"` // URL to Bob homepage
 
@@ -54,7 +55,7 @@ func loadBaseImageConfWhenInsideContainer() (*BaseImageConfig, error) {
 
 // non-optional because the implementation makes it a bit hard to check if the file exists
 // (vs. Docker run error), and our current callsite needs non-optional anyway
-func loadNonOptionalBaseImageConf(builder BuilderSpec) (*BaseImageConfig, error) {
+func loadNonOptionalBaseImageConf(builder bobfile.BuilderSpec) (*BaseImageConfig, error) {
 	dockerImage, err := func() (string, error) {
 		kind, data, err := parseBuilderUsesType(builder.Uses)
 		if err != nil {
diff --git a/cmd/bob/build.go b/cmd/bob/build.go
index 6e1e077..2dcdbda 100644
--- a/cmd/bob/build.go
+++ b/cmd/bob/build.go
@@ -11,12 +11,13 @@ import (
 	"time"
 
 	"github.com/function61/gokit/os/osutil"
+	"github.com/function61/turbobob/pkg/bobfile"
 	"github.com/function61/turbobob/pkg/versioncontrol"
 	"github.com/spf13/cobra"
 )
 
 type BuildContext struct {
-	Bobfile           *Bobfile
+	Bobfile           *bobfile.Bobfile
 	OriginDir         string // where the repo exists
 	WorkspaceDir      string // where the revision is being built
 	PublishArtefacts  bool
@@ -31,7 +32,7 @@ type BuildContext struct {
 	IsDefaultBranch   bool   // whether we are in "main" / "master" or equivalent branch
 }
 
-func runBuilder(builder BuilderSpec, buildCtx *BuildContext, opDesc string, cmdToRun []string) error {
+func runBuilder(builder bobfile.BuilderSpec, buildCtx *BuildContext, opDesc string, cmdToRun []string) error {
 	wd, errWd := os.Getwd()
 	if errWd != nil {
 		return errWd
@@ -125,7 +126,7 @@ func runBuilder(builder BuilderSpec, buildCtx *BuildContext, opDesc string, cmdT
 	return nil
 }
 
-func buildAndPushOneDockerImage(dockerImage DockerImageSpec, buildCtx *BuildContext) error {
+func buildAndPushOneDockerImage(dockerImage bobfile.DockerImageSpec, buildCtx *BuildContext) error {
 	tagWithoutVersion := dockerImage.Image
 	tag := tagWithoutVersion + ":" + buildCtx.RevisionId.FriendlyRevisionId
 	tagLatest := tagWithoutVersion + ":latest"
@@ -362,7 +363,7 @@ func build(buildCtx *BuildContext) error {
 	}
 
 	// three-pass process. the flow is well documented in *BuilderCommands* type
-	pass := func(opDesc string, getCommand func(cmds BuilderCommands) []string) error {
+	pass := func(opDesc string, getCommand func(cmds bobfile.BuilderCommands) []string) error {
 		for _, builder := range buildCtx.Bobfile.Builders {
 			if buildCtx.BuilderNameFilter != "" && builder.Name != buildCtx.BuilderNameFilter {
 				continue
@@ -381,9 +382,9 @@ func build(buildCtx *BuildContext) error {
 		return nil
 	}
 
-	preparePass := func(cmds BuilderCommands) []string { return cmds.Prepare }
-	buildPass := func(cmds BuilderCommands) []string { return cmds.Build }
-	publishPass := func(cmds BuilderCommands) []string { return cmds.Publish }
+	preparePass := func(cmds bobfile.BuilderCommands) []string { return cmds.Prepare }
+	buildPass := func(cmds bobfile.BuilderCommands) []string { return cmds.Build }
+	publishPass := func(cmds bobfile.BuilderCommands) []string { return cmds.Publish }
 
 	if err := pass("prepare", preparePass); err != nil {
 		return err // err context ok
@@ -426,7 +427,7 @@ func constructBuildContext(
 	fastBuild bool,
 	areWeInCi bool,
 ) (*BuildContext, error) {
-	bobfile, err := readBobfile()
+	bobfile, err := bobfile.Read()
 	if err != nil {
 		return nil, err
 	}
@@ -579,7 +580,7 @@ func buildInsideEntry() *cobra.Command {
 }
 
 func buildInside(fastBuild bool) error {
-	bobfile, err := readBobfile()
+	bobfile, err := bobfile.Read()
 	if err != nil {
 		return err
 	}
diff --git a/cmd/bob/dev.go b/cmd/bob/dev.go
index 577c8b0..44a8ff4 100644
--- a/cmd/bob/dev.go
+++ b/cmd/bob/dev.go
@@ -11,12 +11,13 @@ import (
 
 	"github.com/function61/gokit/encoding/jsonfile"
 	"github.com/function61/gokit/os/osutil"
+	"github.com/function61/turbobob/pkg/bobfile"
 	"github.com/function61/turbobob/pkg/versioncontrol"
 	"github.com/spf13/cobra"
 )
 
 func devCommand(builderName string, envsAreRequired bool, ignoreNag bool) ([]string, error) {
-	bobfile, err := readBobfile()
+	bobfile, err := bobfile.Read()
 	if err != nil {
 		return nil, err
 	}
@@ -264,7 +265,7 @@ func revisionIdForDev() *versioncontrol.RevisionId {
 	}
 }
 
-func buildArchOnlyForCurrentlyRunningArch(archesToBuildFor OsArchesSpec) OsArchesSpec {
+func buildArchOnlyForCurrentlyRunningArch(archesToBuildFor bobfile.OsArchesSpec) bobfile.OsArchesSpec {
 	devMachineArch := osArchCodeToOsArchesSpec(currentRunningGoOsArchToOsArchCode())
 
 	// to speed up dev, build only for the arch we're running now, but only if arches
diff --git a/cmd/bob/devingress.go b/cmd/bob/devingress.go
index 46e5db6..e3f0a51 100644
--- a/cmd/bob/devingress.go
+++ b/cmd/bob/devingress.go
@@ -4,13 +4,15 @@ import (
 	"fmt"
 	"os"
 	"strings"
+
+	"github.com/function61/turbobob/pkg/bobfile"
 )
 
 // uses Traefik-compliant notation to set up HTTP ingress to route traffic to the dev container
 func setupDevIngress(
-	builder *BuilderSpec,
+	builder *bobfile.BuilderSpec,
 	ingressSettings devIngressSettings,
-	bobfile *Bobfile,
+	bobfile *bobfile.Bobfile,
 ) ([]string, string) {
 	if builder.DevHttpIngress == "" {
 		return nil, ""
diff --git a/cmd/bob/devshim.go b/cmd/bob/devshim.go
index 9463b2f..9d2bd51 100644
--- a/cmd/bob/devshim.go
+++ b/cmd/bob/devshim.go
@@ -12,6 +12,7 @@ import (
 
 	"github.com/function61/gokit/encoding/jsonfile"
 	"github.com/function61/gokit/os/osutil"
+	"github.com/function61/turbobob/pkg/bobfile"
 	"github.com/spf13/cobra"
 )
 
@@ -72,9 +73,9 @@ func shimSetup() error {
 		return err
 	}
 
-	bobfile, err := readBobfile()
+	bobfile, err := bobfile.Read()
 	if err != nil {
-		return fmt.Errorf("readBobfile: %w", err)
+		return err
 	}
 
 	shimConf, err := readShimConfig()
@@ -147,7 +148,7 @@ func shimSetup() error {
 }
 
 // so we can recall frequently needed commands fast + sets up HISTFILE ENV var
-func injectHistory(builder BuilderSpec, alreadyDone bool, baseImgConf BaseImageConfig) error {
+func injectHistory(builder bobfile.BuilderSpec, alreadyDone bool, baseImgConf BaseImageConfig) error {
 	userHomeDir, err := os.UserHomeDir()
 	if err != nil {
 		return err
diff --git a/cmd/bob/docker.go b/cmd/bob/docker.go
index 75d9429..5391cea 100644
--- a/cmd/bob/docker.go
+++ b/cmd/bob/docker.go
@@ -10,6 +10,7 @@ import (
 	"strings"
 
 	. "github.com/function61/gokit/builtin"
+	"github.com/function61/turbobob/pkg/bobfile"
 	"github.com/function61/turbobob/pkg/dockertag"
 	"github.com/function61/turbobob/pkg/versioncontrol"
 )
@@ -24,21 +25,21 @@ func isDevContainerRunning(containerName string) bool {
 	return strings.TrimRight(string(result), "\n") == "true"
 }
 
-func devContainerName(bobfile *Bobfile, builder BuilderSpec) string {
+func devContainerName(bobfile *bobfile.Bobfile, builder bobfile.BuilderSpec) string {
 	return containerNameInternal("dev", bobfile, builder)
 }
 
-func langServerContainerName(bobfile *Bobfile, builder BuilderSpec) string {
+func langServerContainerName(bobfile *bobfile.Bobfile, builder bobfile.BuilderSpec) string {
 	return containerNameInternal("langserver", bobfile, builder)
 }
 
 // do not use directly
-func containerNameInternal(kind string, bobfile *Bobfile, builder BuilderSpec) string {
+func containerNameInternal(kind string, bobfile *bobfile.Bobfile, builder bobfile.BuilderSpec) string {
 	return fmt.Sprintf("tb%s-%s-%s", kind, bobfile.ProjectName, builder.Name)
 
 }
 
-func builderImageName(bobfile *Bobfile, builder BuilderSpec) string {
+func builderImageName(bobfile *bobfile.Bobfile, builder bobfile.BuilderSpec) string {
 	builderType, ref, err := parseBuilderUsesType(builder.Uses)
 	if err != nil {
 		panic(err)
@@ -54,7 +55,7 @@ func builderImageName(bobfile *Bobfile, builder BuilderSpec) string {
 	}
 }
 
-func buildBuilder(bobfile *Bobfile, builder *BuilderSpec) error {
+func buildBuilder(bobfile *bobfile.Bobfile, builder *bobfile.BuilderSpec) error {
 	imageName := builderImageName(bobfile, *builder)
 
 	builderUsesType, dockerfilePath, err := parseBuilderUsesType(builder.Uses)
@@ -114,9 +115,9 @@ func buildBuilder(bobfile *Bobfile, builder *BuilderSpec) error {
 func dockerRelayEnvVars(
 	dockerArgs []string,
 	revisionId *versioncontrol.RevisionId,
-	builder BuilderSpec,
+	builder bobfile.BuilderSpec,
 	envsAreRequired bool,
-	osArches OsArchesSpec,
+	osArches bobfile.OsArchesSpec,
 	fastbuild bool,
 	debug bool,
 ) ([]string, error) {
@@ -166,7 +167,7 @@ func dockerRelayEnvVars(
 	return dockerArgs, nil
 }
 
-func loginToDockerRegistry(dockerImage DockerImageSpec, cache *dockerRegistryLoginCache) error {
+func loginToDockerRegistry(dockerImage bobfile.DockerImageSpec, cache *dockerRegistryLoginCache) error {
 	credentialsObtainer := getDockerCredentialsObtainer(dockerImage)
 	creds, err := credentialsObtainer.Obtain()
 	if err != nil {
@@ -179,7 +180,7 @@ func loginToDockerRegistry(dockerImage DockerImageSpec, cache *dockerRegistryLog
 
 	tagParsed := dockertag.Parse(dockerImage.Image)
 	if tagParsed == nil {
-		return ErrUnableToParseDockerTag
+		return bobfile.ErrUnableToParseDockerTag
 	}
 
 	registryDefaulted := tagParsed.Registry
diff --git a/cmd/bob/dockercredentials.go b/cmd/bob/dockercredentials.go
index dd6a755..b496396 100644
--- a/cmd/bob/dockercredentials.go
+++ b/cmd/bob/dockercredentials.go
@@ -4,6 +4,8 @@ import (
 	"errors"
 	"os"
 	"regexp"
+
+	"github.com/function61/turbobob/pkg/bobfile"
 )
 
 type DockerCredentials struct {
@@ -28,7 +30,7 @@ func (d *credsFromENV) Obtain() (*DockerCredentials, error) {
 
 	credsParts := credsFromENVRe.FindStringSubmatch(serialized)
 	if len(credsParts) != 3 {
-		return nil, ErrInvalidDockerCredsEnvFormat
+		return nil, bobfile.ErrInvalidDockerCredsEnvFormat
 	}
 
 	return &DockerCredentials{
@@ -37,7 +39,7 @@ func (d *credsFromENV) Obtain() (*DockerCredentials, error) {
 	}, nil
 }
 
-func getDockerCredentialsObtainer(dockerImage DockerImageSpec) DockerCredentialObtainer {
+func getDockerCredentialsObtainer(dockerImage bobfile.DockerImageSpec) DockerCredentialObtainer {
 	if dockerImage.AuthType == nil {
 		return &credsFromENV{}
 	}
diff --git a/cmd/bob/init.go b/cmd/bob/init.go
index 23ddffb..f7499eb 100644
--- a/cmd/bob/init.go
+++ b/cmd/bob/init.go
@@ -9,6 +9,7 @@ import (
 
 	. "github.com/function61/gokit/builtin"
 	"github.com/function61/gokit/os/osutil"
+	"github.com/function61/turbobob/pkg/bobfile"
 	"github.com/spf13/cobra"
 )
 
@@ -82,26 +83,26 @@ func writeDefaultBobfile(producesDockerImage bool) error {
 	// guess project name from current workdir's basename
 	projectName := filepath.Base(cwd)
 
-	dockerImages := []DockerImageSpec{}
+	dockerImages := []bobfile.DockerImageSpec{}
 	if producesDockerImage {
-		dockerImages = append(dockerImages, DockerImageSpec{
+		dockerImages = append(dockerImages, bobfile.DockerImageSpec{
 			Image:          "yourcompany/" + projectName,
 			DockerfilePath: "Dockerfile",
 		})
 	}
 
-	defaults := Bobfile{
-		FileDescriptionBoilerplate: fileDescriptionBoilerplate,
-		VersionMajor:               currentVersionMajor,
+	defaults := bobfile.Bobfile{
+		FileDescriptionBoilerplate: bobfile.FileDescriptionBoilerplate,
+		VersionMajor:               bobfile.CurrentVersionMajor,
 		ProjectName:                projectName,
-		Builders: []BuilderSpec{
+		Builders: []bobfile.BuilderSpec{
 			{
 				Name:             "default",
 				Uses:             "dockerfile://build-default.Dockerfile",
 				MountSource:      "",
 				MountDestination: "/app",
 				PassEnvs:         []string{},
-				Commands: BuilderCommands{
+				Commands: bobfile.BuilderCommands{
 					Dev: []string{"bash"},
 				},
 				DevProTips:       []string{},
@@ -115,14 +116,14 @@ func writeDefaultBobfile(producesDockerImage bool) error {
 	return writeBobfileIfNotExists(defaults)
 }
 
-func writeBobfileIfNotExists(content Bobfile) error {
-	exists, errExistsCheck := osutil.Exists(bobfileName)
+func writeBobfileIfNotExists(content bobfile.Bobfile) error {
+	exists, errExistsCheck := osutil.Exists(bobfile.Name)
 	if errExistsCheck != nil {
 		return errExistsCheck
 	}
 
 	if exists {
-		return ErrInitBobfileExists
+		return bobfile.ErrInitBobfileExists
 	}
 
 	asJson, errJson := json.MarshalIndent(&content, "", "\t")
@@ -130,12 +131,12 @@ func writeBobfileIfNotExists(content Bobfile) error {
 		return errJson
 	}
 
-	if err := os.MkdirAll(filepath.Dir(bobfileName), 0755); err != nil {
+	if err := os.MkdirAll(filepath.Dir(bobfile.Name), 0755); err != nil {
 		return err
 	}
 
 	return ioutil.WriteFile(
-		bobfileName,
+		bobfile.Name,
 		[]byte(fmt.Sprintf("%s\n", asJson)),
 		osutil.FileMode(osutil.OwnerRW, osutil.GroupRW, osutil.OtherNone))
 }
diff --git a/cmd/bob/initguess.go b/cmd/bob/initguess.go
index d815b49..e784481 100644
--- a/cmd/bob/initguess.go
+++ b/cmd/bob/initguess.go
@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 
 	. "github.com/function61/gokit/builtin"
+	"github.com/function61/turbobob/pkg/bobfile"
 	"github.com/moby/buildkit/frontend/dockerfile/instructions"
 	"github.com/moby/buildkit/frontend/dockerfile/parser"
 )
@@ -63,16 +64,16 @@ func initGuessFromDockerfile() error {
 		return err
 	}
 
-	return writeBobfileIfNotExists(Bobfile{
-		FileDescriptionBoilerplate: fileDescriptionBoilerplate,
-		VersionMajor:               currentVersionMajor,
+	return writeBobfileIfNotExists(bobfile.Bobfile{
+		FileDescriptionBoilerplate: bobfile.FileDescriptionBoilerplate,
+		VersionMajor:               bobfile.CurrentVersionMajor,
 		ProjectName:                projectName,
-		Builders: []BuilderSpec{
+		Builders: []bobfile.BuilderSpec{
 			{
 				Name:             "default",
 				Uses:             "docker://" + builderStage.BaseName,
 				MountDestination: copyCommand.DestPath,
-				Commands: BuilderCommands{
+				Commands: bobfile.BuilderCommands{
 					Build: buildCommand,
 					Dev:   []string{"bash"}, // just a guess
 				},
diff --git a/cmd/bob/langserver.go b/cmd/bob/langserver.go
index ec668e7..b201e3c 100644
--- a/cmd/bob/langserver.go
+++ b/cmd/bob/langserver.go
@@ -13,6 +13,7 @@ import (
 
 	"github.com/function61/gokit/os/osutil"
 	"github.com/function61/gokit/sliceutil"
+	"github.com/function61/turbobob/pkg/bobfile"
 	"github.com/spf13/cobra"
 )
 
@@ -58,13 +59,13 @@ func langserverRunShim(ctx context.Context, langs []string) error {
 	mountDir := workdir
 
 	// access chosen project's details (so we know which programming language's langserver to start)
-	bobfile, err := readBobfile()
+	projectFile, err := bobfile.Read()
 	if err != nil {
 		return err
 	}
 
-	langserverCmd, builder, err := func() ([]string, *BuilderSpec, error) {
-		for _, builder := range bobfile.Builders {
+	langserverCmd, builder, err := func() ([]string, *bobfile.BuilderSpec, error) {
+		for _, builder := range projectFile.Builders {
 			// FIXME: this assumes
 			baseImageConf, err := loadNonOptionalBaseImageConf(builder)
 			if err != nil {
@@ -82,7 +83,7 @@ func langserverRunShim(ctx context.Context, langs []string) error {
 
 		return nil, nil, fmt.Errorf(
 			"%s doesn't define a compatible language server for %v",
-			bobfile.ProjectName,
+			projectFile.ProjectName,
 			langs)
 	}()
 	if err != nil {
@@ -99,7 +100,7 @@ func langserverRunShim(ctx context.Context, langs []string) error {
 		"--rm", // so resources get released. (this process is ephemeral in nature)
 		"--shm-size=512M",
 		"--interactive", // use stdin (it is the transport for one direction in LSP)
-		"--name=" + langServerContainerName(bobfile, *builder),
+		"--name=" + langServerContainerName(projectFile, *builder),
 		"--volume", fmt.Sprintf("%s:%s", workdir, mountDir),
 		dockerImage,
 	}, langserverCmd...)
diff --git a/cmd/bob/osarchcodes.go b/cmd/bob/osarchcodes.go
index 7093062..52c1086 100644
--- a/cmd/bob/osarchcodes.go
+++ b/cmd/bob/osarchcodes.go
@@ -1,5 +1,9 @@
 package main
 
+import (
+	"github.com/function61/turbobob/pkg/bobfile"
+)
+
 // looks like "linux-amd64" (JSON keys in OsArchesSpec). need to add to
 // - OsArchesSpec
 // - AsBuildEnvVariables()
@@ -8,31 +12,31 @@ package main
 type OsArchCode string
 
 // TODO: a test that guarantees that this is in sync with OsArchesSpec?
-func osArchCodeToOsArchesSpec(code OsArchCode) OsArchesSpec {
+func osArchCodeToOsArchesSpec(code OsArchCode) bobfile.OsArchesSpec {
 	switch code {
 	case "neutral":
-		return OsArchesSpec{Neutral: true}
+		return bobfile.OsArchesSpec{Neutral: true}
 	case "linux-neutral":
-		return OsArchesSpec{LinuxNeutral: true}
+		return bobfile.OsArchesSpec{LinuxNeutral: true}
 	case "linux-amd64":
-		return OsArchesSpec{LinuxAmd64: true}
+		return bobfile.OsArchesSpec{LinuxAmd64: true}
 	case "linux-arm":
-		return OsArchesSpec{LinuxArm: true}
+		return bobfile.OsArchesSpec{LinuxArm: true}
 	case "linux-arm64":
-		return OsArchesSpec{LinuxArm64: true}
+		return bobfile.OsArchesSpec{LinuxArm64: true}
 	case "windows-neutral":
-		return OsArchesSpec{WindowsNeutral: true}
+		return bobfile.OsArchesSpec{WindowsNeutral: true}
 	case "windows-amd64":
-		return OsArchesSpec{WindowsAmd64: true}
+		return bobfile.OsArchesSpec{WindowsAmd64: true}
 	case "darwin-amd64":
-		return OsArchesSpec{DarwinAmd64: true}
+		return bobfile.OsArchesSpec{DarwinAmd64: true}
 	default:
-		return OsArchesSpec{}
+		return bobfile.OsArchesSpec{}
 	}
 }
 
 // TODO: a test that guarantees that this is in sync with OsArchesSpec?
-func osArchesIntersects(a OsArchesSpec, b OsArchesSpec) bool {
+func osArchesIntersects(a bobfile.OsArchesSpec, b bobfile.OsArchesSpec) bool {
 	return a.Neutral && b.Neutral ||
 		a.LinuxNeutral && b.LinuxNeutral ||
 		a.LinuxAmd64 && b.LinuxAmd64 ||
diff --git a/cmd/bob/quality.go b/cmd/bob/quality.go
index de7ba83..243e461 100644
--- a/cmd/bob/quality.go
+++ b/cmd/bob/quality.go
@@ -5,9 +5,11 @@ import (
 	"fmt"
 	"os"
 	"strings"
+
+	"github.com/function61/turbobob/pkg/bobfile"
 )
 
-func qualityCheckBuilderUsesExpect(rules map[string]string, bobfile *Bobfile) error {
+func qualityCheckBuilderUsesExpect(rules map[string]string, bobfile *bobfile.Bobfile) error {
 	for _, builder := range bobfile.Builders {
 		for substring, expectFull := range rules {
 			if strings.Contains(builder.Uses, substring) && builder.Uses != expectFull {
diff --git a/cmd/bob/subrepo.go b/cmd/bob/subrepo.go
index 6f1b94f..9092dde 100644
--- a/cmd/bob/subrepo.go
+++ b/cmd/bob/subrepo.go
@@ -4,10 +4,11 @@ import (
 	"fmt"
 
 	"github.com/function61/gokit/os/osutil"
+	"github.com/function61/turbobob/pkg/bobfile"
 	"github.com/function61/turbobob/pkg/versioncontrol"
 )
 
-func ensureSubrepoCloned(destination string, subrepo SubrepoSpec) error {
+func ensureSubrepoCloned(destination string, subrepo bobfile.SubrepoSpec) error {
 	exists, err := osutil.Exists(destination)
 	if err != nil {
 		return err
diff --git a/cmd/bob/tips.go b/cmd/bob/tips.go
index 4e8e9c9..717e6b4 100644
--- a/cmd/bob/tips.go
+++ b/cmd/bob/tips.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	"github.com/function61/gokit/os/osutil"
+	"github.com/function61/turbobob/pkg/bobfile"
 	"github.com/scylladb/termtables"
 	"github.com/spf13/cobra"
 )
@@ -20,7 +21,7 @@ func tipsEntry() *cobra.Command {
 }
 
 func tips() error {
-	bobfile, err := readBobfile()
+	bobfile, err := bobfile.Read()
 	if err != nil {
 		return err
 	}
diff --git a/cmd/bob/utils.go b/cmd/bob/utils.go
index e658534..18630cb 100644
--- a/cmd/bob/utils.go
+++ b/cmd/bob/utils.go
@@ -1,12 +1,15 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"os"
 	"os/exec"
 	"strings"
 	"sync"
+
+	"github.com/function61/turbobob/pkg/bobfile"
 )
 
 func passthroughStdoutAndStderr(cmd *exec.Cmd) *exec.Cmd {
@@ -20,7 +23,11 @@ func isEnvVarPresent(key string) bool {
 	return os.Getenv(key) != ""
 }
 
-func allDevShellCommands(devShellCommands []DevShellCommand) []string {
+func envVarMissingErr(envKey string) error {
+	return errors.New("ENV var missing: " + envKey)
+}
+
+func allDevShellCommands(devShellCommands []bobfile.DevShellCommand) []string {
 	commands := []string{}
 	for _, command := range devShellCommands {
 		commands = append(commands, command.Command)
@@ -40,6 +47,16 @@ func must(input builderUsesType, _ string, err error) builderUsesType {
 	return input
 }
 
+func findBuilder(projectFile *bobfile.Bobfile, builderName string) (*bobfile.BuilderSpec, error) {
+	for _, builder := range projectFile.Builders {
+		if builder.Name == builderName {
+			return &builder, nil
+		}
+	}
+
+	return nil, bobfile.ErrBuilderNotFound
+}
+
 func withLogLineGroup(group string, work func() error) error {
 	if !runningInGitHubActions() {
 		printHeading(group)
diff --git a/cmd/bob/workspace.go b/cmd/bob/workspace.go
index 8f489f1..24fc3f8 100755
--- a/cmd/bob/workspace.go
+++ b/cmd/bob/workspace.go
@@ -12,6 +12,7 @@ import (
 	"os"
 
 	"github.com/function61/gokit/os/osutil"
+	"github.com/function61/turbobob/pkg/bobfile"
 	"github.com/spf13/cobra"
 )
 
@@ -97,7 +98,7 @@ func workspaceLaunchFileBrowser() error {
 }
 
 func workspaceRenameToSelectedProject() error {
-	bobfile, err := readBobfile()
+	bobfile, err := bobfile.Read()
 	if err != nil {
 		return err
 	}
diff --git a/cmd/bob/bobfile.go b/pkg/bobfile/bobfile.go
similarity index 92%
rename from cmd/bob/bobfile.go
rename to pkg/bobfile/bobfile.go
index 5f0f25b..51510ea 100644
--- a/cmd/bob/bobfile.go
+++ b/pkg/bobfile/bobfile.go
@@ -1,4 +1,5 @@
-package main
+// Project configuration file for Turbo Bob
+package bobfile
 
 import (
 	"errors"
@@ -13,12 +14,12 @@ import (
 )
 
 const (
-	bobfileName                = ".config/turbobob.json"
-	fileDescriptionBoilerplate = "https://github.com/function61/turbobob"
+	Name                       = ".config/turbobob.json"
+	FileDescriptionBoilerplate = "https://github.com/function61/turbobob"
 )
 
 const (
-	currentVersionMajor = 1
+	CurrentVersionMajor = 1
 )
 
 type Bobfile struct {
@@ -166,9 +167,11 @@ type DockerImageSpec struct {
 
 // FIXME: Bobfile should actually be read only after correct
 // revision has been checked out from VCs
-func readBobfile() (*Bobfile, error) {
+func Read() (*Bobfile, error) {
+	withErr := func(err error) (*Bobfile, error) { return nil, fmt.Errorf("bobfile.Read: %w", err) }
+
 	bobfileFile, err := func() (io.ReadCloser, error) {
-		bobfileFile, err := os.Open(bobfileName)
+		bobfileFile, err := os.Open(Name)
 		if err != nil && errors.Is(err, fs.ErrNotExist) { // try old filename
 			return os.Open("turbobob.json")
 		}
@@ -177,28 +180,28 @@ func readBobfile() (*Bobfile, error) {
 	}()
 	if err != nil {
 		if errors.Is(err, fs.ErrNotExist) {
-			return nil, ErrBobfileNotFound
+			return withErr(ErrBobfileNotFound)
 		} else {
-			return nil, err
+			return withErr(err)
 		}
 	}
 	defer bobfileFile.Close()
 
 	bobfile := &Bobfile{}
 	if err := jsonfile.UnmarshalDisallowUnknownFields(bobfileFile, bobfile); err != nil {
-		return nil, err
+		return withErr(err)
 	}
 
-	if bobfile.VersionMajor != currentVersionMajor {
-		return nil, ErrUnsupportedBobfileVersion
+	if bobfile.VersionMajor != CurrentVersionMajor {
+		return withErr(ErrUnsupportedBobfileVersion)
 	}
 
-	if bobfile.FileDescriptionBoilerplate != fileDescriptionBoilerplate {
-		return nil, ErrIncorrectFileDescriptionBp
+	if bobfile.FileDescriptionBoilerplate != FileDescriptionBoilerplate {
+		return withErr(ErrIncorrectFileDescriptionBp)
 	}
 
 	if err := validateBuilders(bobfile); err != nil {
-		return nil, ErrorWrap("validateBuilders", err)
+		return withErr(ErrorWrap("validateBuilders", err))
 	}
 
 	for _, subrepo := range bobfile.Subrepos {
@@ -207,7 +210,7 @@ func readBobfile() (*Bobfile, error) {
 		// the value is missing, the func does not get called. IOW unmarshaling can still
 		// end up in broken data, so we must check it manually..
 		if err := ErrorIfUnset(subrepo.Kind == "", "subrepo.Kind"); err != nil {
-			return nil, err
+			return withErr(err)
 		}
 	}
 
@@ -235,13 +238,3 @@ func validateBuilders(bobfile *Bobfile) error {
 
 	return nil
 }
-
-func findBuilder(bobfile *Bobfile, builderName string) (*BuilderSpec, error) {
-	for _, builder := range bobfile.Builders {
-		if builder.Name == builderName {
-			return &builder, nil
-		}
-	}
-
-	return nil, ErrBuilderNotFound
-}
diff --git a/cmd/bob/errors.go b/pkg/bobfile/errors.go
similarity index 78%
rename from cmd/bob/errors.go
rename to pkg/bobfile/errors.go
index c7b90d7..a6386a5 100644
--- a/cmd/bob/errors.go
+++ b/pkg/bobfile/errors.go
@@ -1,4 +1,4 @@
-package main
+package bobfile
 
 import (
 	"errors"
@@ -14,6 +14,11 @@ var (
 	ErrIncorrectFileDescriptionBp  = errors.New("you are not supposed to change FileDescriptionBoilerplate")
 )
 
-func envVarMissingErr(envKey string) error {
-	return errors.New("ENV var missing: " + envKey)
+// tech debt: can't update to newer Go to use this func from gokit
+func firstNonEmpty(a, b string) string {
+	if a != "" {
+		return a
+	} else {
+		return b
+	}
 }