diff --git a/.github/workflows/golangci-lint.yaml b/.github/workflows/golangci-lint.yaml
index d8eed7c..b43ac98 100644
--- a/.github/workflows/golangci-lint.yaml
+++ b/.github/workflows/golangci-lint.yaml
@@ -39,4 +39,4 @@ jobs:
       - name: Run golangci-lint
         uses: golangci/golangci-lint-action@ba0d7d2ec06a0ea1cb5fa41b2e4a3ab91d21278a # v9.3.0
         with:
-          version: v2.11
+          version: v2.12
diff --git a/.golangci.yaml b/.golangci.yaml
index 4099eb2..f42d5a3 100644
--- a/.golangci.yaml
+++ b/.golangci.yaml
@@ -60,7 +60,7 @@ linters:
     - godox
     - goheader
     - gomoddirectives
-    - gomodguard
+    - gomodguard_v2
     - goprintffuncname
     - gosec
     - gosmopolitan
@@ -110,6 +110,9 @@ linters:
     - zerologlint
 
   settings:
+    goconst:
+      # Repeated literals in table driven tests don't warrant constants.
+      ignore-tests: true
     gocyclo:
       min-complexity: 35
     godox:
diff --git a/internal/cmd/audit.go b/internal/cmd/audit.go
index 1ce3e93..08a32fe 100644
--- a/internal/cmd/audit.go
+++ b/internal/cmd/audit.go
@@ -23,6 +23,9 @@ const (
 const (
 	statusPassed = "passed"
 	statusFailed = "failed"
+
+	auditModeBasicName = "basic"
+	auditModeFullName  = "full"
 )
 
 // Enable audit mode enum
@@ -30,9 +33,9 @@ const (
 func (e *AuditMode) String() string {
 	switch *e {
 	case AuditModeBasic:
-		return "basic"
+		return auditModeBasicName
 	case AuditModeFull:
-		return "full"
+		return auditModeFullName
 	}
 	return "error"
 }
@@ -40,14 +43,14 @@ func (e *AuditMode) String() string {
 // Set must have pointer receiver so it doesn't change the value of a copy
 func (e *AuditMode) Set(v string) error {
 	switch v {
-	case "basic":
+	case auditModeBasicName:
 		*e = AuditModeBasic
 		return nil
-	case "full":
+	case auditModeFullName:
 		*e = AuditModeFull
 		return nil
 	default:
-		return errors.New(`must be one of "foo", "bar", or "moo"`)
+		return fmt.Errorf("must be one of %q or %q", auditModeBasicName, auditModeFullName)
 	}
 }
 
@@ -119,7 +122,7 @@ func addAudit(parentCmd *cobra.Command) {
 	opts := &auditOpts{}
 	auditCmd := &cobra.Command{
 		Use:     "audit",
-		GroupID: "verification",
+		GroupID: cmdGroupVerification,
 		Short:   "Verifies multiple commits in the branch history",
 		Long: `Checks the revisions on the specified branch within the repository.
 
diff --git a/internal/cmd/auth.go b/internal/cmd/auth.go
index c258d07..525d9d4 100644
--- a/internal/cmd/auth.go
+++ b/internal/cmd/auth.go
@@ -18,7 +18,7 @@ var colorHiRed = color.New(color.FgHiRed).SprintFunc()
 
 func addAuth(parentCmd *cobra.Command) {
 	authCmd := &cobra.Command{
-		GroupID:       "configuration",
+		GroupID:       cmdGroupConfiguration,
 		Short:         "Manage user authentication",
 		Use:           "auth",
 		SilenceUsage:  false,
diff --git a/internal/cmd/checklevel.go b/internal/cmd/checklevel.go
index a8a4520..be8c3e6 100644
--- a/internal/cmd/checklevel.go
+++ b/internal/cmd/checklevel.go
@@ -44,7 +44,7 @@ func addCheckLevel(parentCmd *cobra.Command) {
 
 	checklevelCmd := &cobra.Command{
 		Use:     "checklevel",
-		GroupID: "assessment",
+		GroupID: cmdGroupAssessment,
 		Short:   "Determines the SLSA Source Level of the repo",
 		Long: `Determines the SLSA Source Level of the repo.
 
diff --git a/internal/cmd/checklevelprov.go b/internal/cmd/checklevelprov.go
index de6ca3e..96643ca 100644
--- a/internal/cmd/checklevelprov.go
+++ b/internal/cmd/checklevelprov.go
@@ -89,7 +89,7 @@ func addCheckLevelProv(parentCmd *cobra.Command) {
 
 	checklevelprovCmd := &cobra.Command{
 		Use:     "checklevelprov",
-		GroupID: "assessment",
+		GroupID: cmdGroupAssessment,
 		Example: `sourcetool checklevelprov owner/repo --push=note`,
 		Short:   "Checks the given commit against policy using & creating provenance",
 		Long: `Checks the given commit against policy using & creating provenance.
diff --git a/internal/cmd/checktag.go b/internal/cmd/checktag.go
index 0e3154f..fa1b28c 100644
--- a/internal/cmd/checktag.go
+++ b/internal/cmd/checktag.go
@@ -55,7 +55,7 @@ func addCheckTag(parentCmd *cobra.Command) {
 
 	checktagCmd := &cobra.Command{
 		Use:     "checktag",
-		GroupID: "assessment",
+		GroupID: cmdGroupAssessment,
 		Short:   "Checks to see if the tag operation should be allowed and issues a VSA",
 		PreRunE: func(cmd *cobra.Command, args []string) error {
 			if len(args) > 0 {
diff --git a/internal/cmd/createpolicy.go b/internal/cmd/createpolicy.go
index 101592b..8f87f3f 100644
--- a/internal/cmd/createpolicy.go
+++ b/internal/cmd/createpolicy.go
@@ -31,7 +31,7 @@ func addCreatePolicy(parentCmd *cobra.Command) {
 
 	createpolicyCmd := &cobra.Command{
 		Use:     "createpolicy",
-		GroupID: "policy",
+		GroupID: cmdGroupPolicy,
 		Short:   "Creates a policy in a local copy of source-policies",
 		Long: `Creates a SLSA source policy in a local copy of source-policies.
 
diff --git a/internal/cmd/policy.go b/internal/cmd/policy.go
index b0da20b..1751fa8 100644
--- a/internal/cmd/policy.go
+++ b/internal/cmd/policy.go
@@ -39,7 +39,7 @@ func (pco *policyCreateOpts) AddFlags(cmd *cobra.Command) {
 
 func addPolicy(parentCmd *cobra.Command) {
 	policyCmd := &cobra.Command{
-		GroupID: "policy",
+		GroupID: cmdGroupPolicy,
 		Short:   "tools to work with source policies",
 		Long: fmt.Sprintf(`
 %s %s
diff --git a/internal/cmd/prov.go b/internal/cmd/prov.go
index 1555c2c..0da64ce 100644
--- a/internal/cmd/prov.go
+++ b/internal/cmd/prov.go
@@ -39,7 +39,7 @@ func addProv(parentCmd *cobra.Command) {
 	opts := provOptions{}
 	provCmd := &cobra.Command{
 		Use:     "prov",
-		GroupID: "assessment",
+		GroupID: cmdGroupAssessment,
 		Short:   "Creates provenance for the given commit, but does not check policy.",
 		PreRunE: func(cmd *cobra.Command, args []string) error {
 			if len(args) > 0 {
diff --git a/internal/cmd/root.go b/internal/cmd/root.go
index a395c19..5713652 100644
--- a/internal/cmd/root.go
+++ b/internal/cmd/root.go
@@ -15,16 +15,13 @@ import (
 
 var githubToken string
 
-// func getVerifier(vo *verifierOptions) attest.Verifier {
-// 	options := attest.DefaultVerifierOptions
-// 	if vo.expectedIssuer != "" {
-// 		options.ExpectedIssuer = vo.expectedIssuer
-// 	}
-// 	if vo.expectedSan != "" {
-// 		options.ExpectedSan = vo.expectedSan
-// 	}
-// 	return attest.NewBndVerifier(options)
-// }
+// Command group IDs used to organize the subcommands in the help screen.
+const (
+	cmdGroupVerification  = "verification"
+	cmdGroupAssessment    = "assessment"
+	cmdGroupPolicy        = "policy"
+	cmdGroupConfiguration = "configuration"
+)
 
 // exitError wraps an error together with an exit code so commands can
 // signal other failuresdistinct from a generic failure (exit 1).
@@ -58,19 +55,19 @@ controls and much more.
 	// Define command groups for better organization
 	rootCmd.AddGroup(
 		&cobra.Group{
-			ID:    "verification",
+			ID:    cmdGroupVerification,
 			Title: "Verification Commands:",
 		},
 		&cobra.Group{
-			ID:    "assessment",
+			ID:    cmdGroupAssessment,
 			Title: "Assessment Commands:",
 		},
 		&cobra.Group{
-			ID:    "policy",
+			ID:    cmdGroupPolicy,
 			Title: "Policy Commands:",
 		},
 		&cobra.Group{
-			ID:    "configuration",
+			ID:    cmdGroupConfiguration,
 			Title: "Configuration & Setup Commands:",
 		},
 	)
diff --git a/internal/cmd/setup.go b/internal/cmd/setup.go
index f966c6a..7d15520 100644
--- a/internal/cmd/setup.go
+++ b/internal/cmd/setup.go
@@ -52,7 +52,7 @@ func (so *setupOpts) Validate() error {
 
 func addSetup(parentCmd *cobra.Command) {
 	setupCmd := &cobra.Command{
-		GroupID: "configuration",
+		GroupID: cmdGroupConfiguration,
 		Short:   "configure SLSA source features in a repository",
 		Long: fmt.Sprintf(`
 %s %s
diff --git a/internal/cmd/status.go b/internal/cmd/status.go
index ff080ae..9d0cad4 100644
--- a/internal/cmd/status.go
+++ b/internal/cmd/status.go
@@ -47,7 +47,7 @@ func (so *statusOptions) AddFlags(cmd *cobra.Command) {
 func addStatus(parentCmd *cobra.Command) {
 	opts := &statusOptions{}
 	statusCmd := &cobra.Command{
-		GroupID: "assessment",
+		GroupID: cmdGroupAssessment,
 		Short:   "Check the SLSA Source status of a repo/branch",
 		Long: `
 sourcetool status: Check the SLSA Source status of a repo/branch
diff --git a/internal/cmd/verifycommit.go b/internal/cmd/verifycommit.go
index 6bc4982..4645185 100644
--- a/internal/cmd/verifycommit.go
+++ b/internal/cmd/verifycommit.go
@@ -18,6 +18,12 @@ type verifyCommitOptions struct {
 	revisionOpts
 }
 
+// Ref types reported in the verification results
+const (
+	refTypeBranch = "branch"
+	refTypeTag    = "tag"
+)
+
 // VerifyCommitResult represents the result of a commit verification
 type VerifyCommitResult struct {
 	Success        bool     `json:"success"`
@@ -58,7 +64,7 @@ func addVerifyCommit(cmd *cobra.Command) {
 	opts := verifyCommitOptions{}
 	verifyCommitCmd := &cobra.Command{
 		Use:     "verifycommit",
-		GroupID: "verification",
+		GroupID: cmdGroupVerification,
 		Short:   "Verifies the specified commit is valid",
 		PreRunE: func(cmd *cobra.Command, args []string) error {
 			if len(args) > 0 {
@@ -101,10 +107,10 @@ func addVerifyCommit(cmd *cobra.Command) {
 			var refName string
 			switch {
 			case opts.branch != "":
-				refType = "branch"
+				refType = refTypeBranch
 				refName = opts.branch
 			case opts.tag != "":
-				refType = "tag"
+				refType = refTypeTag
 				refName = opts.tag
 			default:
 				return fmt.Errorf("must specify either branch or tag")
diff --git a/pkg/attest/attester.go b/pkg/attest/attester.go
index 2e0a42a..07a26aa 100644
--- a/pkg/attest/attester.go
+++ b/pkg/attest/attester.go
@@ -206,7 +206,7 @@ func addPredToStatement(provPred proto.Message, predicateType, commit string) (*
 	}
 
 	sub := []*intoto.ResourceDescriptor{{
-		Digest: map[string]string{"gitCommit": commit},
+		Digest: map[string]string{models.DigestTypeGitCommit: commit},
 	}}
 
 	var predPb structpb.Struct
diff --git a/pkg/attest/statement.go b/pkg/attest/statement.go
index 979bf0e..b8409bb 100644
--- a/pkg/attest/statement.go
+++ b/pkg/attest/statement.go
@@ -48,12 +48,12 @@ func GetSubjectForCommit(att attestation.Envelope, commit *models.Commit) *intot
 		if !ok {
 			continue
 		}
-		val, ok := rd.GetDigest()["gitCommit"]
+		val, ok := rd.GetDigest()[models.DigestTypeGitCommit]
 		if ok && val == commit.SHA {
 			return rd
 		}
 
-		if val, ok = rd.GetDigest()["sha1"]; ok && val == commit.SHA {
+		if val, ok = rd.GetDigest()[models.DigestTypeSha1]; ok && val == commit.SHA {
 			fromSha = rd
 		}
 	}
diff --git a/pkg/attest/vsa.go b/pkg/attest/vsa.go
index bdff404..dcab259 100644
--- a/pkg/attest/vsa.go
+++ b/pkg/attest/vsa.go
@@ -51,7 +51,7 @@ func createUnsignedSourceVsaAllParams(branch *models.Branch, commit *models.Comm
 		return "", fmt.Errorf("creating struct from map: %w", err)
 	}
 	sub := []*spb.ResourceDescriptor{{
-		Digest:      map[string]string{"gitCommit": commit.SHA},
+		Digest:      map[string]string{models.DigestTypeGitCommit: commit.SHA},
 		Annotations: annotationStruct,
 	}}
 
diff --git a/pkg/policy/policy.go b/pkg/policy/policy.go
index 8bab65d..766228e 100644
--- a/pkg/policy/policy.go
+++ b/pkg/policy/policy.go
@@ -34,6 +34,10 @@ const (
 	SourcePolicyUri       = "github.com/slsa-framework/source-policies"
 	SourcePolicyRepoOwner = "slsa-framework"
 	SourcePolicyRepo      = "source-policies"
+
+	// DefaultPolicyPath is the policy path reported when a branch is
+	// evaluated using the default policy.
+	DefaultPolicyPath = "DEFAULT"
 )
 
 // Returns the policy for the branch or nil if the branch doesn't have one.
@@ -635,7 +639,7 @@ func (pe *PolicyEvaluator) EvaluateControl(ctx context.Context, repo *models.Rep
 	branchPolicy := rp.GetBranchPolicy(branch.Name)
 	if branchPolicy == nil {
 		branchPolicy = createDefaultBranchPolicy(branch)
-		policyPath = "DEFAULT"
+		policyPath = DefaultPolicyPath
 	}
 
 	if controlStatus.Time.Before(branchPolicy.GetSince().AsTime()) {
@@ -675,7 +679,7 @@ func (pe *PolicyEvaluator) EvaluateSourceProv(ctx context.Context, repo *models.
 	branchPolicy := rp.GetBranchPolicy(branch.Name)
 	if branchPolicy == nil {
 		branchPolicy = createDefaultBranchPolicy(branch)
-		policyPath = "DEFAULT"
+		policyPath = DefaultPolicyPath
 	}
 
 	verifiedLevels, shortfall, err := evaluateBranchControls(branchPolicy, rp.GetProtectedTag(), slsa.NewControlSetFromProvanenaceControls(provPred.GetControls()))
diff --git a/pkg/sourcetool/implementation.go b/pkg/sourcetool/implementation.go
index be395c4..89acec5 100644
--- a/pkg/sourcetool/implementation.go
+++ b/pkg/sourcetool/implementation.go
@@ -119,7 +119,7 @@ func (impl *defaultToolImplementation) CreatePolicyPR(a *auth.Authenticator, opt
 	}
 
 	policyRepo := &models.Repository{
-		Hostname:      "github.com",
+		Hostname:      githubHostname,
 		Path:          fmt.Sprintf("%s/%s", policyRepoOwner, policyRepoName),
 		DefaultBranch: "main",
 	}
@@ -163,7 +163,7 @@ func (impl *defaultToolImplementation) CheckForks(opts *options.Options) error {
 func (impl *defaultToolImplementation) CheckPolicyFork(opts *options.Options) error {
 	manager := repo.NewPullRequestManager()
 	if _, err := manager.CheckFork(&models.Repository{
-		Hostname: "github.com", Path: opts.PolicyRepo,
+		Hostname: githubHostname, Path: opts.PolicyRepo,
 	}, ""); err != nil {
 		return err
 	}
@@ -248,7 +248,7 @@ func (impl *defaultToolImplementation) GetPolicyStatus(
 
 	host := r.Hostname
 	if host == "" {
-		host = "github.com"
+		host = githubHostname
 	}
 	prNr, err := impl.SearchPullRequest(ctx, a, &models.Repository{
 		Hostname: host,
diff --git a/pkg/sourcetool/models/models.go b/pkg/sourcetool/models/models.go
index 06b9246..7e9422c 100644
--- a/pkg/sourcetool/models/models.go
+++ b/pkg/sourcetool/models/models.go
@@ -69,6 +69,12 @@ const (
 	CONFIG_TAG_RULES      ControlConfiguration = "CONFIG_TAG_RULES"
 )
 
+// Digest algorithm names used in attestation subjects
+const (
+	DigestTypeGitCommit = "gitCommit"
+	DigestTypeSha1      = "sha1"
+)
+
 type Commit struct {
 	SHA     string
 	Author  string
@@ -101,7 +107,7 @@ func (c *Commit) GetCommit() *Commit {
 func (c *Commit) ToResourceDescriptor() *attestation.ResourceDescriptor {
 	return &attestation.ResourceDescriptor{
 		Digest: map[string]string{
-			"sha1": c.SHA, "gitCommit": c.SHA,
+			DigestTypeSha1: c.SHA, DigestTypeGitCommit: c.SHA,
 		},
 	}
 }
diff --git a/pkg/sourcetool/tool.go b/pkg/sourcetool/tool.go
index e3a7aee..aace6e7 100644
--- a/pkg/sourcetool/tool.go
+++ b/pkg/sourcetool/tool.go
@@ -36,6 +36,9 @@ var ControlConfigurations = []models.ControlConfiguration{
 	models.CONFIG_POLICY, models.CONFIG_GEN_PROVENANCE, models.CONFIG_BRANCH_RULES, models.CONFIG_TAG_RULES,
 }
 
+// githubHostname is the hostname of the VCS system sourcetool supports (for now)
+const githubHostname = "github.com"
+
 // New initializes a new source tool instance.
 func New(funcs ...ConfigFn) (*Tool, error) {
 	t := &Tool{
@@ -194,7 +197,7 @@ func (t *Tool) FindPolicyPR(ctx context.Context, repo *models.Repository) (*mode
 	}
 
 	pr, err := t.impl.SearchPullRequest(ctx, t.Authenticator, &models.Repository{
-		Hostname: "github.com",
+		Hostname: githubHostname,
 		Path:     fmt.Sprintf("%s/%s", policyRepoOwner, policyRepoRepo),
 	}, fmt.Sprintf("Add %s SLSA Source policy file", repo.Path))
 	if err != nil {