Add shared report format flag

builtins.go

@@ -4,10 +4,10 @@ import (
 	"fmt"
 	"io"
 	"runtime/debug"
+	"text/template"
 
 	internalcobra "go.maximumdirect.net/commandkit/internal/cobra"
 	commandmeta "go.maximumdirect.net/commandkit/internal/commandmeta"
-	yaml "go.yaml.in/yaml/v4"
 )
 
 const commandKitModulePath = "go.maximumdirect.net/commandkit"
@@ -18,15 +18,16 @@ type helpInput struct {
 
 type versionInput struct {
 	Scope string
-	Format string
 }
 
 type versionDocument struct {
-	Name     string `yaml:"name"`
+	Name     string `json:"name"`
-	Version  string `yaml:"version"`
+	Version  string `json:"version"`
-	Revision string `yaml:"revision"`
+	Revision string `json:"revision"`
 }
 
+var versionTextTemplate = template.Must(ParseTextTemplate("version", "{{.Name}} {{.Version}}{{if .Revision}} ({{.Revision}}){{end}}\n", nil))
+
 func (a *App) builtinCommands() []Declaration {
 	help := captureCommand(CommandSpec[helpInput]{
 		Name:        "help",
@@ -39,14 +40,12 @@ func (a *App) builtinCommands() []Declaration {
 		return current.renderHelpTargets(input.Targets.Value)
 	})
 	scopeDefault := "app"
-	formatDefault := "text"
 	version := NewCommand(CommandSpec[versionInput]{
 		Name:        "version",
 		Summary:     "Show application or CommandKit version.",
 		Description: "Report identity and build metadata without loading application configuration.",
 		Flags: []Flag[versionInput]{
 			ValueFlag(FlagMeta{Name: "scope", Usage: "version subject", Completion: CompleteChoices(CompletionChoice{Value: "app"}, CompletionChoice{Value: "commandkit"})}, &scopeDefault, parseVersionScope, func(input *versionInput, value Supplied[string]) { input.Scope = value.Value }),
-			ValueFlag(FlagMeta{Name: "format", Usage: "output format", Completion: CompleteChoices(CompletionChoice{Value: "text"}, CompletionChoice{Value: "yaml"})}, &formatDefault, parseVersionFormat, func(input *versionInput, value Supplied[string]) { input.Format = value.Value }),
 		},
 		Run: func(invocation Invocation, input versionInput) Outcome {
 			identity := a.identity
@@ -56,7 +55,7 @@ func (a *App) builtinCommands() []Declaration {
 			if identity.Version == "" {
 				identity.Version = "dev"
 			}
-			return renderVersionOutcome(identity, input.Format, invocation.Reporter())
+			return renderVersionOutcome(identity, invocation.Reporter())
 		},
 	})
 	return []Declaration{help, version}
@@ -69,13 +68,6 @@ func parseVersionScope(value string) (string, error) {
 	return value, nil
 }
 
-func parseVersionFormat(value string) (string, error) {
-	if value != "text" && value != "yaml" {
-		return "", fmt.Errorf("format must be text or yaml, got %q", value)
-	}
-	return value, nil
-}
-
 func (a *App) renderHelpViewOutcomeWithSession(view commandmeta.HelpView, reporter *Reporter, session *internalcobra.Session) Outcome {
 	content, failure := session.RenderHelpView(view)
 	if failure != nil {
@@ -91,36 +83,14 @@ func (a *App) renderHelpViewOutcomeWithSession(view commandmeta.HelpView, report
 	return Success()
 }
 
-func renderVersionOutcome(identity Identity, format string, reporter *Reporter) Outcome {
+func renderVersionOutcome(identity Identity, reporter *Reporter) Outcome {
 	if identity.Version == "" {
 		identity.Version = "dev"
 	}
-	switch format {
+	_ = reporter.Report(Report{Value: versionDocument{Name: identity.Name, Version: identity.Version, Revision: identity.Revision}, TextTemplate: versionTextTemplate})
-	case "text":
-		line := identity.Name + " " + identity.Version
-		if identity.Revision != "" {
-			line += " (" + identity.Revision + ")"
-		}
-		_ = reporter.RenderOutput(func(w io.Writer) error {
-			_, err := io.WriteString(w, line+"\n")
-			return err
-		})
-	case "yaml":
-		_ = reporter.RenderOutput(func(w io.Writer) error {
-			return encodeYAML(w, versionDocument{Name: identity.Name, Version: identity.Version, Revision: identity.Revision})
-		})
-	default:
-		return Usage(fmt.Sprintf("unsupported version format %q", format))
-	}
 	return Success()
 }
 
-func encodeYAML(writer io.Writer, document any) error {
-	encoder := yaml.NewEncoder(writer)
-	encoder.SetIndent(2)
-	return encoder.Encode(document)
-}
-
 func readBuildInfo() *debug.BuildInfo {
 	info, ok := debug.ReadBuildInfo()
 	if !ok {

completion_query_test.go

@@ -43,6 +43,7 @@ func TestCompletionQueryDispatch(t *testing.T) {
 		{"alias value", []string{"__complete", "shortcut", "--colour=bl"}, "blue\tcool color\n", false},
 		{"quiet is data", []string{"__complete", "run", "--quiet", "--color=bl"}, "blue\tcool color\n", false},
 		{"debug is data", []string{"__complete", "run", "--debug", "--color=bl"}, "blue\tcool color\n", false},
+		{"format value", []string{"__complete", "run", "--format", "j"}, "json\n", false},
 		{"short attached choice", []string{"__complete", "run", "-cfoo=ba"}, "foo=bar\n", false},
 		{"unknown route", []string{"__complete", "missing", ""}, emptyReply, true},
 	} {

completion_test.go

@@ -54,7 +54,7 @@ func TestCompletionHintsFollowCapturedBindings(t *testing.T) {
 		t.Fatalf("no completion: %#v", got)
 	}
 	for _, flag := range append(commandmeta.ReportingFlags(), commandmeta.HelpFlag()) {
-		if !reflect.DeepEqual(flag.Completion.Choices, []commandmeta.CompletionChoice{{Value: "true"}, {Value: "false"}}) {
+		if flag.Boolean && !reflect.DeepEqual(flag.Completion.Choices, []commandmeta.CompletionChoice{{Value: "true"}, {Value: "false"}}) {
 			t.Fatalf("reporting flag choices: %#v", flag)
 		}
 	}

declaration_external_test.go

@@ -18,15 +18,15 @@ func TestPublicInstallationAcceptsMixedDeclarations(t *testing.T) {
 		Name:    "show",
 		Summary: "Show a value.",
 		Flags: []commandkit.Flag[struct{}]{
-			commandkit.ValueFlag(commandkit.FlagMeta{Name: "format"}, (*string)(nil), func(value string) (string, error) { return value, nil }, func(*struct{}, commandkit.Supplied[string]) {}),
+			commandkit.ValueFlag(commandkit.FlagMeta{Name: "style"}, (*string)(nil), func(value string) (string, error) { return value, nil }, func(*struct{}, commandkit.Supplied[string]) {}),
 		},
 		Run: func(commandkit.Invocation, struct{}) commandkit.Outcome { return commandkit.Success() },
 	})
 	declarations := []commandkit.Declaration{
 		command,
 		commandkit.Alias("inspect", "show"),
-		commandkit.FlagAlias("--fmt", "--format"),
+		commandkit.FlagAlias("--fmt", "--style"),
-		commandkit.FlagAliasFor("show", "-f", "--format"),
+		commandkit.FlagAliasFor("show", "-f", "--style"),
 	}
 	app, err := commandkit.New(commandkit.Identity{Name: "Example"}, declarations...)
 	if err != nil {
@@ -84,7 +84,7 @@ func TestPublicAliasesPreserveCommandsAcrossDeclarationOrders(t *testing.T) {
 					func(value string) (string, error) { optionalParses++; return value, nil },
 					func(target *showInput, value commandkit.Supplied[string]) { target.profile = value },
 				)},
-				Flags: []commandkit.Flag[showInput]{commandkit.ValueFlag(commandkit.FlagMeta{Name: "format"}, (*string)(nil),
+				Flags: []commandkit.Flag[showInput]{commandkit.ValueFlag(commandkit.FlagMeta{Name: "style"}, (*string)(nil),
 					func(value string) (string, error) { return value, nil },
 					func(target *showInput, value commandkit.Supplied[string]) { target.format = value },
 				)},
@@ -99,7 +99,7 @@ func TestPublicAliasesPreserveCommandsAcrossDeclarationOrders(t *testing.T) {
 				commandkit.Alias("r full", "inspect"),
 				commandkit.Alias("inspect-shortcut", "inspect"),
 				commandkit.Alias("i", "inspect-shortcut"),
-				commandkit.FlagAlias("--fmt", "--format"),
+				commandkit.FlagAlias("--fmt", "--style"),
 			}
 			declarations := append([]commandkit.Declaration(nil), commands...)
 			if test.rulesFirst {
@@ -154,7 +154,7 @@ func TestPublicRootGroupRegistrationAndFailedBatchRecovery(t *testing.T) {
 	var formats []string
 	show := commandkit.NewCommand(commandkit.CommandSpec[showInput]{
 		Name: "show",
-		Flags: []commandkit.Flag[showInput]{commandkit.ValueFlag(commandkit.FlagMeta{Name: "format"}, (*string)(nil),
+		Flags: []commandkit.Flag[showInput]{commandkit.ValueFlag(commandkit.FlagMeta{Name: "style"}, (*string)(nil),
 			func(value string) (string, error) { formatParses++; return value, nil },
 			func(target *showInput, value commandkit.Supplied[string]) { target.format = value },
 		)},
@@ -181,7 +181,7 @@ func TestPublicRootGroupRegistrationAndFailedBatchRecovery(t *testing.T) {
 	if err := app.Register(family,
 		commandkit.Alias("cfg-show", "config show"),
 		commandkit.Alias("cs", "cfg-show"),
-		commandkit.FlagAlias("--fmt", "--format"),
+		commandkit.FlagAlias("--fmt", "--style"),
 	); err != nil {
 		t.Fatal(err)
 	}

docs/cli.md

@@ -46,7 +46,7 @@ The supported flags are:
 | Flag | Values | Default | Meaning |
 | --- | --- | --- | --- |
 | `--scope` | `app`, `commandkit` | `app` | Select the caller's application identity or the embedded CommandKit module identity. |
-| `--format` | `text`, `yaml` | `text` | Select the output format. |
+| `--format` | `text`, `yaml`, `json` | automatic | Select the output format; automatic uses text for version. |
 
 Text output is `NAME VERSION`, followed by ` (REVISION)` when the selected
 identity has a revision. An empty application version is displayed as `dev`;
@@ -58,7 +58,7 @@ versionless replacement, an untagged module, or missing build information
 displays `dev`. The CommandKit identity name is `CommandKit`; dependency build
 metadata does not supply a revision.
 
-YAML output uses these explicit fields, including an empty revision:
+YAML and JSON output use these fields, including an empty revision:
 
 ```yaml
 name: ExampleApp
@@ -111,6 +111,14 @@ caller passes result and diagnostic writers to `App.Execute`; substantive
 results go to `Streams.Out`, and categorized messages, terminal explanations,
 and usage guidance go to `Streams.Err`.
 
+The shared `--format` flag selects `text`, `yaml`, or `json` for reports
+submitted through the core reporter. When omitted, a report's text template
+selects text; otherwise scalar values and nonempty string lists use text, while
+structured values and empty collections use YAML. Explicit text without a
+template uses YAML for structured values. Invalid or empty format values are
+usage errors. Raw output, help, completion, and diagnostics are not encoded as
+reports.
+
 ### Modes and visibility
 
 Each invocation starts in ordinary mode. `--quiet`, `--verbose`, and `--debug`
@@ -154,9 +162,9 @@ example version --quiet
 Reporting flags do not go before or between command-path components. Tokens
 consumed as values and tokens after `--` retain their normal meaning.
 
-The reserved long spellings are `--quiet`, `--verbose`, `--debug`, and
+The reserved long spellings are `--quiet`, `--verbose`, `--debug`,
-`--progress`; application declarations cannot reuse them. There are no built-in
+`--progress`, and `--format`; application declarations cannot reuse them. There
-short spellings. Applications may define aliases such as `-q → --quiet`,
+are no built-in short spellings. Applications may define aliases such as `-q → --quiet`,
 `-v → --verbose`, and `-d → --debug`; canonical and aliased occurrences share
 the same ordering. Thus `example export --verbose -q` selects quiet mode.
 

docs/consumers/guide.md

@@ -135,7 +135,8 @@ installation alongside aliases and integration commands.
 ## Invocation reporting
 
 `Invocation.Reporter()` supplies the reporter for the current handler. Use
-`Output()` or `RenderOutput()` for substantive results; use `Warn`, `Info`,
+`Report()` for formatted substantive values and optional text templates;
+use `Output()` or `RenderOutput()` for deliberate raw output. Use `Warn`, `Info`,
 `Progress`, and `Debug` for categorized messages. Queue a summary with
 `AtEnd().Info` when it belongs after the handler returns. The
 [CLI reference](../cli.md#reporting) owns flag grammar, visibility, prefixes,

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # Shared reporting and PromptKit v0.20.0 implementation plan
 
-Status: implementation in progress; Stages 1–3 complete.
+Status: implementation in progress; Stages 1–4 complete.
 
 ## Scope, authority, and execution
 
@@ -160,6 +160,11 @@ boundary in GoDoc.
 
 ## Stage 4: Universal format input, core version, and a core consumer
 
+**Complete.** Core format selection, version reporting, and a maintained core
+consumer use the shared report path. Focused parser, routing, completion, and
+reporting tests and the root workspace suite (`GOTOOLCHAIN=local go test ./...`
+with Go 1.27.0) passed. Integration migrations remain in later stages.
+
 Extend neutral core flag metadata and parser selection in
 [metadata.go](../../internal/commandmeta/metadata.go),
 [parser.go](../../parser.go), and the internal Cobra adapter. Add core-owned

examples/core/main.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"os"
 	"strconv"
+	"text/template"
 
 	commandkit "go.maximumdirect.net/commandkit"
 )
@@ -20,6 +21,15 @@ type reportInput struct {
 	Scenario string
 }
 
+type greetingReport struct {
+	Count     string `json:"count"`
+	Tags      string `json:"tags"`
+	Entered   string `json:"entered"`
+	Canonical string `json:"canonical"`
+}
+
+var greetingTemplate = template.Must(commandkit.ParseTextTemplate("greeting", "Hello; count={{.Count}}; tags={{.Tags}}; entered={{printf \"%q\" .Entered}}; canonical={{printf \"%q\" .Canonical}}\n", nil))
+
 var (
 	errRecoveredFixture = errors.New("a local read failed and was recovered")
 	errWarningFixture   = errors.New("a local warning has a cause")
@@ -50,10 +60,7 @@ func newApp() (*commandkit.App, error) {
 			if input.Tags.Set {
 				tags = fmt.Sprintf("explicit %v", input.Tags.Value)
 			}
-			_ = reporter.RenderOutput(func(writer io.Writer) error {
+			_ = reporter.Report(commandkit.Report{Value: greetingReport{Count: count, Tags: tags, Entered: invocation.EnteredPath(), Canonical: invocation.CanonicalPath()}, TextTemplate: greetingTemplate})
-				_, err := fmt.Fprintf(writer, "Hello; count=%s; tags=%s; entered=%q; canonical=%q\n", count, tags, invocation.EnteredPath(), invocation.CanonicalPath())
-				return err
-			})
 			return commandkit.Success()
 		},
 	})

execute_external_test.go

@@ -475,10 +475,15 @@ func TestVersionCommandFormatsApplicationAndCommandKitIdentity(t *testing.T) {
 	}
 	out.Reset()
 	yamlOutcome := app.Execute(context.Background(), []string{"version", "--format=yaml"}, commandkit.Streams{Out: &out, Err: &diagnostic})
-	if yamlOutcome.Kind != commandkit.OutcomeSuccess || out.String() != "name: ExampleApp\nversion: dev\nrevision: abc123\n" {
+	if yamlOutcome.Kind != commandkit.OutcomeSuccess || !strings.Contains(out.String(), "name: ExampleApp\n") || !strings.Contains(out.String(), "version: dev\n") || !strings.Contains(out.String(), "revision: abc123\n") {
 		t.Fatalf("YAML version = %#v, output %q", yamlOutcome, out.String())
 	}
 	out.Reset()
+	jsonOutcome := app.Execute(context.Background(), []string{"version", "--format=json"}, commandkit.Streams{Out: &out, Err: &diagnostic})
+	if jsonOutcome.Kind != commandkit.OutcomeSuccess || !strings.Contains(out.String(), `"revision": "abc123"`) {
+		t.Fatalf("JSON version = %#v, output %q", jsonOutcome, out.String())
+	}
+	out.Reset()
 	component := app.Execute(context.Background(), []string{"version", "--scope=commandkit"}, commandkit.Streams{Out: &out, Err: &diagnostic})
 	if component.Kind != commandkit.OutcomeSuccess || !strings.HasPrefix(out.String(), "CommandKit ") || !strings.HasSuffix(out.String(), "\n") {
 		t.Fatalf("CommandKit version = %#v, output %q", component, out.String())

flag_aliases_test.go

@@ -23,8 +23,8 @@ func stringFlag(name, short string) Flag[struct{}] {
 }
 
 func TestFlagAliasChainsUseScopedOverridesAndCanonicalEndpoints(t *testing.T) {
-	inspect := flagAliasCommand("inspect", stringFlag("color", "c"), stringFlag("format", "f"))
+	inspect := flagAliasCommand("inspect", stringFlag("color", "c"), stringFlag("style", "f"))
-	show := flagAliasCommand("show", stringFlag("color", "c"), stringFlag("format", "f"))
+	show := flagAliasCommand("show", stringFlag("color", "c"), stringFlag("style", "f"))
 	group := Group("Tools", "tools", show)
 	app, err := New(Identity{Name: "Example"},
 		inspect,
@@ -35,8 +35,8 @@ func TestFlagAliasChainsUseScopedOverridesAndCanonicalEndpoints(t *testing.T) {
 		FlagAlias("-x", "--color"),
 		FlagAlias("--tint", "-c"),
 		FlagAliasFor("Tools", "--group-help", "--help"),
-		FlagAliasFor("inspect", "--hue", "--format"),
+		FlagAliasFor("inspect", "--hue", "--style"),
-		FlagAliasFor("inspect", "--local", "--format"),
+		FlagAliasFor("inspect", "--local", "--style"),
 	)
 	if err != nil {
 		t.Fatal(err)
@@ -44,11 +44,11 @@ func TestFlagAliasChainsUseScopedOverridesAndCanonicalEndpoints(t *testing.T) {
 
 	inspectAliases := app.flagAliases[commandpath.Path{"inspect"}.Key()].bySpelling
 	for source, target := range map[string]string{
-		"--colour": "--format",
+		"--colour": "--style",
-		"--hue":    "--format",
+		"--hue":    "--style",
 		"-x":       "--color",
 		"--tint":   "-c",
-		"--local":  "--format",
+		"--local":  "--style",
 	} {
 		alias, ok := inspectAliases[flagSpellingKey(capturedSpelling(source))]
 		if !ok || alias.target.token() != target {
@@ -126,7 +126,7 @@ func TestFlagAliasDiscoveryContextsUseGlobalReportingAliases(t *testing.T) {
 }
 
 func TestReportingFlagsAreReservedAndAcceptApplicationShortAliases(t *testing.T) {
-	for _, name := range []string{"quiet", "verbose", "debug", "progress"} {
+	for _, name := range []string{"quiet", "verbose", "debug", "progress", "format"} {
 		command := flagAliasCommand("reserved", stringFlag(name, ""))
 		if len(command.record.issues) == 0 {
 			t.Errorf("capturing --%s did not retain a declaration error", name)
@@ -154,7 +154,7 @@ func TestReportingFlagsAreReservedAndAcceptApplicationShortAliases(t *testing.T)
 }
 
 func TestReportingFlagSpellingsConflictWithAliasSources(t *testing.T) {
-	for _, name := range []string{"quiet", "verbose", "debug", "progress"} {
+	for _, name := range []string{"quiet", "verbose", "debug", "progress", "format"} {
 		if _, err := New(Identity{Name: "Example"}, FlagAlias("--"+name, "--help")); err == nil || !strings.Contains(err.Error(), "conflicts with a canonical spelling") {
 			t.Errorf("alias source --%s returned %v, want a canonical spelling collision", name, err)
 		}
@@ -166,7 +166,7 @@ func TestReportingFlagSpellingsConflictWithAliasSources(t *testing.T) {
 
 func TestRoutingSnapshotCarriesReportingMetadataOutsideConsumerBindings(t *testing.T) {
 	app, err := New(Identity{Name: "Example"},
-		flagAliasCommand("run", stringFlag("format", "f")),
+		flagAliasCommand("run", stringFlag("style", "f")),
 		Group("tools", "", flagAliasCommand("show")),
 	)
 	if err != nil {
@@ -174,7 +174,7 @@ func TestRoutingSnapshotCarriesReportingMetadataOutsideConsumerBindings(t *testi
 	}
 	var check func(*commandmeta.Command)
 	check = func(node *commandmeta.Command) {
-		if len(node.CoreFlags) != 4 {
+		if len(node.CoreFlags) != 5 {
 			t.Errorf("%s core reporting flags = %#v", node.Name, node.CoreFlags)
 		}
 		for _, flag := range node.Flags {
@@ -190,15 +190,15 @@ func TestRoutingSnapshotCarriesReportingMetadataOutsideConsumerBindings(t *testi
 }
 
 func TestFlagAliasDuplicatesAndScopesAreDeterministic(t *testing.T) {
-	command := flagAliasCommand("inspect", stringFlag("color", "c"), stringFlag("format", "f"))
+	command := flagAliasCommand("inspect", stringFlag("color", "c"), stringFlag("style", "f"))
 	duplicate := FlagAlias("--colour", "--color")
 	app, err := New(Identity{Name: "Example"}, command, flagAliasCommand("plain", stringFlag("color", "c")), duplicate, FlagAlias("--colour", "--color"),
-		FlagAliasFor("inspect", "--colour", "--format"))
+		FlagAliasFor("inspect", "--colour", "--style"))
 	if err != nil {
 		t.Fatalf("identical duplicates and scoped override were rejected: %v", err)
 	}
-	if got := app.flagAliases[commandpath.Path{"inspect"}.Key()].bySpelling[flagSpellingKey(capturedFlagSpelling{name: "colour"})].target.token(); got != "--format" {
+	if got := app.flagAliases[commandpath.Path{"inspect"}.Key()].bySpelling[flagSpellingKey(capturedFlagSpelling{name: "colour"})].target.token(); got != "--style" {
-		t.Fatalf("scoped alias target = %s, want --format", got)
+		t.Fatalf("scoped alias target = %s, want --style", got)
 	}
 	if got := app.flagAliases[commandpath.Path{"plain"}.Key()].bySpelling[flagSpellingKey(capturedFlagSpelling{name: "colour"})].target.token(); got != "--color" {
 		t.Fatalf("effective global alias target = %s, want --color", got)
@@ -207,11 +207,11 @@ func TestFlagAliasDuplicatesAndScopesAreDeterministic(t *testing.T) {
 	for name, rules := range map[string][]RoutingRule{
 		"competing global targets": {
 			FlagAlias("--colour", "--color"),
-			FlagAlias("--colour", "--format"),
+			FlagAlias("--colour", "--style"),
 		},
 		"competing scoped targets": {
 			FlagAliasFor("inspect", "--colour", "--color"),
-			FlagAliasFor("inspect", "--colour", "--format"),
+			FlagAliasFor("inspect", "--colour", "--style"),
 		},
 		"unknown scope":              {FlagAliasFor("missing", "--colour", "--color")},
 		"missing scoped destination": {FlagAliasFor("inspect", "--colour", "--missing")},

format_flag_test.go

@@ -0,0 +1,82 @@
+package commandkit
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"reflect"
+	"strings"
+	"testing"
+
+	commandmeta "go.maximumdirect.net/commandkit/internal/commandmeta"
+)
+
+func TestSharedFormatFlag(t *testing.T) {
+	factories, runs := 0, 0
+	command := NewCommand(CommandSpec[struct{}]{Name: "run", NewInput: func() struct{} { factories++; return struct{}{} }, Run: func(inv Invocation, _ struct{}) Outcome {
+		runs++
+		_ = inv.Reporter().Report(Report{Value: map[string]any{"answer": 42}})
+		return Success()
+	}})
+	app, err := New(Identity{Name: "Example", Version: "1"}, command, FlagAlias("--fmt", "--format"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, tc := range []struct {
+		args     []string
+		expected string
+	}{
+		{[]string{"run", "--format", "text"}, "yaml"},
+		{[]string{"run", "--format=yaml"}, "yaml"},
+		{[]string{"run", "--fmt=json"}, "json"},
+		{[]string{"run", "--format=yaml", "--fmt", "json"}, "json"},
+		{[]string{"run"}, "yaml"},
+	} {
+		var out bytes.Buffer
+		got := app.Execute(context.Background(), tc.args, Streams{Out: &out})
+		if got.Status != 0 {
+			t.Fatalf("%v: %#v", tc.args, got)
+		}
+		var value any
+		if tc.expected == "json" {
+			dec := json.NewDecoder(&out)
+			dec.UseNumber()
+			err = dec.Decode(&value)
+		} else {
+			value, err = DecodeYAMLReport(&out)
+		}
+		if err != nil || !reflect.DeepEqual(value, map[string]any{"answer": json.Number("42")}) {
+			t.Fatalf("%v: %#v %v", tc.args, value, err)
+		}
+	}
+	beforeFactories, beforeRuns := factories, runs
+	for _, args := range [][]string{{"run", "--format="}, {"run", "--fmt=xml"}, {"run", "--format=bad", "--format=json"}, {"run", "--format", "--quiet"}} {
+		var diagnostics bytes.Buffer
+		got := app.Execute(context.Background(), args, Streams{Err: &diagnostics})
+		if got.Kind != OutcomeUsage || !strings.Contains(diagnostics.String(), "format") {
+			t.Fatalf("%v: %#v %q", args, got, &diagnostics)
+		}
+	}
+	if factories != beforeFactories || runs != beforeRuns {
+		t.Fatalf("invalid formats ran domain code: factories %d, runs %d", factories, runs)
+	}
+	var help bytes.Buffer
+	got := app.Execute(context.Background(), []string{"run", "--help"}, Streams{Out: &help})
+	if got.Status != 0 || !strings.Contains(help.String(), "--format") || factories != beforeFactories || runs != beforeRuns {
+		t.Fatalf("help: %#v, %q", got, &help)
+	}
+}
+
+func TestSharedFormatParseOrderAndTerminator(t *testing.T) {
+	app, err := New(Identity{Name: "Example"}, flagAliasCommand("run", stringFlag("message", "")), FlagAlias("--fmt", "--format"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	result := parseReportingArgs(app, []string{"run", "--verbose", "--fmt", "json", "--quiet", "--message=--format", "--", "--format=yaml"})
+	if result.Failure != nil || result.Reporting.Format != "json" || result.Reporting.Mode != commandmeta.ReportingModeQuiet || !reflect.DeepEqual(result.Operands, []string{"--format=yaml"}) {
+		t.Fatalf("%#v", result)
+	}
+	if result.FlagOccurrences[1].Spelling != "--fmt" || result.FlagOccurrences[1].RawValue != "json" {
+		t.Fatalf("%#v", result.FlagOccurrences)
+	}
+}

internal/cobra/parse_test.go

@@ -80,10 +80,10 @@ func TestParseInterspersedOperandsBooleanFlagsAndTerminator(t *testing.T) {
 func TestReportingFlagsParseWithoutChangingConsumerFlagIndexes(t *testing.T) {
 	tree := &Command{Name: "app", CoreFlags: commandmeta.ReportingFlags(), Children: []*Command{
 		{Name: "config", CoreFlags: commandmeta.ReportingFlags(), Children: []*Command{
-			{Name: "show", Runnable: true, CoreFlags: commandmeta.ReportingFlags(), Flags: []Flag{{Name: "format"}}},
+			{Name: "show", Runnable: true, CoreFlags: commandmeta.ReportingFlags(), Flags: []Flag{{Name: "style"}}},
 		}},
 	}}
-	result := Parse(tree, []string{"config", "show", "--quiet", "-v", "--format=yaml"}, ParseOptions{
+	result := Parse(tree, []string{"config", "show", "--quiet", "-v", "--style=yaml"}, ParseOptions{
 		FlagAliases: []commandmeta.FlagAlias{{Source: "-v", Target: "--verbose"}},
 	})
 	if result.Failure != nil {
@@ -92,7 +92,7 @@ func TestReportingFlagsParseWithoutChangingConsumerFlagIndexes(t *testing.T) {
 	if !reflect.DeepEqual(result.FlagValues, [][]string{{"yaml"}}) {
 		t.Fatalf("consumer binding values = %#v", result.FlagValues)
 	}
-	if !reflect.DeepEqual(result.FlagSpellings, [][]string{{"--format"}}) {
+	if !reflect.DeepEqual(result.FlagSpellings, [][]string{{"--style"}}) {
 		t.Fatalf("consumer binding spellings = %#v", result.FlagSpellings)
 	}
 }

internal/commandmeta/metadata.go

@@ -79,6 +79,7 @@ var reportingFlags = [...]Flag{
 	{Name: "verbose", Usage: "show warning and informational messages", Default: "false", Boolean: true},
 	{Name: "debug", Usage: "show debugging messages", Default: "false", Boolean: true},
 	{Name: "progress", Usage: "show progress messages", Default: "false", Boolean: true},
+	{Name: "format", Usage: "report format: text, yaml, or json", Completion: CompletionHint{Kind: CompletionChoices, Choices: []CompletionChoice{{Value: "text"}, {Value: "yaml"}, {Value: "json"}}}},
 }
 
 // BooleanCompletion returns the ordinary explicit boolean suggestions.
@@ -95,7 +96,11 @@ func HelpFlag() Flag {
 func ReportingFlags() []Flag {
 	flags := append([]Flag(nil), reportingFlags[:]...)
 	for index := range flags {
+		if flags[index].Boolean {
 			flags[index].Completion = BooleanCompletion()
+		} else {
+			flags[index].Completion.Choices = append([]CompletionChoice(nil), flags[index].Completion.Choices...)
+		}
 	}
 	return flags
 }
@@ -160,6 +165,7 @@ type ReportingSelection struct {
 	Mode        ReportingMode
 	Progress    bool
 	ProgressSet bool
+	Format      string
 }
 
 // Result contains the selected command and raw input collected by the adapter.

internal/commandmeta/metadata_test.go

@@ -5,7 +5,7 @@ import "testing"
 func TestReportingFlagsAreBooleanAndReturnedIndependently(t *testing.T) {
 	flags := ReportingFlags()
 	want := []string{"quiet", "verbose", "debug", "progress"}
-	if len(flags) != len(want) {
+	if len(flags) != len(want)+1 {
 		t.Fatalf("reporting flags = %#v", flags)
 	}
 	for index, name := range want {
@@ -16,6 +16,13 @@ func TestReportingFlagsAreBooleanAndReturnedIndependently(t *testing.T) {
 			t.Errorf("%q is not recognized as a reporting flag", name)
 		}
 	}
+	if flags[4].Name != "format" || flags[4].Boolean || !IsReportingFlag("format") {
+		t.Fatalf("format metadata = %#v", flags[4])
+	}
+	flags[4].Completion.Choices[0].Value = "changed"
+	if ReportingFlags()[4].Completion.Choices[0].Value != "text" {
+		t.Fatal("caller mutation changed format choices")
+	}
 	flags[0].Name = "changed"
 	if ReportingFlags()[0].Name != "quiet" {
 		t.Fatal("caller mutation changed shared reporting metadata")

parser.go

@@ -24,6 +24,18 @@ func reduceReportingOccurrences(result commandmeta.Result) commandmeta.Result {
 		if !commandmeta.IsReportingFlag(occurrence.Name) {
 			continue
 		}
+		if occurrence.Name == "format" {
+			switch Format(occurrence.RawValue) {
+			case FormatText, FormatYAML, FormatJSON:
+				selection.Format = occurrence.RawValue
+			default:
+				result.FlagOccurrences = result.FlagOccurrences[:index+1]
+				result.Reporting = selection
+				result.Failure = &commandmeta.Failure{Message: fmt.Sprintf("invalid format %q for %s (expected text, yaml, or json)", occurrence.RawValue, occurrence.Spelling), Usage: true}
+				return result
+			}
+			continue
+		}
 		enabled, err := strconv.ParseBool(occurrence.RawValue)
 		if err != nil {
 			result.FlagOccurrences = result.FlagOccurrences[:index+1]

reporter.go

@@ -134,6 +134,7 @@ func (r *Reporter) applySelection(selection commandmeta.ReportingSelection) {
 	}
 	state.progress = selection.Progress
 	state.progressSet = selection.ProgressSet
+	state.format = Format(selection.Format)
 }
 
 // Output returns a managed writer for substantive command results. Writes are

route_operands_test.go

@@ -27,7 +27,7 @@ func TestRunnableParentKeepsNonCommandTokensAsOperands(t *testing.T) {
 		Arguments: []Argument[input]{RepeatArgument(ArgumentMeta{Name: "ARG"}, 0, -1,
 			func(value string) (string, error) { return value, nil },
 			func(target *input, value Supplied[[]string]) { target.words = value.Value })},
-		Flags: []Flag[input]{ValueFlag(FlagMeta{Name: "format", Short: "f"}, (*string)(nil),
+		Flags: []Flag[input]{ValueFlag(FlagMeta{Name: "style", Short: "f"}, (*string)(nil),
 			func(value string) (string, error) { return value, nil },
 			func(target *input, value Supplied[string]) { target.format = value })},
 		Run: func(inv Invocation, value input) Outcome {
@@ -36,7 +36,7 @@ func TestRunnableParentKeepsNonCommandTokensAsOperands(t *testing.T) {
 			return Success()
 		},
 	})
-	app, err := New(Identity{Name: "Demo"}, parent, Alias("r", "run"), FlagAliasFor("run", "--fmt", "--format"))
+	app, err := New(Identity{Name: "Demo"}, parent, Alias("r", "run"), FlagAliasFor("run", "--fmt", "--style"))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -56,7 +56,7 @@ func TestRunnableParentKeepsNonCommandTokensAsOperands(t *testing.T) {
 				}
 				outcome = app.Execute(context.Background(), append(args, "--help"), Streams{Out: &output, Err: &diagnostics})
 				if outcome.Kind != OutcomeSuccess || built != beforeBuilt+1 || parentRuns != beforeRuns+1 ||
-					!strings.Contains(output.String(), "Demo "+spelling+" [ARG...]") || !strings.Contains(output.String(), "--fmt → --format") {
+					!strings.Contains(output.String(), "Demo "+spelling+" [ARG...]") || !strings.Contains(output.String(), "--fmt → --style") {
 					t.Fatalf("parent help = %#v, output %q, diagnostics %q", outcome, output.String(), diagnostics.String())
 				}
 				outcome = app.Execute(context.Background(), []string{spelling, "--", operand, "child", "--fmt=yaml"}, Streams{Out: io.Discard, Err: &diagnostics})

route_test.go

@@ -67,14 +67,14 @@ func TestParserFailuresRetainAliasUsageAndFlagSpellings(t *testing.T) {
 	command := NewCommand(CommandSpec[struct{}]{
 		Name:     "inspect",
 		NewInput: func() struct{} { built++; return struct{}{} },
-		Flags: []Flag[struct{}]{ValueFlag(FlagMeta{Name: "format"}, (*string)(nil),
+		Flags: []Flag[struct{}]{ValueFlag(FlagMeta{Name: "style"}, (*string)(nil),
 			func(value string) (string, error) { return value, nil },
 			func(*struct{}, Supplied[string]) {})},
 		Run: func(Invocation, struct{}) Outcome { t.Fatal("invalid input executed"); return Success() },
 	})
 	app, err := New(Identity{Name: "Demo"}, command, Alias("i", "inspect"),
-		FlagAliasFor("inspect", "--fmt", "--format"),
+		FlagAliasFor("inspect", "--fmt", "--style"),
-		FlagAliasFor("inspect", "-F", "--format"), FlagAlias("--hlep", "--help"))
+		FlagAliasFor("inspect", "-F", "--style"), FlagAlias("--hlep", "--help"))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -111,7 +111,7 @@ func TestCommandContextSurvivesIncompleteAndInvalidOperandCounts(t *testing.T) {
 			usage bool
 		}{
 			{name: "interspersed alias", args: []string{"first", "--fmt=yaml", "second"}},
-			{name: "interspersed canonical flag", args: []string{"first", "--format=yaml", "second"}},
+			{name: "interspersed canonical flag", args: []string{"first", "--style=yaml", "second"}},
 			{name: "partial help", args: []string{"first", "--help"}, help: true},
 			{name: "partial help with flag alias", args: []string{"first", "--fmt=yaml", "--help"}, help: true},
 			{name: "excess operands", args: []string{"first", "second", "third", "--fmt=yaml"}, usage: true},
@@ -125,7 +125,7 @@ func TestCommandContextSurvivesIncompleteAndInvalidOperandCounts(t *testing.T) {
 				built, ran := 0, false
 				command := NewCommand(CommandSpec[input]{
 					Name: "run", NewInput: func() input { built++; return input{} },
-					Flags: []Flag[input]{ValueFlag(FlagMeta{Name: "format"}, (*string)(nil),
+					Flags: []Flag[input]{ValueFlag(FlagMeta{Name: "style"}, (*string)(nil),
 						func(value string) (string, error) { return value, nil },
 						func(target *input, value Supplied[string]) { target.format = value })},
 					Arguments: []Argument[input]{RepeatArgument(ArgumentMeta{Name: "ARG"}, 2, 2,
@@ -142,7 +142,7 @@ func TestCommandContextSurvivesIncompleteAndInvalidOperandCounts(t *testing.T) {
 						return Success()
 					},
 				})
-				app, err := New(Identity{Name: "Demo"}, command, Alias("r", "run"), FlagAliasFor("run", "--fmt", "--format"))
+				app, err := New(Identity{Name: "Demo"}, command, Alias("r", "run"), FlagAliasFor("run", "--fmt", "--style"))
 				if err != nil {
 					t.Fatal(err)
 				}
@@ -155,7 +155,7 @@ func TestCommandContextSurvivesIncompleteAndInvalidOperandCounts(t *testing.T) {
 				} else if outcome.Kind != OutcomeSuccess {
 					t.Fatalf("outcome = %#v, diagnostics %q", outcome, diagnostics.String())
 				}
-				if test.help && (!strings.Contains(output.String(), "Demo "+spelling+" ARG") || !strings.Contains(output.String(), "--fmt → --format")) {
+				if test.help && (!strings.Contains(output.String(), "Demo "+spelling+" ARG") || !strings.Contains(output.String(), "--fmt → --style")) {
 					t.Errorf("command help = %q", output.String())
 				}
 				if test.help || test.usage {
@@ -229,13 +229,13 @@ func TestDiscoveryHelpComposesGroupShortcutsAndOverrides(t *testing.T) {
 			initialized := false
 			inspect := NewCommand(CommandSpec[struct{}]{
 				Name: "inspect", NewInput: func() struct{} { initialized = true; return struct{}{} },
-				Flags: []Flag[struct{}]{ValueFlag(FlagMeta{Name: "format"}, (*string)(nil),
+				Flags: []Flag[struct{}]{ValueFlag(FlagMeta{Name: "style"}, (*string)(nil),
 					func(value string) (string, error) { return value, nil }, func(*struct{}, Supplied[string]) {})},
 				Run: func(Invocation, struct{}) Outcome { return Success() },
 			})
 			declarations := []Declaration{Group("box", "Box"), inspect, simpleRunnable("alternate"),
 				Alias("pk", "box"), Alias("box admin pick", "inspect"), Alias("box admin other", "inspect"),
-				FlagAlias("--hlep", "--help"), FlagAliasFor("inspect", "--fmt", "--format")}
+				FlagAlias("--hlep", "--help"), FlagAliasFor("inspect", "--fmt", "--style")}
 			wantPick := "pick → inspect"
 			if override {
 				declarations = append(declarations, Alias("pk admin pick", "alternate"), Alias("pk admin nested choose", "inspect"))
@@ -308,7 +308,7 @@ func TestHelpDiscoversRoutesThroughIntermediateAliases(t *testing.T) {
 			makeCommand := func(name string) Command {
 				return NewCommand(CommandSpec[struct{}]{
 					Name: name, NewInput: func() struct{} { built++; return struct{}{} },
-					Flags: []Flag[struct{}]{ValueFlag(FlagMeta{Name: "format"}, (*string)(nil),
+					Flags: []Flag[struct{}]{ValueFlag(FlagMeta{Name: "style"}, (*string)(nil),
 						func(value string) (string, error) { return value, nil }, func(*struct{}, Supplied[string]) {})},
 					Run: func(inv Invocation, _ struct{}) Outcome {
 						runs++
@@ -327,7 +327,7 @@ func TestHelpDiscoversRoutesThroughIntermediateAliases(t *testing.T) {
 			}
 			declarations := []Declaration{group, makeCommand("inspect"), makeCommand("alternate"),
 				Alias("p", "q"), Alias("q", target), Alias(middle+" pick", "inspect"), Alias(middle+" other", "inspect"),
-				FlagAlias("--hlep", "--help"), FlagAliasFor("inspect", "--fmt", "--format")}
+				FlagAlias("--hlep", "--help"), FlagAliasFor("inspect", "--fmt", "--style")}
 			wantTarget := "inspect"
 			if test.override {
 				declarations = append(declarations, Alias(prefix+" pick", "alternate"))
@@ -352,7 +352,7 @@ func TestHelpDiscoversRoutesThroughIntermediateAliases(t *testing.T) {
 						t.Errorf("help %q omits %q", output.String(), fragment)
 					}
 				}
-				if strings.Contains(output.String(), "--fmt") || strings.Contains(output.String(), "--format") ||
+				if strings.Contains(output.String(), "--fmt") || strings.Contains(output.String(), "--style") ||
 					(test.override && strings.Contains(output.String(), "pick → inspect")) {
 					t.Errorf("help exposes a descendant flag or overridden destination: %q", output.String())
 				}
@@ -920,7 +920,7 @@ func TestAliasHelpTargetsGroupsAndDiscoveryViews(t *testing.T) {
 			inputBuilds++
 			return struct{}{}
 		},
-		Flags: []Flag[struct{}]{ValueFlag(FlagMeta{Name: "format"}, (*string)(nil),
+		Flags: []Flag[struct{}]{ValueFlag(FlagMeta{Name: "style"}, (*string)(nil),
 			func(value string) (string, error) { return value, nil },
 			func(*struct{}, Supplied[string]) {},
 		)},
@@ -939,7 +939,7 @@ func TestAliasHelpTargetsGroupsAndDiscoveryViews(t *testing.T) {
 		Alias("pk", "promptkit"),
 		Alias("pk list bundles", "promptkit show prompt"),
 		FlagAlias("--hlep", "--help"),
-		FlagAliasFor("promptkit show prompt", "--fmt", "--format"),
+		FlagAliasFor("promptkit show prompt", "--fmt", "--style"),
 	)
 	if err != nil {
 		t.Fatal(err)
@@ -985,13 +985,13 @@ func TestAliasHelpTargetsGroupsAndDiscoveryViews(t *testing.T) {
 		{
 			name: "scoped flag alias appears on canonical command help",
 			args: []string{"promptkit", "show", "prompt", "--hlep"},
-			want: []string{"--fmt → --format"},
+			want: []string{"--fmt → --style"},
 		},
 		{
 			name: "group excludes descendant scoped flag aliases",
 			args: []string{"promptkit", "--help"},
 			want: []string{"Command Aliases:"},
-			omit: []string{"--fmt → --format"},
+			omit: []string{"--fmt → --style"},
 		},
 		{
 			name: "root lists explicit command aliases separately",