feat(providers): add zero providers models to discover a provider's models

`zero providers` had no way to list the models a provider actually serves, so a
custom OpenAI-/Anthropic-compatible endpoint (e.g. a self-hosted proxy serving a
dozen models) forced users to hand-write a config object per model. Live model
discovery already existed for the TUI picker but had no headless CLI surface.

Add `zero providers models [name] [--json]`: it probes the provider's live
model-listing endpoint (an OpenAI-compatible /v1/models or the Anthropic /models)
via providermodeldiscovery.Discover, using the profile's base URL and resolved
credential (inline -> stored -> env). This uses the raw discovery primitive with
no curated-catalog merge or coding-model filtering, so a custom provider's full
model list is returned. Configure the provider once, run `zero providers models`
to see what it serves, and use any id with `zero exec --model <id>` (Zero passes
unknown model ids through to the provider) -- no per-model config needed.

Wired through a new appDeps.discoverProviderModels hook (default:
providermodeldiscovery.Discover) so the command is unit-tested hermetically.

Fixes #381.

internal/cli/app.go

@@ -22,6 +22,7 @@ import (
 	"github.com/Gitlawb/zero/internal/observability"
 	"github.com/Gitlawb/zero/internal/plugins"
 	"github.com/Gitlawb/zero/internal/providerhealth"
+	"github.com/Gitlawb/zero/internal/providermodeldiscovery"
 	"github.com/Gitlawb/zero/internal/provideronboarding"
 	"github.com/Gitlawb/zero/internal/providers"
 	"github.com/Gitlawb/zero/internal/redaction"
@@ -53,32 +54,33 @@ type appDeps struct {
 	// config.SetActiveProviderEnv, set in defaultAppDeps — deliberately NOT filled
 	// by fillAppDeps, so tests never mutate the process environment unless they
 	// inject it). nil ⇒ no export.
-	exportActiveProvider  func(providerName string)
-	probeProviderHealth   func(context.Context, providerhealth.Options) providerhealth.Result
-	detectLocalRuntimes   func(context.Context, provideronboarding.LocalDetectOptions) []provideronboarding.DetectedLocalRuntime
-	newSessionStore       func() *sessions.Store
-	loadPlugins           func(plugins.LoadOptions) (plugins.LoadResult, error)
-	loadHooks             func(hooks.LoadOptions) (hooks.LoadResult, error)
-	skillsDir             func() string
-	pluginsDir            func() string
-	toolsDir              func() string
-	newMCPStore           func() (*mcp.PermissionStore, error)
-	newMCPTokenStore      func() (*mcp.TokenStore, error)
-	newSandboxStore       func() (*sandbox.GrantStore, error)
-	selectSandboxBackend  func(sandbox.BackendOptions) sandbox.Backend
-	runSandboxSetupHelper func(path string, args []string, stdout io.Writer, stderr io.Writer) error
-	registerMCPTools      func(context.Context, *tools.Registry, config.MCPConfig, mcp.RegisterOptions) (mcpToolRuntime, error)
-	prepareWorktree       func(context.Context, worktrees.Options) (worktrees.Result, error)
-	detectVerifyPlan      func(string) (verify.Plan, error)
-	runVerify             func(context.Context, verify.Plan, verify.RunOptions) verify.Report
-	runSelfVerify         func(context.Context, verify.Plan, selfverify.Options) selfverify.Report
-	runAgentEval          func(context.Context, agentEvalOptions) (agentEvalReport, error)
-	inspectChanges        func(context.Context, zerogit.InspectOptions) (zerogit.ChangeSummary, error)
-	commitChanges         func(context.Context, zerogit.CommitOptions) (zerogit.CommitResult, error)
-	runTUI                func(context.Context, tui.Options) int
-	runEditor             func(string) error
-	checkUpdate           func(context.Context, update.Options) (update.Result, error)
-	now                   func() time.Time
+	exportActiveProvider   func(providerName string)
+	probeProviderHealth    func(context.Context, providerhealth.Options) providerhealth.Result
+	discoverProviderModels func(context.Context, config.ProviderProfile) ([]providermodeldiscovery.Model, error)
+	detectLocalRuntimes    func(context.Context, provideronboarding.LocalDetectOptions) []provideronboarding.DetectedLocalRuntime
+	newSessionStore        func() *sessions.Store
+	loadPlugins            func(plugins.LoadOptions) (plugins.LoadResult, error)
+	loadHooks              func(hooks.LoadOptions) (hooks.LoadResult, error)
+	skillsDir              func() string
+	pluginsDir             func() string
+	toolsDir               func() string
+	newMCPStore            func() (*mcp.PermissionStore, error)
+	newMCPTokenStore       func() (*mcp.TokenStore, error)
+	newSandboxStore        func() (*sandbox.GrantStore, error)
+	selectSandboxBackend   func(sandbox.BackendOptions) sandbox.Backend
+	runSandboxSetupHelper  func(path string, args []string, stdout io.Writer, stderr io.Writer) error
+	registerMCPTools       func(context.Context, *tools.Registry, config.MCPConfig, mcp.RegisterOptions) (mcpToolRuntime, error)
+	prepareWorktree        func(context.Context, worktrees.Options) (worktrees.Result, error)
+	detectVerifyPlan       func(string) (verify.Plan, error)
+	runVerify              func(context.Context, verify.Plan, verify.RunOptions) verify.Report
+	runSelfVerify          func(context.Context, verify.Plan, selfverify.Options) selfverify.Report
+	runAgentEval           func(context.Context, agentEvalOptions) (agentEvalReport, error)
+	inspectChanges         func(context.Context, zerogit.InspectOptions) (zerogit.ChangeSummary, error)
+	commitChanges          func(context.Context, zerogit.CommitOptions) (zerogit.CommitResult, error)
+	runTUI                 func(context.Context, tui.Options) int
+	runEditor              func(string) error
+	checkUpdate            func(context.Context, update.Options) (update.Result, error)
+	now                    func() time.Time
 }
 
 type mcpToolRuntime interface {
@@ -134,8 +136,9 @@ func defaultAppDeps() appDeps {
 				OAuthLoginKey: loginKey,
 			})
 		},
-		probeProviderHealth: providerhealth.Probe,
-		detectLocalRuntimes: provideronboarding.DetectLocalRuntimes,
+		probeProviderHealth:    providerhealth.Probe,
+		discoverProviderModels: defaultDiscoverProviderModels,
+		detectLocalRuntimes:    provideronboarding.DetectLocalRuntimes,
 		newSessionStore: func() *sessions.Store {
 			return sessions.NewStore(sessions.StoreOptions{})
 		},
@@ -432,6 +435,9 @@ func fillAppDeps(deps appDeps) appDeps {
 	if deps.probeProviderHealth == nil {
 		deps.probeProviderHealth = defaults.probeProviderHealth
 	}
+	if deps.discoverProviderModels == nil {
+		deps.discoverProviderModels = defaults.discoverProviderModels
+	}
 	if deps.detectLocalRuntimes == nil {
 		deps.detectLocalRuntimes = defaults.detectLocalRuntimes
 	}

internal/cli/command_center.go

@@ -81,6 +81,9 @@ func runProviders(args []string, stdout io.Writer, stderr io.Writer, deps appDep
 	if command == "detect" {
 		return runProvidersDetect(args, stdout, stderr, deps)
 	}
+	if command == "models" {
+		return runProvidersModels(args, stdout, stderr, deps)
+	}
 	if command != "list" && command != "current" && command != "catalog" {
 		return writeExecUsageError(stderr, fmt.Sprintf("unknown providers command %q", command))
 	}
@@ -465,9 +468,11 @@ func writeProvidersHelp(w io.Writer) error {
   zero providers use <name> [flags]
   zero providers setup <catalog-id> [flags]
   zero providers detect [flags]
+  zero providers models [name] [flags]
 
 Inspects resolved provider profiles and provider catalog descriptors without printing secrets.
 Detect probes for running local runtimes (Ollama, LM Studio) and prints adopt commands plus per-provider next steps.
+Models probes a provider's live model-listing endpoint (e.g. an OpenAI-compatible /v1/models) and lists the models it serves — including custom OpenAI-/Anthropic-compatible endpoints — so a self-hosted provider needs no per-model config.
 
 Flags:
       --json                    Print JSON summary

internal/cli/provider_models.go

@@ -0,0 +1,148 @@
+package cli
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"github.com/Gitlawb/zero/internal/config"
+	"github.com/Gitlawb/zero/internal/providermodeldiscovery"
+)
+
+type providerModelsOptions struct {
+	name string
+	json bool
+}
+
+// runProvidersModels lists the models a saved provider actually serves by probing
+// its live model-discovery endpoint (e.g. an OpenAI-compatible `/v1/models`). It
+// works for custom OpenAI-/Anthropic-compatible providers too: discovery runs off
+// the profile's base URL + credentials, so a self-hosted endpoint serving a dozen
+// models no longer needs a config object per model — configure the provider once,
+// then run any listed model with `zero exec --model <id>` (Zero passes unknown
+// model ids through to the provider).
+func runProvidersModels(args []string, stdout io.Writer, stderr io.Writer, deps appDeps) int {
+	options, help, err := parseProviderModelsArgs(args)
+	if err != nil {
+		return writeExecUsageError(stderr, err.Error())
+	}
+	if help {
+		if err := writeProvidersHelp(stdout); err != nil {
+			return exitCrash
+		}
+		return exitSuccess
+	}
+
+	resolved, exitCode := resolveCommandCenterConfig(stderr, deps)
+	if exitCode != exitSuccess {
+		return exitCode
+	}
+	profile, err := selectProviderForCheck(resolved, options.name)
+	if err != nil {
+		return writeExecUsageError(stderr, err.Error())
+	}
+
+	ctx, stop := signalContext()
+	defer stop()
+	models, err := deps.discoverProviderModels(ctx, discoveryCredentialProfile(profile))
+	if err != nil {
+		return writeAppError(stderr, err.Error(), exitProvider)
+	}
+
+	if options.json {
+		items := make([]map[string]any, 0, len(models))
+		for _, model := range models {
+			entry := map[string]any{"id": model.ID}
+			if description := strings.TrimSpace(model.Description); description != "" {
+				entry["description"] = description
+			}
+			items = append(items, entry)
+		}
+		payload := map[string]any{
+			"provider": profile.Name,
+			"count":    len(items),
+			"models":   items,
+		}
+		if err := writePrettyJSON(stdout, payload); err != nil {
+			return exitCrash
+		}
+		return exitSuccess
+	}
+
+	name := strings.TrimSpace(profile.Name)
+	if name == "" {
+		name = "provider"
+	}
+	if _, err := fmt.Fprintf(stdout, "Provider models (%s)\n", name); err != nil {
+		return exitCrash
+	}
+	for _, model := range models {
+		line := strings.TrimSpace(model.ID)
+		if description := strings.TrimSpace(model.Description); description != "" {
+			line += " — " + description
+		}
+		if _, err := fmt.Fprintln(stdout, line); err != nil {
+			return exitCrash
+		}
+	}
+	suffix := "s"
+	if len(models) == 1 {
+		suffix = ""
+	}
+	if _, err := fmt.Fprintf(stdout, "%d model%s discovered\n", len(models), suffix); err != nil {
+		return exitCrash
+	}
+	if len(models) > 0 {
+		if _, err := fmt.Fprintf(stdout, "next: zero exec %q --model %s\n", "hello", setupCommandArg(models[0].ID)); err != nil {
+			return exitCrash
+		}
+	}
+	return exitSuccess
+}
+
+// discoveryCredentialProfile resolves the profile's API key the same way the
+// runtime does — inline, then the stored credential, then the configured env var —
+// so a `providers models` probe authenticates exactly like a real request. Mirrors
+// discoveredModelContextWindow's credential resolution.
+func discoveryCredentialProfile(profile config.ProviderProfile) config.ProviderProfile {
+	authed := profile
+	if strings.TrimSpace(authed.APIKey) == "" {
+		if store, err := config.ProviderKeyStore(); err == nil {
+			authed = config.ApplyStoredAPIKey(authed, store)
+		}
+	}
+	if strings.TrimSpace(authed.APIKey) == "" && strings.TrimSpace(authed.APIKeyEnv) != "" {
+		authed.APIKey = strings.TrimSpace(os.Getenv(authed.APIKeyEnv))
+	}
+	return authed
+}
+
+// defaultDiscoverProviderModels is the production discovery hook: a live probe of
+// the provider's model-listing endpoint with no curated-catalog merge or
+// coding-model filtering, so a custom provider's full model list is returned.
+func defaultDiscoverProviderModels(ctx context.Context, profile config.ProviderProfile) ([]providermodeldiscovery.Model, error) {
+	return providermodeldiscovery.Discover(ctx, profile, providermodeldiscovery.Options{})
+}
+
+func parseProviderModelsArgs(args []string) (providerModelsOptions, bool, error) {
+	options := providerModelsOptions{}
+	for index := 0; index < len(args); index++ {
+		arg := args[index]
+		switch {
+		case arg == "-h" || arg == "--help" || arg == "help":
+			return options, true, nil
+		case arg == "--json":
+			options.json = true
+		case strings.HasPrefix(arg, "-"):
+			return options, false, execUsageError{fmt.Sprintf("unknown flag %q", arg)}
+		default:
+			if options.name != "" {
+				return options, false, execUsageError{fmt.Sprintf("unexpected argument %q", arg)}
+			}
+			options.name = arg
+		}
+	}
+	return options, false, nil
+}

internal/cli/provider_models_test.go

@@ -0,0 +1,151 @@
+package cli
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"strings"
+	"testing"
+
+	"github.com/Gitlawb/zero/internal/config"
+	"github.com/Gitlawb/zero/internal/providermodeldiscovery"
+)
+
+func TestRunProvidersModelsListsDiscoveredModels(t *testing.T) {
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	deps := commandCenterDeps(t)
+	var probed config.ProviderProfile
+	deps.discoverProviderModels = func(_ context.Context, profile config.ProviderProfile) ([]providermodeldiscovery.Model, error) {
+		probed = profile
+		return []providermodeldiscovery.Model{
+			{ID: "team/model-a", Description: "first"},
+			{ID: "team/model-b"},
+		}, nil
+	}
+
+	exitCode := runWithDeps([]string{"providers", "models"}, &stdout, &stderr, deps)
+
+	if exitCode != exitSuccess {
+		t.Fatalf("exit = %d, want %d: %s", exitCode, exitSuccess, stderr.String())
+	}
+	// No name given → the active provider is probed, with its resolved credential.
+	if probed.Name != "work" {
+		t.Fatalf("probed provider = %q, want active provider work", probed.Name)
+	}
+	out := stdout.String()
+	for _, want := range []string{"Provider models (work)", "team/model-a — first", "team/model-b", "2 models discovered", "--model team/model-a"} {
+		if !strings.Contains(out, want) {
+			t.Fatalf("output missing %q:\n%s", want, out)
+		}
+	}
+}
+
+func TestRunProvidersModelsJSON(t *testing.T) {
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	deps := commandCenterDeps(t)
+	deps.discoverProviderModels = func(_ context.Context, _ config.ProviderProfile) ([]providermodeldiscovery.Model, error) {
+		return []providermodeldiscovery.Model{{ID: "m1", Description: "d1"}, {ID: "m2"}}, nil
+	}
+
+	exitCode := runWithDeps([]string{"providers", "models", "--json"}, &stdout, &stderr, deps)
+
+	if exitCode != exitSuccess {
+		t.Fatalf("exit = %d, want %d: %s", exitCode, exitSuccess, stderr.String())
+	}
+	var payload struct {
+		Provider string `json:"provider"`
+		Count    int    `json:"count"`
+		Models   []struct {
+			ID          string `json:"id"`
+			Description string `json:"description"`
+		} `json:"models"`
+	}
+	if err := json.Unmarshal(stdout.Bytes(), &payload); err != nil {
+		t.Fatalf("decode json: %v\n%s", err, stdout.String())
+	}
+	if payload.Provider != "work" || payload.Count != 2 || len(payload.Models) != 2 {
+		t.Fatalf("payload = %#v", payload)
+	}
+	if payload.Models[0].ID != "m1" || payload.Models[0].Description != "d1" {
+		t.Fatalf("model[0] = %#v", payload.Models[0])
+	}
+	// A model with no description omits the field rather than emitting an empty string.
+	if payload.Models[1].ID != "m2" || payload.Models[1].Description != "" {
+		t.Fatalf("model[1] = %#v", payload.Models[1])
+	}
+}
+
+func TestRunProvidersModelsSelectsNamedProvider(t *testing.T) {
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	deps := commandCenterDeps(t)
+	custom := config.ProviderProfile{
+		Name:         "self-hosted",
+		ProviderKind: config.ProviderKindOpenAICompatible,
+		BaseURL:      "https://models.internal/v1",
+		APIKey:       "sk-internal",
+		Model:        "house-model",
+	}
+	deps.resolveConfig = func(string, config.Overrides) (config.ResolvedConfig, error) {
+		work := config.ProviderProfile{Name: "work", ProviderKind: config.ProviderKindOpenAI, BaseURL: config.OpenAIBaseURL, APIKey: "sk", Model: "gpt-4.1"}
+		return config.ResolvedConfig{ActiveProvider: "work", Provider: work, Providers: []config.ProviderProfile{work, custom}}, nil
+	}
+	var probed config.ProviderProfile
+	deps.discoverProviderModels = func(_ context.Context, profile config.ProviderProfile) ([]providermodeldiscovery.Model, error) {
+		probed = profile
+		return []providermodeldiscovery.Model{{ID: "house-model"}}, nil
+	}
+
+	exitCode := runWithDeps([]string{"providers", "models", "self-hosted"}, &stdout, &stderr, deps)
+
+	if exitCode != exitSuccess {
+		t.Fatalf("exit = %d, want %d: %s", exitCode, exitSuccess, stderr.String())
+	}
+	if probed.Name != "self-hosted" || probed.BaseURL != "https://models.internal/v1" {
+		t.Fatalf("probed = %#v, want the named custom provider", probed)
+	}
+}
+
+func TestRunProvidersModelsUnknownProviderFails(t *testing.T) {
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	deps := commandCenterDeps(t)
+	called := false
+	deps.discoverProviderModels = func(_ context.Context, _ config.ProviderProfile) ([]providermodeldiscovery.Model, error) {
+		called = true
+		return nil, nil
+	}
+
+	exitCode := runWithDeps([]string{"providers", "models", "ghost"}, &stdout, &stderr, deps)
+
+	if exitCode == exitSuccess {
+		t.Fatalf("exit = %d, want non-zero for unknown provider", exitCode)
+	}
+	if called {
+		t.Fatal("discovery must not run for an unknown provider")
+	}
+	if !strings.Contains(stderr.String(), `provider "ghost" not found`) {
+		t.Fatalf("stderr = %q, want provider-not-found", stderr.String())
+	}
+}
+
+func TestRunProvidersModelsSurfacesDiscoveryError(t *testing.T) {
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	deps := commandCenterDeps(t)
+	deps.discoverProviderModels = func(_ context.Context, _ config.ProviderProfile) ([]providermodeldiscovery.Model, error) {
+		return nil, errors.New("models endpoint returned 404")
+	}
+
+	exitCode := runWithDeps([]string{"providers", "models"}, &stdout, &stderr, deps)
+
+	if exitCode != exitProvider {
+		t.Fatalf("exit = %d, want exitProvider %d", exitCode, exitProvider)
+	}
+	if !strings.Contains(stderr.String(), "models endpoint returned 404") {
+		t.Fatalf("stderr = %q, want the discovery error", stderr.String())
+	}
+}