diff --git a/cmd/picoclaw/internal/model/add.go b/cmd/picoclaw/internal/model/add.go
new file mode 100644
index 000000000..b3ebba340
--- /dev/null
+++ b/cmd/picoclaw/internal/model/add.go
@@ -0,0 +1,200 @@
+package model
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+
+	"github.com/spf13/cobra"
+
+	"github.com/sipeed/picoclaw/cmd/picoclaw/internal"
+	"github.com/sipeed/picoclaw/pkg/config"
+)
+
+const defaultAliasName = "custom-prefer"
+
+func newAddCommand() *cobra.Command {
+	var (
+		apiBase   string
+		apiKey    string
+		modelID   string
+		alias     string
+		modelType string
+	)
+
+	cmd := &cobra.Command{
+		Use:   "add",
+		Short: "Add a model from an OpenAI-compatible endpoint",
+		Long: `Add a model entry by querying an OpenAI-compatible endpoint exposing
+GET <api-base>/models, then setting it as the default model.
+
+If --model is omitted, the available models are listed and you can pick one
+interactively. If --model is provided, the entry is written without contacting
+the server.
+
+Sample interactive session (key shown masked):
+
+    $ picoclaw model add \
+        -b https://ark.cn-beijing.volces.com/api/v3 \
+        -k 7dff****-****-****-****-********e829
+
+    115 model(s) available:
+        1) doubao-lite-128k-240428    (doubao-lite-128k)
+        2) doubao-pro-128k-240515     (doubao-pro-128k)
+        ...
+       48) deepseek-r1-250120          (deepseek-r1)
+       78) kimi-k2-250711              (kimi-k2)
+        ...
+      115) doubao-seed3d-2-0-260328    (doubao-seed3d-2-0)
+    Pick a model (number or id): 48
+    ✓ Saved model 'custom-prefer' (deepseek-r1-250120) and set as default.`,
+		Example: `  picoclaw model add --api-base https://api.openai.com/v1 --api-key sk-...
+  picoclaw model add -b http://localhost:8000/v1 -k dummy -m my-model -n local`,
+		Args: cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			return runAdd(addOptions{
+				apiBase:   strings.TrimSpace(apiBase),
+				apiKey:    strings.TrimSpace(apiKey),
+				modelID:   strings.TrimSpace(modelID),
+				alias:     strings.TrimSpace(alias),
+				modelType: strings.TrimSpace(modelType),
+				stdin:     cmd.InOrStdin(),
+				stdout:    cmd.OutOrStdout(),
+			})
+		},
+	}
+
+	cmd.Flags().StringVarP(&apiBase, "api-base", "b", "",
+		"API base URL (required), e.g. https://api.openai.com/v1")
+	cmd.Flags().StringVarP(&apiKey, "api-key", "k", "", "API key (required)")
+	cmd.Flags().StringVarP(&modelID, "model", "m", "",
+		"Model id; when set, skips the interactive picker and the network call")
+	cmd.Flags().StringVarP(&alias, "name", "n", defaultAliasName,
+		"Local alias written to model_list and used as the default model name")
+	cmd.Flags().StringVar(&modelType, "type", "openai-compatible",
+		"Endpoint type (only 'openai-compatible' is supported today)")
+	_ = cmd.MarkFlagRequired("api-base")
+	_ = cmd.MarkFlagRequired("api-key")
+
+	return cmd
+}
+
+type addOptions struct {
+	apiBase   string
+	apiKey    string
+	modelID   string
+	alias     string
+	modelType string
+	stdin     io.Reader
+	stdout    io.Writer
+}
+
+func runAdd(opt addOptions) error {
+	if opt.modelType != "" && opt.modelType != "openai-compatible" {
+		return fmt.Errorf("unsupported --type %q (only 'openai-compatible' is supported)", opt.modelType)
+	}
+	if opt.alias == "" {
+		opt.alias = defaultAliasName
+	}
+
+	selected := opt.modelID
+	if selected == "" {
+		entries, err := fetchOpenAIModels(opt.apiBase, opt.apiKey)
+		if err != nil {
+			return fmt.Errorf("fetch models: %w", err)
+		}
+		if len(entries) == 0 {
+			return fmt.Errorf("no models returned by %s", opt.apiBase)
+		}
+		selected, err = pickModel(opt.stdin, opt.stdout, entries)
+		if err != nil {
+			return err
+		}
+	}
+
+	return upsertModelDefault(opt.apiBase, opt.apiKey, opt.alias, selected, opt.stdout)
+}
+
+func pickModel(stdin io.Reader, stdout io.Writer, entries []modelEntry) (string, error) {
+	fmt.Fprintf(stdout, "\n%d model(s) available:\n", len(entries))
+	for i, m := range entries {
+		line := m.ID
+		if m.Name != "" && m.Name != m.ID {
+			line = fmt.Sprintf("%s (%s)", m.ID, m.Name)
+		}
+		fmt.Fprintf(stdout, "  %3d) %s\n", i+1, line)
+	}
+
+	scanner := bufio.NewScanner(stdin)
+	for {
+		fmt.Fprint(stdout, "Pick a model (number or id): ")
+		if !scanner.Scan() {
+			if err := scanner.Err(); err != nil {
+				return "", fmt.Errorf("read input: %w", err)
+			}
+			return "", fmt.Errorf("no selection provided")
+		}
+		text := strings.TrimSpace(scanner.Text())
+		if text == "" {
+			continue
+		}
+		if idx, err := strconv.Atoi(text); err == nil {
+			if idx < 1 || idx > len(entries) {
+				fmt.Fprintf(stdout, "Out of range. Enter 1-%d.\n", len(entries))
+				continue
+			}
+			return entries[idx-1].ID, nil
+		}
+		for _, m := range entries {
+			if m.ID == text {
+				return m.ID, nil
+			}
+		}
+		fmt.Fprintln(stdout, "Not a valid number or model id; try again.")
+	}
+}
+
+func upsertModelDefault(apiBase, apiKey, alias, modelID string, stdout io.Writer) error {
+	configPath := internal.GetConfigPath()
+	cfg, err := config.LoadConfig(configPath)
+	if err != nil {
+		return fmt.Errorf("failed to load config: %w", err)
+	}
+
+	secureKeys := config.SimpleSecureStrings(apiKey)
+
+	found := false
+	for _, m := range cfg.ModelList {
+		if m == nil {
+			continue
+		}
+		if m.ModelName == alias {
+			m.Model = modelID
+			m.APIBase = apiBase
+			m.APIKeys = secureKeys
+			m.Enabled = true
+			found = true
+			break
+		}
+	}
+	if !found {
+		cfg.ModelList = append(cfg.ModelList, &config.ModelConfig{
+			ModelName: alias,
+			Model:     modelID,
+			APIBase:   apiBase,
+			APIKeys:   secureKeys,
+			Enabled:   true,
+		})
+	}
+
+	cfg.Agents.Defaults.ModelName = alias
+
+	if err := config.SaveConfig(configPath, cfg); err != nil {
+		return fmt.Errorf("failed to save config: %w", err)
+	}
+
+	fmt.Fprintf(stdout, "✓ Saved model '%s' (%s) and set as default.\n", alias, modelID)
+	return nil
+}
diff --git a/cmd/picoclaw/internal/model/add_test.go b/cmd/picoclaw/internal/model/add_test.go
new file mode 100644
index 000000000..5da4d5e7f
--- /dev/null
+++ b/cmd/picoclaw/internal/model/add_test.go
@@ -0,0 +1,257 @@
+package model
+
+import (
+	"bytes"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/sipeed/picoclaw/pkg/config"
+)
+
+func TestFetchOpenAIModels_DataEnvelope(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, "/models", r.URL.Path)
+		assert.Equal(t, "Bearer secret", r.Header.Get("Authorization"))
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`{"data":[{"id":"gpt-foo","name":"Foo"},{"id":"gpt-bar"}]}`))
+	}))
+	defer srv.Close()
+
+	entries, err := fetchOpenAIModels(srv.URL, "secret")
+	require.NoError(t, err)
+	require.Len(t, entries, 2)
+	assert.Equal(t, "gpt-foo", entries[0].ID)
+	assert.Equal(t, "Foo", entries[0].Name)
+	assert.Equal(t, "gpt-bar", entries[1].ID)
+}
+
+func TestFetchOpenAIModels_BareArray(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`[{"id":"a"},{"id":"b"}]`))
+	}))
+	defer srv.Close()
+
+	entries, err := fetchOpenAIModels(srv.URL, "secret")
+	require.NoError(t, err)
+	require.Len(t, entries, 2)
+	assert.Equal(t, "a", entries[0].ID)
+	assert.Equal(t, "b", entries[1].ID)
+}
+
+func TestFetchOpenAIModels_TrimsTrailingSlash(t *testing.T) {
+	var gotPath string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotPath = r.URL.Path
+		_, _ = w.Write([]byte(`{"data":[{"id":"x"}]}`))
+	}))
+	defer srv.Close()
+
+	_, err := fetchOpenAIModels(srv.URL+"/", "k")
+	require.NoError(t, err)
+	assert.Equal(t, "/models", gotPath)
+}
+
+func TestFetchOpenAIModels_HTTPError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		http.Error(w, "nope", http.StatusUnauthorized)
+	}))
+	defer srv.Close()
+
+	_, err := fetchOpenAIModels(srv.URL, "bad")
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "HTTP 401")
+}
+
+func TestFetchOpenAIModels_EmptyDataEnvelope(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		_, _ = w.Write([]byte(`{"data":[]}`))
+	}))
+	defer srv.Close()
+
+	entries, err := fetchOpenAIModels(srv.URL, "k")
+	require.NoError(t, err)
+	assert.Empty(t, entries)
+}
+
+func TestFetchOpenAIModels_EmptyBareArray(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		_, _ = w.Write([]byte(`[]`))
+	}))
+	defer srv.Close()
+
+	entries, err := fetchOpenAIModels(srv.URL, "k")
+	require.NoError(t, err)
+	assert.Empty(t, entries)
+}
+
+func TestFetchOpenAIModels_UnrecognizedShape(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		_, _ = w.Write([]byte(`{"models":"not-supported"}`))
+	}))
+	defer srv.Close()
+
+	_, err := fetchOpenAIModels(srv.URL, "k")
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "unrecognized shape")
+}
+
+func TestFetchOpenAIModels_RequiresInputs(t *testing.T) {
+	_, err := fetchOpenAIModels("", "k")
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "api base")
+
+	_, err = fetchOpenAIModels("https://example.com", "")
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "api key")
+}
+
+func TestPickModel_ByIndex(t *testing.T) {
+	entries := []modelEntry{{ID: "a"}, {ID: "b"}, {ID: "c"}}
+	out := &bytes.Buffer{}
+	got, err := pickModel(strings.NewReader("2\n"), out, entries)
+	require.NoError(t, err)
+	assert.Equal(t, "b", got)
+	assert.Contains(t, out.String(), "3 model(s) available")
+}
+
+func TestPickModel_ByID(t *testing.T) {
+	entries := []modelEntry{{ID: "alpha"}, {ID: "beta"}}
+	out := &bytes.Buffer{}
+	got, err := pickModel(strings.NewReader("beta\n"), out, entries)
+	require.NoError(t, err)
+	assert.Equal(t, "beta", got)
+}
+
+func TestPickModel_RetriesOnInvalid(t *testing.T) {
+	entries := []modelEntry{{ID: "x"}}
+	out := &bytes.Buffer{}
+	got, err := pickModel(strings.NewReader("\n9\nnot-a-model\nx\n"), out, entries)
+	require.NoError(t, err)
+	assert.Equal(t, "x", got)
+	rendered := out.String()
+	assert.Contains(t, rendered, "Out of range")
+	assert.Contains(t, rendered, "Not a valid number")
+}
+
+func TestRunAdd_WithExplicitModel_NoNetwork(t *testing.T) {
+	initTest(t)
+
+	out := &bytes.Buffer{}
+	err := runAdd(addOptions{
+		apiBase:   "https://invalid.invalid/v1",
+		apiKey:    "k",
+		modelID:   "explicit-model",
+		alias:     "myalias",
+		modelType: "openai-compatible",
+		stdout:    out,
+	})
+	require.NoError(t, err)
+	assert.Contains(t, out.String(), "Saved model 'myalias' (explicit-model)")
+
+	cfg, err := config.LoadConfig(configPath)
+	require.NoError(t, err)
+	assert.Equal(t, "myalias", cfg.Agents.Defaults.GetModelName())
+	added := findModelByName(cfg, "myalias")
+	require.NotNil(t, added, "expected model 'myalias' in model_list")
+	assert.Equal(t, "explicit-model", added.Model)
+	assert.Equal(t, "https://invalid.invalid/v1", added.APIBase)
+	assert.True(t, added.Enabled)
+	require.Len(t, added.APIKeys, 1)
+	assert.Equal(t, "k", added.APIKeys[0].String())
+}
+
+func findModelByName(cfg *config.Config, name string) *config.ModelConfig {
+	for _, m := range cfg.ModelList {
+		if m != nil && m.ModelName == name {
+			return m
+		}
+	}
+	return nil
+}
+
+func TestRunAdd_FetchAndPick(t *testing.T) {
+	initTest(t)
+
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, "Bearer my-key", r.Header.Get("Authorization"))
+		_, _ = w.Write([]byte(`{"data":[{"id":"m1"},{"id":"m2"}]}`))
+	}))
+	defer srv.Close()
+
+	out := &bytes.Buffer{}
+	err := runAdd(addOptions{
+		apiBase:   srv.URL,
+		apiKey:    "my-key",
+		alias:     defaultAliasName,
+		modelType: "openai-compatible",
+		stdin:     strings.NewReader("2\n"),
+		stdout:    out,
+	})
+	require.NoError(t, err)
+
+	cfg, err := config.LoadConfig(configPath)
+	require.NoError(t, err)
+	assert.Equal(t, defaultAliasName, cfg.Agents.Defaults.GetModelName())
+	added := findModelByName(cfg, defaultAliasName)
+	require.NotNil(t, added)
+	assert.Equal(t, "m2", added.Model)
+}
+
+func TestRunAdd_UpsertsExistingAlias(t *testing.T) {
+	initTest(t)
+
+	first := &bytes.Buffer{}
+	require.NoError(t, runAdd(addOptions{
+		apiBase: "https://a.example/v1",
+		apiKey:  "k1",
+		modelID: "m1",
+		alias:   "shared",
+		stdout:  first,
+	}))
+
+	second := &bytes.Buffer{}
+	require.NoError(t, runAdd(addOptions{
+		apiBase: "https://b.example/v1",
+		apiKey:  "k2",
+		modelID: "m2",
+		alias:   "shared",
+		stdout:  second,
+	}))
+
+	cfg, err := config.LoadConfig(configPath)
+	require.NoError(t, err)
+	matches := 0
+	for _, m := range cfg.ModelList {
+		if m != nil && m.ModelName == "shared" {
+			matches++
+		}
+	}
+	assert.Equal(t, 1, matches, "alias should be updated, not duplicated")
+
+	updated := findModelByName(cfg, "shared")
+	require.NotNil(t, updated)
+	assert.Equal(t, "m2", updated.Model)
+	assert.Equal(t, "https://b.example/v1", updated.APIBase)
+	assert.Equal(t, "k2", updated.APIKeys[0].String())
+}
+
+func TestRunAdd_RejectsUnsupportedType(t *testing.T) {
+	initTest(t)
+
+	err := runAdd(addOptions{
+		apiBase:   "https://x/v1",
+		apiKey:    "k",
+		modelID:   "m",
+		alias:     "a",
+		modelType: "anthropic",
+		stdout:    &bytes.Buffer{},
+	})
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "unsupported --type")
+}
diff --git a/cmd/picoclaw/internal/model/command.go b/cmd/picoclaw/internal/model/command.go
index 330734b82..c412993a0 100644
--- a/cmd/picoclaw/internal/model/command.go
+++ b/cmd/picoclaw/internal/model/command.go
@@ -21,11 +21,17 @@ func NewModelCommand() *cobra.Command {
 If no argument is provided, shows the current default model.
 If a model name is provided, sets it as the default model.
 
+To onboard a model from a custom OpenAI-compatible endpoint (fetch the
+available list online and pick one), use the 'add' subcommand:
+
+  picoclaw model add --help
+
 Examples:
   picoclaw model                    # Show current default model
   picoclaw model gpt-5.2           # Set gpt-5.2 as default
   picoclaw model claude-sonnet-4.6 # Set claude-sonnet-4.6 as default
   picoclaw model local-model       # Set local VLLM server as default
+  picoclaw model add -b URL -k KEY # Add a model from a custom endpoint
 
 Note: 'local-model' is a special value for using a local VLLM server
 (running at localhost:8000 by default) which does not require an API key.`,
@@ -51,6 +57,8 @@ Note: 'local-model' is a special value for using a local VLLM server
 		},
 	}
 
+	cmd.AddCommand(newAddCommand())
+
 	return cmd
 }
 
@@ -66,6 +74,9 @@ func showCurrentModel(cfg *config.Config) {
 		fmt.Println("\nAvailable models in your config:")
 		listAvailableModels(cfg)
 	}
+
+	fmt.Println("\nTip: 'picoclaw model add -b URL -k KEY' adds a model from a custom")
+	fmt.Println("     OpenAI-compatible endpoint (see 'picoclaw model add --help').")
 }
 
 func listAvailableModels(cfg *config.Config) {
diff --git a/cmd/picoclaw/internal/model/online.go b/cmd/picoclaw/internal/model/online.go
new file mode 100644
index 000000000..9b8f7811d
--- /dev/null
+++ b/cmd/picoclaw/internal/model/online.go
@@ -0,0 +1,77 @@
+package model
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+)
+
+type modelEntry struct {
+	ID          string `json:"id"`
+	Name        string `json:"name"`
+	Description string `json:"description"`
+}
+
+type modelsAPIResponse struct {
+	Data []modelEntry `json:"data"`
+}
+
+// fetchOpenAIModels GETs <baseURL>/models with Bearer auth and accepts both the
+// {data:[…]} envelope and a bare array shape used by various OpenAI-compatible servers.
+func fetchOpenAIModels(baseURL, apiKey string) ([]modelEntry, error) {
+	if strings.TrimSpace(baseURL) == "" {
+		return nil, fmt.Errorf("api base is required")
+	}
+	if strings.TrimSpace(apiKey) == "" {
+		return nil, fmt.Errorf("api key is required")
+	}
+
+	url := strings.TrimRight(baseURL, "/") + "/models"
+
+	client := &http.Client{Timeout: 15 * time.Second}
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("build request: %w", err)
+	}
+	req.Header.Set("Authorization", "Bearer "+apiKey)
+
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("request failed: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		body, _ := io.ReadAll(io.LimitReader(resp.Body, 512))
+		return nil, fmt.Errorf("HTTP %d: %s", resp.StatusCode, strings.TrimSpace(string(body)))
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("read response: %w", err)
+	}
+
+	// {"data": [...]} envelope. Distinguish "envelope shape with empty list"
+	// from "object without a data key" via Data being non-nil after unmarshal:
+	// json.Unmarshal sets Data to []modelEntry{} for `{"data":[]}` but leaves
+	// it as nil when "data" is absent or null.
+	var envelope modelsAPIResponse
+	if err := json.Unmarshal(body, &envelope); err == nil && envelope.Data != nil {
+		return envelope.Data, nil
+	}
+
+	// Bare-array shape, including `[]`.
+	var arr []modelEntry
+	if err := json.Unmarshal(body, &arr); err == nil {
+		return arr, nil
+	}
+
+	preview := body
+	if len(preview) > 256 {
+		preview = preview[:256]
+	}
+	return nil, fmt.Errorf("decode response: unrecognized shape: %s", strings.TrimSpace(string(preview)))
+}