feat(agents): add chat model pricing metadata (#22959)

## Summary
- add chat model pricing metadata to the agents admin form and SDK
metadata
- split pricing into its own section and show default pricing as
placeholders
- apply default pricing when admins leave pricing fields blank

coderd/chatd/chatprovider/chatprovider.go

@@ -553,7 +553,8 @@ func normalizedEnumValue(value string, allowed ...string) *string {
 	return nil
 }
 
-// MergeMissingCallConfig fills unset call config values from defaults.
+// MergeMissingCallConfig fills unset call config values from a provider or
+// profile default config.
 func MergeMissingCallConfig(
 	dst *codersdk.ChatModelCallConfig,
 	defaults codersdk.ChatModelCallConfig,
@@ -576,9 +577,39 @@ func MergeMissingCallConfig(
 	if dst.FrequencyPenalty == nil {
 		dst.FrequencyPenalty = defaults.FrequencyPenalty
 	}
+	MergeMissingModelCostConfig(&dst.Cost, defaults.Cost)
 	MergeMissingProviderOptions(&dst.ProviderOptions, defaults.ProviderOptions)
 }
 
+// MergeMissingModelCostConfig fills unset pricing metadata from defaults.
+func MergeMissingModelCostConfig(
+	dst **codersdk.ModelCostConfig,
+	defaults *codersdk.ModelCostConfig,
+) {
+	if defaults == nil {
+		return
+	}
+	if *dst == nil {
+		copied := *defaults
+		*dst = &copied
+		return
+	}
+
+	current := *dst
+	if current.InputPricePerMillionTokens == nil {
+		current.InputPricePerMillionTokens = defaults.InputPricePerMillionTokens
+	}
+	if current.OutputPricePerMillionTokens == nil {
+		current.OutputPricePerMillionTokens = defaults.OutputPricePerMillionTokens
+	}
+	if current.CacheReadPricePerMillionTokens == nil {
+		current.CacheReadPricePerMillionTokens = defaults.CacheReadPricePerMillionTokens
+	}
+	if current.CacheWritePricePerMillionTokens == nil {
+		current.CacheWritePricePerMillionTokens = defaults.CacheWritePricePerMillionTokens
+	}
+}
+
 // MergeMissingProviderOptions fills unset provider option fields from defaults.
 func MergeMissingProviderOptions(
 	dst **codersdk.ChatModelProviderOptions,

coderd/chatd/chatprovider/chatprovider_test.go

@@ -142,16 +142,25 @@ func TestMergeMissingCallConfig_FillsUnsetFields(t *testing.T) {
 
 	dst := codersdk.ChatModelCallConfig{
 		Temperature: float64Ptr(0.2),
+		Cost: &codersdk.ModelCostConfig{
+			OutputPricePerMillionTokens: float64Ptr(0.7),
+		},
 		ProviderOptions: &codersdk.ChatModelProviderOptions{
 			OpenAI: &codersdk.ChatModelOpenAIProviderOptions{
 				User: stringPtr("alice"),
 			},
 		},
 	}
-	defaults := codersdk.ChatModelCallConfig{
+	defaultCallConfig := codersdk.ChatModelCallConfig{
 		MaxOutputTokens: int64Ptr(512),
 		Temperature:     float64Ptr(0.9),
 		TopP:            float64Ptr(0.8),
+		Cost: &codersdk.ModelCostConfig{
+			InputPricePerMillionTokens:      float64Ptr(0.15),
+			OutputPricePerMillionTokens:     float64Ptr(0.9),
+			CacheReadPricePerMillionTokens:  float64Ptr(0.03),
+			CacheWritePricePerMillionTokens: float64Ptr(0.3),
+		},
 		ProviderOptions: &codersdk.ChatModelProviderOptions{
 			OpenAI: &codersdk.ChatModelOpenAIProviderOptions{
 				User:            stringPtr("bob"),
@@ -160,7 +169,7 @@ func TestMergeMissingCallConfig_FillsUnsetFields(t *testing.T) {
 		},
 	}
 
-	chatprovider.MergeMissingCallConfig(&dst, defaults)
+	chatprovider.MergeMissingCallConfig(&dst, defaultCallConfig)
 
 	require.NotNil(t, dst.MaxOutputTokens)
 	require.EqualValues(t, 512, *dst.MaxOutputTokens)
@@ -168,6 +177,15 @@ func TestMergeMissingCallConfig_FillsUnsetFields(t *testing.T) {
 	require.Equal(t, 0.2, *dst.Temperature)
 	require.NotNil(t, dst.TopP)
 	require.Equal(t, 0.8, *dst.TopP)
+	require.NotNil(t, dst.Cost)
+	require.NotNil(t, dst.Cost.InputPricePerMillionTokens)
+	require.Equal(t, 0.15, *dst.Cost.InputPricePerMillionTokens)
+	require.NotNil(t, dst.Cost.OutputPricePerMillionTokens)
+	require.Equal(t, 0.7, *dst.Cost.OutputPricePerMillionTokens)
+	require.NotNil(t, dst.Cost.CacheReadPricePerMillionTokens)
+	require.Equal(t, 0.03, *dst.Cost.CacheReadPricePerMillionTokens)
+	require.NotNil(t, dst.Cost.CacheWritePricePerMillionTokens)
+	require.Equal(t, 0.3, *dst.Cost.CacheWritePricePerMillionTokens)
 	require.NotNil(t, dst.ProviderOptions)
 	require.NotNil(t, dst.ProviderOptions.OpenAI)
 	require.Equal(t, "alice", *dst.ProviderOptions.OpenAI.User)

coderd/chats.go

@@ -3095,6 +3095,10 @@ func marshalChatModelCallConfig(
 		return json.RawMessage("{}"), nil
 	}
 
+	if err := validateChatModelCallConfig(modelConfig); err != nil {
+		return nil, err
+	}
+
 	encoded, err := json.Marshal(modelConfig)
 	if err != nil {
 		return nil, xerrors.Errorf("encode model config: %w", err)
@@ -3102,6 +3106,44 @@ func marshalChatModelCallConfig(
 	return encoded, nil
 }
 
+func validateChatModelCallConfig(modelConfig *codersdk.ChatModelCallConfig) error {
+	if modelConfig == nil {
+		return nil
+	}
+
+	costConfig := codersdk.ModelCostConfig{}
+	if modelConfig.Cost != nil {
+		costConfig = *modelConfig.Cost
+	}
+
+	pricingFields := []struct {
+		name  string
+		value *float64
+	}{
+		{name: "cost.input_price_per_million_tokens", value: costConfig.InputPricePerMillionTokens},
+		{name: "cost.output_price_per_million_tokens", value: costConfig.OutputPricePerMillionTokens},
+		{name: "cost.cache_read_price_per_million_tokens", value: costConfig.CacheReadPricePerMillionTokens},
+		{name: "cost.cache_write_price_per_million_tokens", value: costConfig.CacheWritePricePerMillionTokens},
+	}
+	for _, field := range pricingFields {
+		if err := validateNonNegativeFloat64Field(field.name, field.value); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func validateNonNegativeFloat64Field(name string, value *float64) error {
+	if value == nil {
+		return nil
+	}
+	if *value < 0 {
+		return xerrors.Errorf("%s must be greater than or equal to zero", name)
+	}
+	return nil
+}
+
 func unmarshalChatModelCallConfig(
 	raw json.RawMessage,
 ) *codersdk.ChatModelCallConfig {
@@ -3130,9 +3172,21 @@ func isZeroChatModelCallConfig(config *codersdk.ChatModelCallConfig) bool {
 		config.TopK == nil &&
 		config.PresencePenalty == nil &&
 		config.FrequencyPenalty == nil &&
+		isZeroModelCostConfig(config.Cost) &&
 		isZeroChatModelProviderOptions(config.ProviderOptions)
 }
 
+func isZeroModelCostConfig(cost *codersdk.ModelCostConfig) bool {
+	if cost == nil {
+		return true
+	}
+
+	return cost.InputPricePerMillionTokens == nil &&
+		cost.OutputPricePerMillionTokens == nil &&
+		cost.CacheReadPricePerMillionTokens == nil &&
+		cost.CacheWritePricePerMillionTokens == nil
+}
+
 func isZeroChatModelProviderOptions(options *codersdk.ChatModelProviderOptions) bool {
 	if options == nil {
 		return true

coderd/chats_test.go

@@ -22,6 +22,7 @@ import (
 	"github.com/coder/coder/v2/coderd/database/dbfake"
 	"github.com/coder/coder/v2/coderd/externalauth"
 	coderdpubsub "github.com/coder/coder/v2/coderd/pubsub"
+	"github.com/coder/coder/v2/coderd/util/ptr"
 	"github.com/coder/coder/v2/codersdk"
 	"github.com/coder/coder/v2/testutil"
 	"github.com/coder/websocket"
@@ -902,6 +903,48 @@ func TestListChatModelConfigs(t *testing.T) {
 		require.True(t, found)
 	})
 
+	t.Run("DeserializesLegacyPricingJSON", func(t *testing.T) {
+		t.Parallel()
+
+		ctx := testutil.Context(t, testutil.WaitLong)
+		client, db := newChatClientWithDatabase(t)
+		firstUser := coderdtest.CreateFirstUser(t, client)
+
+		_, err := client.CreateChatProvider(ctx, codersdk.CreateChatProviderConfigRequest{
+			Provider: "openai",
+			APIKey:   "test-api-key",
+		})
+		require.NoError(t, err)
+
+		legacyOptions := json.RawMessage(`{"input_price_per_million_tokens":0.15,"output_price_per_million_tokens":0.6,"cache_read_price_per_million_tokens":0.03,"cache_write_price_per_million_tokens":0.3}`)
+		storedConfig, err := db.InsertChatModelConfig(dbauthz.AsSystemRestricted(ctx), database.InsertChatModelConfigParams{
+			Provider:             "openai",
+			Model:                "gpt-4o-mini-legacy",
+			DisplayName:          "GPT-4o Mini Legacy",
+			CreatedBy:            uuid.NullUUID{UUID: firstUser.UserID, Valid: true},
+			UpdatedBy:            uuid.NullUUID{UUID: firstUser.UserID, Valid: true},
+			Enabled:              true,
+			IsDefault:            false,
+			ContextLimit:         4096,
+			CompressionThreshold: 80,
+			Options:              legacyOptions,
+		})
+		require.NoError(t, err)
+
+		configs, err := client.ListChatModelConfigs(ctx)
+		require.NoError(t, err)
+		require.Len(t, configs, 1)
+		require.Equal(t, storedConfig.ID, configs[0].ID)
+		requireChatModelPricing(t, configs[0].ModelConfig, &codersdk.ChatModelCallConfig{
+			Cost: &codersdk.ModelCostConfig{
+				InputPricePerMillionTokens:      ptr.Ref(0.15),
+				OutputPricePerMillionTokens:     ptr.Ref(0.6),
+				CacheReadPricePerMillionTokens:  ptr.Ref(0.03),
+				CacheWritePricePerMillionTokens: ptr.Ref(0.3),
+			},
+		})
+	})
+
 	t.Run("SuccessForOrganizationMember", func(t *testing.T) {
 		t.Parallel()
 
@@ -946,11 +989,20 @@ func TestCreateChatModelConfig(t *testing.T) {
 
 		contextLimit := int64(4096)
 		isDefault := true
+		pricing := &codersdk.ChatModelCallConfig{
+			Cost: &codersdk.ModelCostConfig{
+				InputPricePerMillionTokens:      ptr.Ref(0.15),
+				OutputPricePerMillionTokens:     ptr.Ref(0.6),
+				CacheReadPricePerMillionTokens:  ptr.Ref(0.03),
+				CacheWritePricePerMillionTokens: ptr.Ref(0.3),
+			},
+		}
 		modelConfig, err := client.CreateChatModelConfig(ctx, codersdk.CreateChatModelConfigRequest{
 			Provider:     "openai",
 			Model:        "gpt-4o-mini",
 			ContextLimit: &contextLimit,
 			IsDefault:    &isDefault,
+			ModelConfig:  pricing,
 		})
 		require.NoError(t, err)
 		require.NotEqual(t, uuid.Nil, modelConfig.ID)
@@ -958,6 +1010,45 @@ func TestCreateChatModelConfig(t *testing.T) {
 		require.Equal(t, "gpt-4o-mini", modelConfig.Model)
 		require.EqualValues(t, 4096, modelConfig.ContextLimit)
 		require.True(t, modelConfig.IsDefault)
+		requireChatModelPricing(t, modelConfig.ModelConfig, pricing)
+
+		configs, err := client.ListChatModelConfigs(ctx)
+		require.NoError(t, err)
+		require.Len(t, configs, 1)
+		requireChatModelPricing(t, configs[0].ModelConfig, pricing)
+	})
+
+	t.Run("RejectsNegativePricing", func(t *testing.T) {
+		t.Parallel()
+
+		ctx := testutil.Context(t, testutil.WaitLong)
+		client := newChatClient(t)
+		_ = coderdtest.CreateFirstUser(t, client)
+
+		_, err := client.CreateChatProvider(ctx, codersdk.CreateChatProviderConfigRequest{
+			Provider: "openai",
+			APIKey:   "test-api-key",
+		})
+		require.NoError(t, err)
+
+		contextLimit := int64(4096)
+		_, err = client.CreateChatModelConfig(ctx, codersdk.CreateChatModelConfigRequest{
+			Provider:     "openai",
+			Model:        "gpt-4o-mini",
+			ContextLimit: &contextLimit,
+			ModelConfig: &codersdk.ChatModelCallConfig{
+				Cost: &codersdk.ModelCostConfig{
+					InputPricePerMillionTokens: ptr.Ref(-0.01),
+				},
+			},
+		})
+		sdkErr := requireSDKError(t, err, http.StatusBadRequest)
+		require.Equal(t, "Invalid model config.", sdkErr.Message)
+		require.Equal(
+			t,
+			"cost.input_price_per_million_tokens must be greater than or equal to zero",
+			sdkErr.Detail,
+		)
 	})
 
 	t.Run("MissingContextLimit", func(t *testing.T) {
@@ -1028,14 +1119,53 @@ func TestUpdateChatModelConfig(t *testing.T) {
 		modelConfig := createChatModelConfig(t, client)
 
 		contextLimit := int64(8192)
+		pricing := &codersdk.ChatModelCallConfig{
+			Cost: &codersdk.ModelCostConfig{
+				InputPricePerMillionTokens:      ptr.Ref(0.2),
+				OutputPricePerMillionTokens:     ptr.Ref(0.8),
+				CacheReadPricePerMillionTokens:  ptr.Ref(0.04),
+				CacheWritePricePerMillionTokens: ptr.Ref(0.4),
+			},
+		}
 		updated, err := client.UpdateChatModelConfig(ctx, modelConfig.ID, codersdk.UpdateChatModelConfigRequest{
 			DisplayName:  "GPT-4o Mini Updated",
 			ContextLimit: &contextLimit,
+			ModelConfig:  pricing,
 		})
 		require.NoError(t, err)
 		require.Equal(t, modelConfig.ID, updated.ID)
 		require.Equal(t, "GPT-4o Mini Updated", updated.DisplayName)
 		require.EqualValues(t, 8192, updated.ContextLimit)
+		requireChatModelPricing(t, updated.ModelConfig, pricing)
+
+		configs, err := client.ListChatModelConfigs(ctx)
+		require.NoError(t, err)
+		require.Len(t, configs, 1)
+		requireChatModelPricing(t, configs[0].ModelConfig, pricing)
+	})
+
+	t.Run("RejectsNegativePricing", func(t *testing.T) {
+		t.Parallel()
+
+		ctx := testutil.Context(t, testutil.WaitLong)
+		client := newChatClient(t)
+		_ = coderdtest.CreateFirstUser(t, client)
+		modelConfig := createChatModelConfig(t, client)
+
+		_, err := client.UpdateChatModelConfig(ctx, modelConfig.ID, codersdk.UpdateChatModelConfigRequest{
+			ModelConfig: &codersdk.ChatModelCallConfig{
+				Cost: &codersdk.ModelCostConfig{
+					OutputPricePerMillionTokens: ptr.Ref(-1.0),
+				},
+			},
+		})
+		sdkErr := requireSDKError(t, err, http.StatusBadRequest)
+		require.Equal(t, "Invalid model config.", sdkErr.Message)
+		require.Equal(
+			t,
+			"cost.output_price_per_million_tokens must be greater than or equal to zero",
+			sdkErr.Detail,
+		)
 	})
 
 	t.Run("NotFound", func(t *testing.T) {
@@ -3303,6 +3433,28 @@ func TestGetChatFile(t *testing.T) {
 	})
 }
 
+func requireChatModelPricing(
+	t *testing.T,
+	actual *codersdk.ChatModelCallConfig,
+	expected *codersdk.ChatModelCallConfig,
+) {
+	t.Helper()
+	require.NotNil(t, actual)
+	require.NotNil(t, expected)
+
+	require.NotNil(t, actual.Cost)
+	require.NotNil(t, expected.Cost)
+	require.NotNil(t, actual.Cost.InputPricePerMillionTokens)
+	require.NotNil(t, actual.Cost.OutputPricePerMillionTokens)
+	require.NotNil(t, actual.Cost.CacheReadPricePerMillionTokens)
+	require.NotNil(t, actual.Cost.CacheWritePricePerMillionTokens)
+
+	require.Equal(t, *expected.Cost.InputPricePerMillionTokens, *actual.Cost.InputPricePerMillionTokens)
+	require.Equal(t, *expected.Cost.OutputPricePerMillionTokens, *actual.Cost.OutputPricePerMillionTokens)
+	require.Equal(t, *expected.Cost.CacheReadPricePerMillionTokens, *actual.Cost.CacheReadPricePerMillionTokens)
+	require.Equal(t, *expected.Cost.CacheWritePricePerMillionTokens, *actual.Cost.CacheWritePricePerMillionTokens)
+}
+
 func createChatModelConfig(t *testing.T, client *codersdk.Client) codersdk.ChatModelConfig {
 	t.Helper()
 

codersdk/chats.go

@@ -420,6 +420,17 @@ type ChatModelVercelProviderOptions struct {
 	ExtraBody         map[string]any                         `json:"extra_body,omitempty" description:"Additional fields to include in the request body" hidden:"true"`
 }
 
+// ModelCostConfig stores pricing metadata for a chat model.
+type ModelCostConfig struct {
+	// Pricing is stored as configuration metadata and currently only needs to
+	// round-trip cleanly through the API and admin UI. If we later use these
+	// values for billing-grade arithmetic, switch to a fixed-point type.
+	InputPricePerMillionTokens      *float64 `json:"input_price_per_million_tokens,omitempty" description:"Input token price in USD per 1M tokens"`
+	OutputPricePerMillionTokens     *float64 `json:"output_price_per_million_tokens,omitempty" description:"Output token price in USD per 1M tokens"`
+	CacheReadPricePerMillionTokens  *float64 `json:"cache_read_price_per_million_tokens,omitempty" description:"Cache read token price in USD per 1M tokens"`
+	CacheWritePricePerMillionTokens *float64 `json:"cache_write_price_per_million_tokens,omitempty" description:"Cache write or cache creation token price in USD per 1M tokens"`
+}
+
 // ChatModelCallConfig configures per-call model behavior defaults.
 type ChatModelCallConfig struct {
 	MaxOutputTokens  *int64                    `json:"max_output_tokens,omitempty" description:"Upper bound on tokens the model may generate"`
@@ -428,9 +439,52 @@ type ChatModelCallConfig struct {
 	TopK             *int64                    `json:"top_k,omitempty" description:"Number of highest-probability tokens to keep for sampling"`
 	PresencePenalty  *float64                  `json:"presence_penalty,omitempty" description:"Penalty for tokens that have already appeared in the output"`
 	FrequencyPenalty *float64                  `json:"frequency_penalty,omitempty" description:"Penalty for tokens based on their frequency in the output"`
+	Cost             *ModelCostConfig          `json:"cost,omitempty" description:"Optional pricing metadata for this model"`
 	ProviderOptions  *ChatModelProviderOptions `json:"provider_options,omitempty" description:"Provider-specific option overrides"`
 }
 
+// UnmarshalJSON accepts both the current nested cost object and the previous
+// top-level pricing keys so legacy stored model_config JSON continues to load.
+func (c *ChatModelCallConfig) UnmarshalJSON(data []byte) error {
+	type chatModelCallConfigAlias ChatModelCallConfig
+	aux := struct {
+		*chatModelCallConfigAlias
+		InputPricePerMillionTokens      *float64 `json:"input_price_per_million_tokens,omitempty"`
+		OutputPricePerMillionTokens     *float64 `json:"output_price_per_million_tokens,omitempty"`
+		CacheReadPricePerMillionTokens  *float64 `json:"cache_read_price_per_million_tokens,omitempty"`
+		CacheWritePricePerMillionTokens *float64 `json:"cache_write_price_per_million_tokens,omitempty"`
+	}{
+		chatModelCallConfigAlias: (*chatModelCallConfigAlias)(c),
+	}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+
+	if aux.InputPricePerMillionTokens == nil &&
+		aux.OutputPricePerMillionTokens == nil &&
+		aux.CacheReadPricePerMillionTokens == nil &&
+		aux.CacheWritePricePerMillionTokens == nil {
+		return nil
+	}
+
+	if c.Cost == nil {
+		c.Cost = &ModelCostConfig{}
+	}
+	if c.Cost.InputPricePerMillionTokens == nil {
+		c.Cost.InputPricePerMillionTokens = aux.InputPricePerMillionTokens
+	}
+	if c.Cost.OutputPricePerMillionTokens == nil {
+		c.Cost.OutputPricePerMillionTokens = aux.OutputPricePerMillionTokens
+	}
+	if c.Cost.CacheReadPricePerMillionTokens == nil {
+		c.Cost.CacheReadPricePerMillionTokens = aux.CacheReadPricePerMillionTokens
+	}
+	if c.Cost.CacheWritePricePerMillionTokens == nil {
+		c.Cost.CacheWritePricePerMillionTokens = aux.CacheWritePricePerMillionTokens
+	}
+	return nil
+}
+
 // CreateChatModelConfigRequest creates a chat model config.
 type CreateChatModelConfigRequest struct {
 	Provider             string               `json:"provider"`

docs/ai-coder/agents/models.md

@@ -113,6 +113,10 @@ These options apply to all providers:
 | Top K                 | Limits token selection to the top K candidates.                                                  |
 | Presence Penalty      | Penalizes tokens that have already appeared in the conversation.                                 |
 | Frequency Penalty     | Penalizes tokens proportional to how often they have appeared.                                   |
+| Input Price           | Optional USD price metadata for input tokens, recorded per 1M tokens.                            |
+| Output Price          | Optional USD price metadata for output tokens, recorded per 1M tokens.                           |
+| Cache Read Price      | Optional USD price metadata for cache read tokens, recorded per 1M tokens.                       |
+| Cache Write Price     | Optional USD price metadata for cache creation/write tokens, recorded per 1M tokens.             |
 
 ### Provider-specific options
 

site/src/api/chatModelOptionsGenerated.json

@@ -48,6 +48,38 @@
 				"description": "Penalty for tokens based on their frequency in the output",
 				"required": false,
 				"input_type": "input"
+			},
+			{
+				"json_name": "cost.input_price_per_million_tokens",
+				"go_name": "Cost.InputPricePerMillionTokens",
+				"type": "number",
+				"description": "Input token price in USD per 1M tokens",
+				"required": false,
+				"input_type": "input"
+			},
+			{
+				"json_name": "cost.output_price_per_million_tokens",
+				"go_name": "Cost.OutputPricePerMillionTokens",
+				"type": "number",
+				"description": "Output token price in USD per 1M tokens",
+				"required": false,
+				"input_type": "input"
+			},
+			{
+				"json_name": "cost.cache_read_price_per_million_tokens",
+				"go_name": "Cost.CacheReadPricePerMillionTokens",
+				"type": "number",
+				"description": "Cache read token price in USD per 1M tokens",
+				"required": false,
+				"input_type": "input"
+			},
+			{
+				"json_name": "cost.cache_write_price_per_million_tokens",
+				"go_name": "Cost.CacheWritePricePerMillionTokens",
+				"type": "number",
+				"description": "Cache write or cache creation token price in USD per 1M tokens",
+				"required": false,
+				"input_type": "input"
 			}
 		]
 	},

site/src/api/typesGenerated.ts

@@ -1273,6 +1273,7 @@ export interface ChatModelCallConfig {
 	readonly top_k?: number;
 	readonly presence_penalty?: number;
 	readonly frequency_penalty?: number;
+	readonly cost?: ModelCostConfig;
 	readonly provider_options?: ChatModelProviderOptions;
 }
 
@@ -3410,6 +3411,22 @@ export interface MinimalUser {
 	readonly avatar_url?: string;
 }
 
+// From codersdk/chats.go
+/**
+ * ModelCostConfig stores pricing metadata for a chat model.
+ */
+export interface ModelCostConfig {
+	/**
+	 * Pricing is stored as configuration metadata and currently only needs to
+	 * round-trip cleanly through the API and admin UI. If we later use these
+	 * values for billing-grade arithmetic, switch to a fixed-point type.
+	 */
+	readonly input_price_per_million_tokens?: number;
+	readonly output_price_per_million_tokens?: number;
+	readonly cache_read_price_per_million_tokens?: number;
+	readonly cache_write_price_per_million_tokens?: number;
+}
+
 // From netcheck/netcheck.go
 /**
  * Report contains the result of a single netcheck.

site/src/pages/AgentsPage/ChatModelAdminPanel/ChatModelAdminPanel.stories.tsx

@@ -39,6 +39,7 @@ const createModelConfig = (
 	is_default: overrides.is_default ?? false,
 	context_limit: overrides.context_limit ?? 200000,
 	compression_threshold: overrides.compression_threshold ?? 70,
+	model_config: overrides.model_config,
 	created_at: overrides.created_at ?? now,
 	updated_at: overrides.updated_at ?? now,
 });
@@ -125,6 +126,7 @@ const setupChatSpies = (state: {
 				Number.isFinite(req.compression_threshold)
 					? req.compression_threshold
 					: 70,
+			model_config: req.model_config,
 		});
 		state.modelConfigs = [...state.modelConfigs, created];
 		return created;
@@ -419,7 +421,7 @@ export const NoModelConfigByDefault: Story = {
 				model: "gpt-5-pro",
 			}),
 		);
-		// The request should not include a model_config key.
+		// Blank pricing fields should remain unset in the payload.
 		const callArgs = (
 			API.createChatModelConfig as unknown as ReturnType<typeof spyOn>
 		).mock.calls[0][0] as Record<string, unknown>;
@@ -621,6 +623,39 @@ export const ModelFormBedrock: Story = {
 	},
 };
 
+export const ModelPricingWarningInList: Story = {
+	args: { section: "models" as ChatModelAdminSection },
+	beforeEach: () => {
+		setupChatSpies({
+			providerConfigs: [
+				createProviderConfig({
+					id: "provider-openai",
+					provider: "openai",
+					display_name: "OpenAI",
+					source: "database",
+					has_api_key: true,
+				}),
+			],
+			modelConfigs: [
+				createModelConfig({
+					id: "model-warning",
+					provider: "openai",
+					model: "gpt-4.1",
+					display_name: "GPT-4.1",
+				}),
+			],
+			modelCatalog: { providers: [] },
+		});
+	},
+	play: async ({ canvasElement }) => {
+		const body = within(canvasElement.ownerDocument.body);
+		await expect(await body.findByText("GPT-4.1")).toBeInTheDocument();
+		await expect(
+			body.getByText("Model pricing is not defined"),
+		).toBeInTheDocument();
+	},
+};
+
 export const ModelDeleteConfirmation: Story = {
 	args: { section: "models" as ChatModelAdminSection },
 	beforeEach: () => {

site/src/pages/AgentsPage/ChatModelAdminPanel/ModelConfigFields.tsx

@@ -24,6 +24,10 @@ import type {
 	ModelConfigFormBuildResult,
 	ModelFormValues,
 } from "./modelConfigFormLogic";
+import {
+	getPricingPlaceholderForField,
+	pricingFieldNames,
+} from "./pricingFields";
 
 /** Sentinel value for Select components to represent "no selection". */
 const unsetSelectValue = "__unset__";
@@ -49,6 +53,11 @@ function snakeToPrettyLabel(jsonName: string): string {
  * Derive a sensible placeholder from the field schema type.
  */
 function placeholderForField(field: FieldSchema): string {
+	const pricingPlaceholder = getPricingPlaceholderForField(field.json_name);
+	if (pricingPlaceholder !== undefined) {
+		return pricingPlaceholder;
+	}
+
 	switch (field.type) {
 		case "integer":
 		case "number":
@@ -364,27 +373,25 @@ export const ModelConfigFields: FC<ModelConfigFieldsProps> = ({
 };
 
 /**
- * General model config fields (max output tokens, temperature,
- * top P, etc.) intended to be shown under an "Advanced" section.
- *
- * Fields are driven by the auto-generated schema in
- * `api/chatModelOptions`.
+ * Shared renderer for general model config fields backed by the
+ * top-level ChatModelCallConfig schema.
  */
-export const GeneralModelConfigFields: FC<ModelConfigFieldsProps> = ({
-	form,
-	fieldErrors,
-	disabled,
-}) => {
+const GeneralFieldsGroup: FC<
+	ModelConfigFieldsProps & {
+		fields: FieldSchema[];
+	}
+> = ({ form, fieldErrors, disabled, fields }) => {
 	const ctx: FieldRenderContext = { form, fieldErrors, disabled };
-	const fields = getVisibleGeneralFields();
 
 	return (
 		<>
 			{fields.map((field) => {
-				// General field keys use camelCase of the json_name directly
-				// under "config.", matching the existing form state shape:
-				// config.maxOutputTokens, config.temperature, etc.
-				const camelName = snakeToCamel(field.json_name);
+				// General field keys support nested json_name values, such as
+				// cost.input_price_per_million_tokens.
+				const camelName = field.json_name
+					.split(".")
+					.map(snakeToCamel)
+					.join(".");
 				const fieldKey = `config.${camelName}`;
 				const label = snakeToPrettyLabel(field.json_name);
 
@@ -403,3 +410,52 @@ export const GeneralModelConfigFields: FC<ModelConfigFieldsProps> = ({
 		</>
 	);
 };
+
+/**
+ * General pricing fields shown in the main form body so admins can
+ * define optional pricing metadata without opening the advanced section.
+ */
+export const PricingModelConfigFields: FC<ModelConfigFieldsProps> = ({
+	provider,
+	form,
+	fieldErrors,
+	disabled,
+}) => {
+	return (
+		<GeneralFieldsGroup
+			provider={provider}
+			form={form}
+			fieldErrors={fieldErrors}
+			disabled={disabled}
+			fields={getVisibleGeneralFields().filter(({ json_name }) =>
+				pricingFieldNames.has(json_name),
+			)}
+		/>
+	);
+};
+
+/**
+ * General model config fields (max output tokens, temperature,
+ * top P, etc.) intended to be shown under an "Advanced" section.
+ *
+ * Fields are driven by the auto-generated schema in
+ * `api/chatModelOptions`.
+ */
+export const GeneralModelConfigFields: FC<ModelConfigFieldsProps> = ({
+	provider,
+	form,
+	fieldErrors,
+	disabled,
+}) => {
+	return (
+		<GeneralFieldsGroup
+			provider={provider}
+			form={form}
+			fieldErrors={fieldErrors}
+			disabled={disabled}
+			fields={getVisibleGeneralFields().filter(
+				({ json_name }) => !pricingFieldNames.has(json_name),
+			)}
+		/>
+	);
+};

site/src/pages/AgentsPage/ChatModelAdminPanel/ModelForm.tsx

@@ -25,6 +25,7 @@ import type { ProviderState } from "./ChatModelAdminPanel";
 import {
 	GeneralModelConfigFields,
 	ModelConfigFields,
+	PricingModelConfigFields,
 } from "./ModelConfigFields";
 import {
 	buildInitialModelFormValues,
@@ -93,6 +94,7 @@ export const ModelForm: FC<ModelFormProps> = ({
 	onDeleteModel,
 }) => {
 	const isEditing = Boolean(editingModel);
+	const [showPricing, setShowPricing] = useState(false);
 	const [showAdvanced, setShowAdvanced] = useState(false);
 	const [confirmingDelete, setConfirmingDelete] = useState(false);
 
@@ -407,66 +409,102 @@ export const ModelForm: FC<ModelFormProps> = ({
 						disabled={isSaving}
 					/>
 
-					{/* Advanced — toggle */}
-					<div>
-						<button
-							type="button"
-							onClick={() => setShowAdvanced((v) => !v)}
-							className="inline-flex cursor-pointer items-center gap-1 bg-transparent border-0 p-0 text-sm font-medium text-content-secondary transition-colors hover:text-content-primary"
-						>
-							{showAdvanced ? (
-								<ChevronDownIcon className="h-4 w-4" />
-							) : (
-								<ChevronRightIcon className="h-4 w-4" />
-							)}
-							Advanced
-						</button>{" "}
-						{showAdvanced && (
-							<div className="mt-4 space-y-5">
-								<div className="grid grid-cols-2 gap-3">
-									<GeneralModelConfigFields
-										provider={selectedProviderState.provider}
-										form={form}
-										fieldErrors={modelConfigFormBuildResult.fieldErrors}
-										disabled={isSaving}
-									/>
-								</div>
-								<div className="flex flex-col gap-1.5">
-									<Label
-										htmlFor={compressionThresholdField.id}
-										className="text-sm font-medium text-content-primary"
-									>
-										Compression Threshold
-									</Label>
-									<p className="m-0 text-xs text-content-secondary">
-										Percentage at which context is compressed.
-									</p>
-									<Input
-										id={compressionThresholdField.id}
-										name={compressionThresholdField.name}
-										className={cn(
-											"h-9 text-[13px] placeholder:text-content-disabled",
-											compressionThresholdField.error &&
-												"border-content-destructive",
-										)}
-										placeholder="70"
-										value={compressionThresholdField.value}
-										onChange={compressionThresholdField.onChange}
-										onBlur={compressionThresholdField.onBlur}
-										disabled={isSaving}
-										aria-invalid={compressionThresholdField.error}
-									/>
-									{compressionThresholdField.error && (
-										<p className="m-0 text-xs text-content-destructive">
-											{compressionThresholdField.helperText}
+					<div className="space-y-5">
+						{/* Pricing — toggle */}
+						<div>
+							<button
+								type="button"
+								onClick={() => setShowPricing((v) => !v)}
+								className="inline-flex cursor-pointer items-center gap-1 bg-transparent border-0 p-0 text-sm font-medium text-content-secondary transition-colors hover:text-content-primary"
+							>
+								{showPricing ? (
+									<ChevronDownIcon className="h-4 w-4" />
+								) : (
+									<ChevronRightIcon className="h-4 w-4" />
+								)}
+								Pricing
+							</button>{" "}
+							{showPricing && (
+								<div className="mt-4 space-y-3">
+									<div>
+										<p className="m-0 text-xs text-content-secondary">
+											Optional USD pricing metadata per 1M tokens. Leave any
+											field blank to keep pricing unset and use provider or
+											profile defaults when available.
 										</p>
-									)}
+									</div>
+									<div className="grid grid-cols-1 gap-3 sm:grid-cols-2">
+										<PricingModelConfigFields
+											provider={selectedProviderState.provider}
+											form={form}
+											fieldErrors={modelConfigFormBuildResult.fieldErrors}
+											disabled={isSaving}
+										/>
+									</div>
 								</div>
-							</div>
-						)}
+							)}
+						</div>
+
+						{/* Advanced — toggle */}
+						<div>
+							<button
+								type="button"
+								onClick={() => setShowAdvanced((v) => !v)}
+								className="inline-flex cursor-pointer items-center gap-1 bg-transparent border-0 p-0 text-sm font-medium text-content-secondary transition-colors hover:text-content-primary"
+							>
+								{showAdvanced ? (
+									<ChevronDownIcon className="h-4 w-4" />
+								) : (
+									<ChevronRightIcon className="h-4 w-4" />
+								)}
+								Advanced
+							</button>{" "}
+							{showAdvanced && (
+								<div className="mt-4 space-y-5">
+									<div className="grid grid-cols-1 gap-3 sm:grid-cols-2">
+										<GeneralModelConfigFields
+											provider={selectedProviderState.provider}
+											form={form}
+											fieldErrors={modelConfigFormBuildResult.fieldErrors}
+											disabled={isSaving}
+										/>
+									</div>
+									<div className="flex flex-col gap-1.5">
+										<Label
+											htmlFor={compressionThresholdField.id}
+											className="text-sm font-medium text-content-primary"
+										>
+											Compression Threshold
+										</Label>
+										<p className="m-0 text-xs text-content-secondary">
+											Percentage at which context is compressed.
+										</p>
+										<Input
+											id={compressionThresholdField.id}
+											name={compressionThresholdField.name}
+											className={cn(
+												"h-9 text-[13px] placeholder:text-content-disabled",
+												compressionThresholdField.error &&
+													"border-content-destructive",
+											)}
+											placeholder="70"
+											value={compressionThresholdField.value}
+											onChange={compressionThresholdField.onChange}
+											onBlur={compressionThresholdField.onBlur}
+											disabled={isSaving}
+											aria-invalid={compressionThresholdField.error}
+										/>
+										{compressionThresholdField.error && (
+											<p className="m-0 text-xs text-content-destructive">
+												{compressionThresholdField.helperText}
+											</p>
+										)}
+									</div>
+								</div>
+							)}
+						</div>
 					</div>
 				</div>
-
 				{/* Footer — pushed to bottom */}
 				<div className="mt-auto pt-6">
 					<hr className="mb-4 border-0 border-t border-solid border-border" />

site/src/pages/AgentsPage/ChatModelAdminPanel/ModelsSection.test.tsx

@@ -0,0 +1,99 @@
+import { render, screen } from "@testing-library/react";
+import type * as TypesGen from "api/typesGenerated";
+import { TooltipProvider } from "components/Tooltip/Tooltip";
+import { describe, expect, it, vi } from "vitest";
+import type { ProviderState } from "./ChatModelAdminPanel";
+import { ModelsSection } from "./ModelsSection";
+
+vi.mock("./ProviderIcon", () => ({
+	ProviderIcon: ({ provider }: { provider: string }) => (
+		<div data-testid="provider-icon">{provider}</div>
+	),
+}));
+
+const providerState: ProviderState = {
+	provider: "openai",
+	label: "OpenAI",
+	providerConfig: {
+		id: "provider-config-id",
+		provider: "openai",
+		display_name: "OpenAI",
+		enabled: true,
+		has_api_key: true,
+		base_url: undefined,
+		source: "database",
+		created_at: "2025-01-01T00:00:00Z",
+		updated_at: "2025-01-01T00:00:00Z",
+	},
+	modelConfigs: [],
+	catalogModelCount: 0,
+	hasManagedAPIKey: true,
+	hasCatalogAPIKey: true,
+	hasEffectiveAPIKey: true,
+	isEnvPreset: false,
+	baseURL: "",
+};
+
+const baseModelConfig: TypesGen.ChatModelConfig = {
+	id: "model-config-id",
+	provider: "openai",
+	model: "gpt-4.1",
+	display_name: "GPT-4.1",
+	enabled: true,
+	is_default: false,
+	context_limit: 128000,
+	compression_threshold: 80,
+	created_at: "2025-01-01T00:00:00Z",
+	updated_at: "2025-01-01T00:00:00Z",
+};
+
+const renderModelsSection = (
+	modelConfigs: readonly TypesGen.ChatModelConfig[],
+) => {
+	return render(
+		<TooltipProvider>
+			<ModelsSection
+				sectionLabel="Models"
+				providerStates={[providerState]}
+				selectedProvider="openai"
+				selectedProviderState={providerState}
+				onSelectedProviderChange={vi.fn()}
+				modelConfigs={modelConfigs}
+				modelConfigsUnavailable={false}
+				isCreating={false}
+				isUpdating={false}
+				isDeleting={false}
+				onCreateModel={vi.fn()}
+				onUpdateModel={vi.fn()}
+				onDeleteModel={vi.fn()}
+			/>
+		</TooltipProvider>,
+	);
+};
+
+describe("ModelsSection", () => {
+	it("shows a warning when a model has no custom pricing configured", () => {
+		renderModelsSection([baseModelConfig]);
+
+		expect(
+			screen.getByText("Model pricing is not defined"),
+		).toBeInTheDocument();
+	});
+
+	it("hides the warning when a model has explicit zero pricing", () => {
+		renderModelsSection([
+			{
+				...baseModelConfig,
+				model_config: {
+					cost: {
+						output_price_per_million_tokens: 0,
+					},
+				},
+			},
+		]);
+
+		expect(
+			screen.queryByText("Model pricing is not defined"),
+		).not.toBeInTheDocument();
+	});
+});

site/src/pages/AgentsPage/ChatModelAdminPanel/ModelsSection.tsx

@@ -17,6 +17,7 @@ import {
 	ChevronRightIcon,
 	PlusIcon,
 	StarIcon,
+	TriangleAlertIcon,
 } from "lucide-react";
 import { type FC, type ReactNode, useState } from "react";
 import { cn } from "utils/cn";
@@ -24,6 +25,7 @@ import { SectionHeader } from "../SectionHeader";
 import type { ProviderState } from "./ChatModelAdminPanel";
 import { ModelForm } from "./ModelForm";
 import { ProviderIcon } from "./ProviderIcon";
+import { hasCustomPricing } from "./pricingFields";
 
 type ModelView =
 	| { mode: "list" }
@@ -190,79 +192,91 @@ export const ModelsSection: FC<ModelsSectionProps> = ({
 				</div>
 			) : (
 				<div className="divide-y divide-border/50">
-					{modelConfigs.map((modelConfig) => (
-						<div
-							key={modelConfig.id}
-							className="flex items-center gap-3.5 px-3 py-3"
-						>
-							{" "}
-							{/* Star for default */}
-							<Tooltip>
-								<TooltipTrigger asChild>
-									<button
-										type="button"
-										onClick={(e) => {
-											e.stopPropagation();
-											handleSetDefault(modelConfig);
-										}}
-										aria-disabled={isUpdating || modelConfig.is_default}
-										aria-label={
-											modelConfig.is_default
-												? "Default model"
-												: "Set as default model"
-										}
-										className={cn(
-											"flex h-7 w-7 shrink-0 items-center justify-center rounded-md bg-transparent border-0 p-0 transition-colors",
-											modelConfig.is_default
-												? "text-yellow-400"
-												: "cursor-pointer text-content-secondary/30 hover:text-content-secondary",
-										)}
-									>
-										<StarIcon
-											className={cn(
-												"h-4 w-4",
-												modelConfig.is_default && "fill-current",
-											)}
-										/>
-									</button>
-								</TooltipTrigger>
-								<TooltipContent side="right">
-									{modelConfig.is_default
-										? "Default model for new chats"
-										: "Set as default for new chats"}
-								</TooltipContent>
-							</Tooltip>
-							{/* Clickable row content */}
-							<button
-								type="button"
-								onClick={() => setView({ mode: "edit", model: modelConfig })}
-								className="flex min-w-0 flex-1 cursor-pointer items-center gap-3.5 bg-transparent border-0 p-0 text-left transition-colors hover:opacity-80"
+					{modelConfigs.map((modelConfig) => {
+						const showPricingWarning = !hasCustomPricing(
+							modelConfig.model_config,
+						);
+
+						return (
+							<div
+								key={modelConfig.id}
+								className="flex items-center gap-3.5 px-3 py-3"
 							>
-								<ProviderIcon
-									provider={modelConfig.provider}
-									className="h-8 w-8 shrink-0"
-								/>
-								<div className="min-w-0 flex-1">
-									<span
-										className={cn(
-											"block truncate text-[15px] font-medium",
-											modelConfig.enabled === false
-												? "text-content-secondary"
-												: "text-content-primary",
+								{" "}
+								{/* Star for default */}
+								<Tooltip>
+									<TooltipTrigger asChild>
+										<button
+											type="button"
+											onClick={(e) => {
+												e.stopPropagation();
+												handleSetDefault(modelConfig);
+											}}
+											aria-disabled={isUpdating || modelConfig.is_default}
+											aria-label={
+												modelConfig.is_default
+													? "Default model"
+													: "Set as default model"
+											}
+											className={cn(
+												"flex h-7 w-7 shrink-0 items-center justify-center rounded-md bg-transparent border-0 p-0 transition-colors",
+												modelConfig.is_default
+													? "text-yellow-400"
+													: "cursor-pointer text-content-secondary/30 hover:text-content-secondary",
+											)}
+										>
+											<StarIcon
+												className={cn(
+													"h-4 w-4",
+													modelConfig.is_default && "fill-current",
+												)}
+											/>
+										</button>
+									</TooltipTrigger>
+									<TooltipContent side="right">
+										{modelConfig.is_default
+											? "Default model for new chats"
+											: "Set as default for new chats"}
+									</TooltipContent>
+								</Tooltip>
+								{/* Clickable row content */}
+								<button
+									type="button"
+									onClick={() => setView({ mode: "edit", model: modelConfig })}
+									className="flex min-w-0 flex-1 cursor-pointer items-center gap-3.5 bg-transparent border-0 p-0 text-left transition-colors hover:opacity-80"
+								>
+									<ProviderIcon
+										provider={modelConfig.provider}
+										className="h-8 w-8 shrink-0"
+									/>
+									<div className="min-w-0 flex-1">
+										<span
+											className={cn(
+												"block truncate text-[15px] font-medium",
+												modelConfig.enabled === false
+													? "text-content-secondary"
+													: "text-content-primary",
+											)}
+										>
+											{modelConfig.display_name || modelConfig.model}
+										</span>
+										{showPricingWarning && (
+											<span className="mt-1 flex items-center gap-1 text-xs text-content-warning">
+												<TriangleAlertIcon className="h-3.5 w-3.5 shrink-0" />
+												Model pricing is not defined
+											</span>
 										)}
-									>
-										{modelConfig.display_name || modelConfig.model}
-									</span>
-								</div>
-								{modelConfig.enabled === false && (
-									<Badge size="xs" variant="warning">
-										disabled
-									</Badge>
-								)}
-								<ChevronRightIcon className="h-5 w-5 shrink-0 text-content-secondary" />
-							</button>{" "}
-						</div>
-					))}
+									</div>
+									{modelConfig.enabled === false && (
+										<Badge size="xs" variant="warning">
+											disabled
+										</Badge>
+									)}
+									<ChevronRightIcon className="h-5 w-5 shrink-0 text-content-secondary" />
+								</button>{" "}
+							</div>
+						);
+					})}
 				</div>
 			)}
 		</>

site/src/pages/AgentsPage/ChatModelAdminPanel/modelConfigFormLogic.test.ts

@@ -205,6 +205,32 @@ describe("extractModelConfigFormState", () => {
 		expect(result.frequencyPenalty).toBe("0.3");
 	});
 
+	it("extracts pricing fields", () => {
+		const model: TypesGen.ChatModelConfig = {
+			...baseChatModelConfig,
+			model_config: {
+				cost: {
+					input_price_per_million_tokens: 0.15,
+					output_price_per_million_tokens: 0.6,
+					cache_read_price_per_million_tokens: 0.03,
+					cache_write_price_per_million_tokens: 0.3,
+				},
+			},
+		};
+		const result = extractModelConfigFormState(model);
+		expect(deepGet(result, ["cost", "inputPricePerMillionTokens"])).toBe(
+			"0.15",
+		);
+		expect(deepGet(result, ["cost", "outputPricePerMillionTokens"])).toBe(
+			"0.6",
+		);
+		expect(deepGet(result, ["cost", "cacheReadPricePerMillionTokens"])).toBe(
+			"0.03",
+		);
+		expect(deepGet(result, ["cost", "cacheWritePricePerMillionTokens"])).toBe(
+			"0.3",
+		);
+	});
 	it("extracts OpenAI provider options", () => {
 		const model: TypesGen.ChatModelConfig = {
 			...baseChatModelConfig,
@@ -511,6 +537,41 @@ describe("buildModelConfigFromForm", () => {
 		});
 	});
 
+	describe("pricing fields", () => {
+		it("builds config with valid pricing fields", () => {
+			const result = buildModelConfigFromForm(
+				"openai",
+				formWith({
+					cost: {
+						inputPricePerMillionTokens: "0.15",
+						outputPricePerMillionTokens: "0.6",
+						cacheReadPricePerMillionTokens: "0.03",
+						cacheWritePricePerMillionTokens: "0.3",
+					},
+				}),
+			);
+			expect(result.fieldErrors).toEqual({});
+			expect(result.modelConfig).toMatchObject({
+				cost: {
+					input_price_per_million_tokens: 0.15,
+					output_price_per_million_tokens: 0.6,
+					cache_read_price_per_million_tokens: 0.03,
+					cache_write_price_per_million_tokens: 0.3,
+				},
+			});
+		});
+
+		it("reports error for negative pricing fields", () => {
+			const result = buildModelConfigFromForm(
+				"openai",
+				formWith({ cost: { inputPricePerMillionTokens: "-0.5" } }),
+			);
+			expect(result.fieldErrors["cost.inputPricePerMillionTokens"]).toContain(
+				"must be zero or greater",
+			);
+			expect(result.modelConfig).toBeUndefined();
+		});
+	});
 	describe("OpenAI / Azure provider", () => {
 		it("builds OpenAI provider options with reasoning effort", () => {
 			const result = buildModelConfigFromForm(

site/src/pages/AgentsPage/ChatModelAdminPanel/modelConfigFormLogic.ts

@@ -8,6 +8,7 @@ import {
 } from "api/chatModelOptions";
 import type * as TypesGen from "api/typesGenerated";
 import * as Yup from "yup";
+import { pricingFieldNames } from "./pricingFields";
 
 // ── Preserved public types ─────────────────────────────────────
 
@@ -155,10 +156,10 @@ function buildEmptyProviderState(provider: string): Record<string, unknown> {
 export const emptyModelConfigFormState: ModelConfigFormState = (() => {
 	const state: ModelConfigFormState = {};
 
-	// General fields (e.g. maxOutputTokens, temperature).
+	// General fields (e.g. maxOutputTokens, cost.inputPricePerMillionTokens).
 	for (const field of getGeneralFields()) {
-		const key = snakeToCamel(field.json_name);
-		state[key] = "";
+		const camelSegments = field.json_name.split(".").map(snakeToCamel);
+		deepSet(state, camelSegments, "");
 	}
 
 	// Provider sub-objects.
@@ -181,12 +182,12 @@ export const extractModelConfigFormState = (
 
 	const state: ModelConfigFormState = {};
 
-	// General fields — read from the top level of the API config
-	// using the snake_case json_name.
+	// General fields may be nested (for example, cost.input_price_per_million_tokens).
 	for (const field of getGeneralFields()) {
-		const camelKey = snakeToCamel(field.json_name);
-		const apiValue = (config as Record<string, unknown>)[field.json_name];
-		state[camelKey] = toFormString(apiValue);
+		const snakeSegments = field.json_name.split(".");
+		const camelSegments = snakeSegments.map(snakeToCamel);
+		const apiValue = deepGet(config, snakeSegments);
+		deepSet(state, camelSegments, toFormString(apiValue));
 	}
 
 	// Provider sub-objects.
@@ -233,6 +234,25 @@ export const buildInitialModelFormValues = (
 		: structuredClone(emptyModelConfigFormState),
 });
 
+function isNonNegativePricingField(field: FieldSchema): boolean {
+	return pricingFieldNames.has(field.json_name);
+}
+
+function isValidOptionalNumber(
+	value: string | undefined,
+	minimum?: number,
+): boolean {
+	const trimmed = value?.trim();
+	if (!trimmed) {
+		return true;
+	}
+
+	const parsed = Number(trimmed);
+	return (
+		Number.isFinite(parsed) && (minimum === undefined || parsed >= minimum)
+	);
+}
+
 // ── Schema-driven Yup validation ───────────────────────────────
 
 /**
@@ -255,16 +275,16 @@ function yupTestForField(field: FieldSchema): Yup.StringSchema {
 				},
 			);
 
-		case "number":
-			return Yup.string().test(
-				"optional-number",
-				`${label} must be a valid number.`,
-				(value) => {
-					const trimmed = value?.trim();
-					if (!trimmed) return true;
-					return Number.isFinite(Number(trimmed));
-				},
+		case "number": {
+			const minimum = isNonNegativePricingField(field) ? 0 : undefined;
+			const errorMessage =
+				minimum === 0
+					? `${label} must be zero or greater.`
+					: `${label} must be a valid number.`;
+			return Yup.string().test("optional-number", errorMessage, (value) =>
+				isValidOptionalNumber(value, minimum),
 			);
+		}
 
 		case "boolean":
 			return Yup.string().test(
@@ -472,11 +492,12 @@ export const buildModelConfigFromForm = (
 	const modelConfig: Record<string, unknown> = {};
 
 	for (const field of getGeneralFields()) {
-		const formValue = form[snakeToCamel(field.json_name)];
+		const camelSegments = field.json_name.split(".").map(snakeToCamel);
+		const formValue = deepGet(form, camelSegments);
 		if (typeof formValue !== "string") continue;
 		const converted = convertFormValue(formValue, field);
 		if (converted !== undefined) {
-			modelConfig[field.json_name] = converted;
+			deepSet(modelConfig, field.json_name.split("."), converted);
 		}
 	}
 

site/src/pages/AgentsPage/ChatModelAdminPanel/pricingFields.test.ts

@@ -0,0 +1,42 @@
+import type * as TypesGen from "api/typesGenerated";
+import { describe, expect, it } from "vitest";
+import {
+	getDefaultPricingForField,
+	getPricingPlaceholderForField,
+	hasCustomPricing,
+	pricingFieldNameList,
+} from "./pricingFields";
+
+describe("pricingFields", () => {
+	it("uses $0 defaults for every pricing field", () => {
+		for (const fieldName of pricingFieldNameList) {
+			expect(getDefaultPricingForField(fieldName)).toBe(0);
+			expect(getPricingPlaceholderForField(fieldName)).toBe("0");
+		}
+	});
+
+	it("treats missing pricing as undefined pricing", () => {
+		expect(hasCustomPricing()).toBe(false);
+	});
+
+	it("treats explicit zero pricing as custom pricing", () => {
+		expect(
+			hasCustomPricing({
+				cost: {
+					input_price_per_million_tokens: 0,
+					output_price_per_million_tokens: 0,
+				},
+			} satisfies TypesGen.ChatModelCallConfig),
+		).toBe(true);
+	});
+
+	it("detects custom pricing when any pricing field is greater than zero", () => {
+		expect(
+			hasCustomPricing({
+				cost: {
+					cache_write_price_per_million_tokens: 0.25,
+				},
+			} satisfies TypesGen.ChatModelCallConfig),
+		).toBe(true);
+	});
+});

site/src/pages/AgentsPage/ChatModelAdminPanel/pricingFields.ts

@@ -0,0 +1,65 @@
+import type * as TypesGen from "api/typesGenerated";
+
+// Single source of truth for the model config fields that belong in the
+// Pricing section and require non-negative validation.
+export const pricingFieldNameList = [
+	"cost.input_price_per_million_tokens",
+	"cost.output_price_per_million_tokens",
+	"cost.cache_read_price_per_million_tokens",
+	"cost.cache_write_price_per_million_tokens",
+] as const;
+
+export const pricingFieldNames = new Set<string>(pricingFieldNameList);
+
+type PricingFieldName = (typeof pricingFieldNameList)[number];
+
+export const defaultPricingByFieldName = {
+	"cost.input_price_per_million_tokens": 0,
+	"cost.output_price_per_million_tokens": 0,
+	"cost.cache_read_price_per_million_tokens": 0,
+	"cost.cache_write_price_per_million_tokens": 0,
+} as const satisfies Record<PricingFieldName, number>;
+
+export const pricingPlaceholderByFieldName = {
+	"cost.input_price_per_million_tokens": "0",
+	"cost.output_price_per_million_tokens": "0",
+	"cost.cache_read_price_per_million_tokens": "0",
+	"cost.cache_write_price_per_million_tokens": "0",
+} as const satisfies Record<PricingFieldName, string>;
+
+export const getDefaultPricingForField = (
+	fieldName: string,
+): number | undefined =>
+	defaultPricingByFieldName[
+		fieldName as keyof typeof defaultPricingByFieldName
+	];
+
+export const getPricingPlaceholderForField = (
+	fieldName: string,
+): string | undefined =>
+	pricingPlaceholderByFieldName[
+		fieldName as keyof typeof pricingPlaceholderByFieldName
+	];
+
+const getNestedValue = (value: unknown, path: readonly string[]): unknown => {
+	let current = value;
+	for (const segment of path) {
+		if (
+			current === undefined ||
+			current === null ||
+			typeof current !== "object"
+		) {
+			return undefined;
+		}
+		current = (current as Record<string, unknown>)[segment];
+	}
+	return current;
+};
+
+export const hasCustomPricing = (
+	modelConfig?: TypesGen.ChatModelCallConfig,
+): boolean =>
+	pricingFieldNameList.some(
+		(fieldName) =>
+			getNestedValue(modelConfig, fieldName.split(".")) !== undefined,
+	);