add step finish part

4 files changed, 149 insertions, 18 deletions

diff --git a/packages/opencode/src/session/index.ts b/packages/opencode/src/session/index.ts
index 6ca120512..d1744d0ab 100644
--- a/packages/opencode/src/session/index.ts
+++ b/packages/opencode/src/session/index.ts
@@ -721,6 +721,11 @@ export namespace Session {
             const usage = getUsage(model.info, value.usage, value.providerMetadata)
             next.cost += usage.cost
             next.tokens = usage.tokens
+            next.parts.push({
+              type: "step-finish",
+              tokens: usage.tokens,
+              cost: usage.cost,
+            })
             break
 
           case "text-start":
diff --git a/packages/opencode/src/session/message-v2.ts b/packages/opencode/src/session/message-v2.ts
index fba34f4c0..aadc1a5e2 100644
--- a/packages/opencode/src/session/message-v2.ts
+++ b/packages/opencode/src/session/message-v2.ts
@@ -116,6 +116,25 @@ export namespace MessageV2 {
     })
   export type StepStartPart = z.infer<typeof StepStartPart>
 
+  export const StepFinishPart = z
+    .object({
+      type: z.literal("step-finish"),
+      cost: z.number(),
+      tokens: z.object({
+        input: z.number(),
+        output: z.number(),
+        reasoning: z.number(),
+        cache: z.object({
+          read: z.number(),
+          write: z.number(),
+        }),
+      }),
+    })
+    .openapi({
+      ref: "StepFinishPart",
+    })
+  export type StepFinishPart = z.infer<typeof StepFinishPart>
+
   const Base = z.object({
     id: z.string(),
     sessionID: z.string(),
@@ -137,9 +156,11 @@ export namespace MessageV2 {
   })
   export type User = z.infer<typeof User>
 
-  export const AssistantPart = z.discriminatedUnion("type", [TextPart, ToolPart, StepStartPart]).openapi({
-    ref: "AssistantMessagePart",
-  })
+  export const AssistantPart = z
+    .discriminatedUnion("type", [TextPart, ToolPart, StepStartPart, StepFinishPart])
+    .openapi({
+      ref: "AssistantMessagePart",
+    })
   export type AssistantPart = z.infer<typeof AssistantPart>
 
   export const Assistant = Base.extend({
@@ -164,8 +185,8 @@ export namespace MessageV2 {
       cwd: z.string(),
       root: z.string(),
     }),
-    cost: z.number(),
     summary: z.boolean().optional(),
+    cost: z.number(),
     tokens: z.object({
       input: z.number(),
       output: z.number(),
diff --git a/packages/tui/sdk/.stats.yml b/packages/tui/sdk/.stats.yml
index 225a0e490..4449c4d95 100644
--- a/packages/tui/sdk/.stats.yml
+++ b/packages/tui/sdk/.stats.yml
@@ -1,4 +1,4 @@
 configured_endpoints: 22
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/opencode%2Fopencode-37247433660e125f9a79ff173d8007f13192d28a40f4e599e002446a6ed0c128.yml
-openapi_spec_hash: 8095ebe2d88259381a58e7b0c87244c4
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/opencode%2Fopencode-eb25bb3673f94d0e98a7036e2a2b0ed7ad63d1598665f2d5e091ec0835273798.yml
+openapi_spec_hash: 62f6a8a06aaa4f4ae13e85d56652724f
 config_hash: 589ec6a935a43a3c49a325ece86cbda2
diff --git a/packages/tui/sdk/session.go b/packages/tui/sdk/session.go
index 1f19b97f5..6321d1ff6 100644
--- a/packages/tui/sdk/session.go
+++ b/packages/tui/sdk/session.go
@@ -438,13 +438,17 @@ func (r AssistantMessageErrorName) IsKnown() bool {
 type AssistantMessagePart struct {
 	Type AssistantMessagePartType `json:"type,required"`
 	ID   string                   `json:"id"`
+	Cost float64                  `json:"cost"`
 	// This field can have the runtime type of [ToolPartState].
-	State     interface{}              `json:"state"`
-	Synthetic bool                     `json:"synthetic"`
-	Text      string                   `json:"text"`
-	Tool      string                   `json:"tool"`
-	JSON      assistantMessagePartJSON `json:"-"`
-	union     AssistantMessagePartUnion
+	State     interface{} `json:"state"`
+	Synthetic bool        `json:"synthetic"`
+	Text      string      `json:"text"`
+	// This field can have the runtime type of
+	// [AssistantMessagePartStepFinishPartTokens].
+	Tokens interface{}              `json:"tokens"`
+	Tool   string                   `json:"tool"`
+	JSON   assistantMessagePartJSON `json:"-"`
+	union  AssistantMessagePartUnion
 }
 
 // assistantMessagePartJSON contains the JSON metadata for the struct
@@ -452,9 +456,11 @@ type AssistantMessagePart struct {
 type assistantMessagePartJSON struct {
 	Type        apijson.Field
 	ID          apijson.Field
+	Cost        apijson.Field
 	State       apijson.Field
 	Synthetic   apijson.Field
 	Text        apijson.Field
+	Tokens      apijson.Field
 	Tool        apijson.Field
 	raw         string
 	ExtraFields map[string]apijson.Field
@@ -476,12 +482,14 @@ func (r *AssistantMessagePart) UnmarshalJSON(data []byte) (err error) {
 // AsUnion returns a [AssistantMessagePartUnion] interface which you can cast to
 // the specific types for more type safety.
 //
-// Possible runtime types of the union are [TextPart], [ToolPart], [StepStartPart].
+// Possible runtime types of the union are [TextPart], [ToolPart], [StepStartPart],
+// [AssistantMessagePartStepFinishPart].
 func (r AssistantMessagePart) AsUnion() AssistantMessagePartUnion {
 	return r.union
 }
 
-// Union satisfied by [TextPart], [ToolPart] or [StepStartPart].
+// Union satisfied by [TextPart], [ToolPart], [StepStartPart] or
+// [AssistantMessagePartStepFinishPart].
 type AssistantMessagePartUnion interface {
 	implementsAssistantMessagePart()
 }
@@ -505,20 +513,117 @@ func init() {
 			Type:               reflect.TypeOf(StepStartPart{}),
 			DiscriminatorValue: "step-start",
 		},
+		apijson.UnionVariant{
+			TypeFilter:         gjson.JSON,
+			Type:               reflect.TypeOf(AssistantMessagePartStepFinishPart{}),
+			DiscriminatorValue: "step-finish",
+		},
 	)
 }
 
+type AssistantMessagePartStepFinishPart struct {
+	Cost   float64                                  `json:"cost,required"`
+	Tokens AssistantMessagePartStepFinishPartTokens `json:"tokens,required"`
+	Type   AssistantMessagePartStepFinishPartType   `json:"type,required"`
+	JSON   assistantMessagePartStepFinishPartJSON   `json:"-"`
+}
+
+// assistantMessagePartStepFinishPartJSON contains the JSON metadata for the struct
+// [AssistantMessagePartStepFinishPart]
+type assistantMessagePartStepFinishPartJSON struct {
+	Cost        apijson.Field
+	Tokens      apijson.Field
+	Type        apijson.Field
+	raw         string
+	ExtraFields map[string]apijson.Field
+}
+
+func (r *AssistantMessagePartStepFinishPart) UnmarshalJSON(data []byte) (err error) {
+	return apijson.UnmarshalRoot(data, r)
+}
+
+func (r assistantMessagePartStepFinishPartJSON) RawJSON() string {
+	return r.raw
+}
+
+func (r AssistantMessagePartStepFinishPart) implementsAssistantMessagePart() {}
+
+type AssistantMessagePartStepFinishPartTokens struct {
+	Cache     AssistantMessagePartStepFinishPartTokensCache `json:"cache,required"`
+	Input     float64                                       `json:"input,required"`
+	Output    float64                                       `json:"output,required"`
+	Reasoning float64                                       `json:"reasoning,required"`
+	JSON      assistantMessagePartStepFinishPartTokensJSON  `json:"-"`
+}
+
+// assistantMessagePartStepFinishPartTokensJSON contains the JSON metadata for the
+// struct [AssistantMessagePartStepFinishPartTokens]
+type assistantMessagePartStepFinishPartTokensJSON struct {
+	Cache       apijson.Field
+	Input       apijson.Field
+	Output      apijson.Field
+	Reasoning   apijson.Field
+	raw         string
+	ExtraFields map[string]apijson.Field
+}
+
+func (r *AssistantMessagePartStepFinishPartTokens) UnmarshalJSON(data []byte) (err error) {
+	return apijson.UnmarshalRoot(data, r)
+}
+
+func (r assistantMessagePartStepFinishPartTokensJSON) RawJSON() string {
+	return r.raw
+}
+
+type AssistantMessagePartStepFinishPartTokensCache struct {
+	Read  float64                                           `json:"read,required"`
+	Write float64                                           `json:"write,required"`
+	JSON  assistantMessagePartStepFinishPartTokensCacheJSON `json:"-"`
+}
+
+// assistantMessagePartStepFinishPartTokensCacheJSON contains the JSON metadata for
+// the struct [AssistantMessagePartStepFinishPartTokensCache]
+type assistantMessagePartStepFinishPartTokensCacheJSON struct {
+	Read        apijson.Field
+	Write       apijson.Field
+	raw         string
+	ExtraFields map[string]apijson.Field
+}
+
+func (r *AssistantMessagePartStepFinishPartTokensCache) UnmarshalJSON(data []byte) (err error) {
+	return apijson.UnmarshalRoot(data, r)
+}
+
+func (r assistantMessagePartStepFinishPartTokensCacheJSON) RawJSON() string {
+	return r.raw
+}
+
+type AssistantMessagePartStepFinishPartType string
+
+const (
+	AssistantMessagePartStepFinishPartTypeStepFinish AssistantMessagePartStepFinishPartType = "step-finish"
+)
+
+func (r AssistantMessagePartStepFinishPartType) IsKnown() bool {
+	switch r {
+	case AssistantMessagePartStepFinishPartTypeStepFinish:
+		return true
+	}
+	return false
+}
+
 type AssistantMessagePartType string
 
 const (
-	AssistantMessagePartTypeText      AssistantMessagePartType = "text"
-	AssistantMessagePartTypeTool      AssistantMessagePartType = "tool"
-	AssistantMessagePartTypeStepStart AssistantMessagePartType = "step-start"
+	AssistantMessagePartTypeText       AssistantMessagePartType = "text"
+	AssistantMessagePartTypeTool       AssistantMessagePartType = "tool"
+	AssistantMessagePartTypeStepStart  AssistantMessagePartType = "step-start"
+	AssistantMessagePartTypeStepFinish AssistantMessagePartType = "step-finish"
 )
 
 func (r AssistantMessagePartType) IsKnown() bool {
 	switch r {
-	case AssistantMessagePartTypeText, AssistantMessagePartTypeTool, AssistantMessagePartTypeStepStart:
+	case AssistantMessagePartTypeText, AssistantMessagePartTypeTool, AssistantMessagePartTypeStepStart, AssistantMessagePartTypeStepFinish:
 		return true
 	}
 	return false