coder · ibetitsmike · Aug 3, 2026 · Jul 29, 2026 · Jul 29, 2026 · Jul 29, 2026
diff --git a/coderd/apidoc/docs.go b/coderd/apidoc/docs.go
diff --git a/coderd/apidoc/swagger.json b/coderd/apidoc/swagger.json
diff --git a/coderd/exp_chats_hooks_test.go b/coderd/exp_chats_hooks_test.go
@@ -309,17 +309,26 @@ func TestChatLifecycleHooksWorkedExample(t *testing.T) {
 
 	messages, err := client.GetChatMessages(ctx, chat.ID, nil)
 	require.NoError(t, err)
-	var allowedCall *codersdk.ChatMessagePart
+	var allowedCall, deniedCall *codersdk.ChatMessagePart
 	for _, message := range messages.Messages {
 		for i := range message.Content {
 			part := &message.Content[i]
-			if part.Type == codersdk.ChatMessagePartTypeToolCall && part.ToolCallID == allowedToolCallID {
+			if part.Type != codersdk.ChatMessagePartTypeToolCall {
+				continue
+			}
+			switch part.ToolCallID {
+			case allowedToolCallID:
 				allowedCall = part
+			case deniedToolCallID:
+				deniedCall = part
 			}
 		}
 	}
 	require.NotNil(t, allowedCall)
 	require.JSONEq(t, `{"query":"public documentation"}`, string(allowedCall.Args))
+	require.True(t, allowedCall.HookRewritten)
+	require.NotNil(t, deniedCall)
+	require.False(t, deniedCall.HookRewritten)
 
 	err = client.SubmitToolResults(ctx, chat.ID, codersdk.SubmitToolResultsRequest{
 		Results: []codersdk.ToolResult{{
@@ -343,7 +352,7 @@ func TestChatLifecycleHooksWorkedExample(t *testing.T) {
 			continue
 		}
 		for _, part := range message.Content {
-			if part.Type == codersdk.ChatMessagePartTypeText && part.Text == "Search result approved by policy." {
+			if part.Type == codersdk.ChatMessagePartTypeHookNotice && part.Text == "Search result approved by policy." {
 				foundPostToolNotice = true
 			}
 		}
@@ -410,19 +419,20 @@ func TestChatHooksFileLinksAfterPromptOverride(t *testing.T) {
 		return resp.ID
 	}
 
-	redactedFile := uploadFile("redacted.png")
+	createFile := uploadFile("create.png")
 	chat, err := client.CreateChat(ctx, codersdk.CreateChatRequest{
 		OrganizationID: user.OrganizationID,
 		ModelConfigID:  &model.ID,
 		Content: []codersdk.ChatInputPart{
 			{Type: codersdk.ChatInputPartTypeText, Text: "REDACTME create"},
-			{Type: codersdk.ChatInputPartTypeFile, FileID: redactedFile},
+			{Type: codersdk.ChatInputPartTypeFile, FileID: createFile},
 		},
 	})
 	require.NoError(t, err)
 	created, err := client.GetChat(ctx, chat.ID)
 	require.NoError(t, err)
-	require.Empty(t, created.Files, "overridden create must not link dropped attachments")
+	require.Len(t, created.Files, 1, "an overridden create must keep linking its attachments")
+	require.Equal(t, createFile, created.Files[0].ID)
 
 	coderdtest.WaitForChatSettled(ctx, t, api, chat.ID)
 
@@ -437,23 +447,37 @@ func TestChatHooksFileLinksAfterPromptOverride(t *testing.T) {
 	require.False(t, sendResp.Queued)
 	afterSend, err := client.GetChat(ctx, chat.ID)
 	require.NoError(t, err)
-	require.Len(t, afterSend.Files, 1)
-	require.Equal(t, keptFile, afterSend.Files[0].ID)
+	require.Len(t, afterSend.Files, 2)
+	require.ElementsMatch(t, []uuid.UUID{createFile, keptFile}, []uuid.UUID{afterSend.Files[0].ID, afterSend.Files[1].ID})
 
 	coderdtest.WaitForChatSettled(ctx, t, api, chat.ID)
 
-	droppedFile := uploadFile("dropped.png")
-	_, err = client.CreateChatMessage(ctx, chat.ID, codersdk.CreateChatMessageRequest{
+	overriddenFile := uploadFile("overridden.png")
+	sendResp, err = client.CreateChatMessage(ctx, chat.ID, codersdk.CreateChatMessageRequest{
 		Content: []codersdk.ChatInputPart{
+			{Type: codersdk.ChatInputPartTypeFileReference, FileName: "main.go", StartLine: 1, EndLine: 3, Content: "package main"},
 			{Type: codersdk.ChatInputPartTypeText, Text: "REDACTME send"},
-			{Type: codersdk.ChatInputPartTypeFile, FileID: droppedFile},
+			{Type: codersdk.ChatInputPartTypeFile, FileID: overriddenFile},
 		},
 	})
 	require.NoError(t, err)
+	require.False(t, sendResp.Queued)
 	afterOverride, err := client.GetChat(ctx, chat.ID)
 	require.NoError(t, err)
-	require.Len(t, afterOverride.Files, 1, "overridden send must not link dropped attachments")
-	require.Equal(t, keptFile, afterOverride.Files[0].ID)
+	require.Len(t, afterOverride.Files, 3, "an overridden send must keep linking its attachments")
+	require.ElementsMatch(t, []uuid.UUID{createFile, keptFile, overriddenFile}, []uuid.UUID{
+		afterOverride.Files[0].ID,
+		afterOverride.Files[1].ID,
+		afterOverride.Files[2].ID,
+	})
+
+	require.NotNil(t, sendResp.Message)
+	require.Equal(t, codersdk.ChatMessageRoleUser, sendResp.Message.Role)
+	require.Equal(t, []codersdk.ChatMessagePart{
+		codersdk.ChatMessageFileReference("main.go", 1, 3, "package main"),
+		codersdk.ChatMessageText("redacted"),
+		codersdk.ChatMessageFile(overriddenFile, "image/png", "overridden.png"),
+	}, sendResp.Message.Content)
 }
 
 func TestChatHookNoticeMessagesInResponses(t *testing.T) {
@@ -576,7 +600,7 @@ func TestChatHookNoticeMessagesInResponses(t *testing.T) {
 			continue
 		}
 		for _, part := range message.Content {
-			if part.Type == codersdk.ChatMessagePartTypeText && part.Text == "session notice" {
+			if part.Type == codersdk.ChatMessagePartTypeHookNotice && part.Text == "session notice" {
 				sessionNoticeFound = true
 			}
 		}

diff --git a/coderd/x/chatd/chathooks/effects.go b/coderd/x/chatd/chathooks/effects.go
@@ -36,7 +36,10 @@ func EventMessages(result *Result, modelConfigID uuid.UUID) ([]chatstate.Message
 		})
 	}
 	if result.GetUserMessage() != "" {
-		content, err := chatprompt.MarshalParts([]codersdk.ChatMessagePart{codersdk.ChatMessageText(result.UserMessage)})
+		content, err := chatprompt.MarshalParts([]codersdk.ChatMessagePart{{
+			Type: codersdk.ChatMessagePartTypeHookNotice,
+			Text: result.UserMessage,
+		}})
 		if err != nil {
 			return nil, xerrors.Errorf("marshal hook user message: %w", err)
 		}
@@ -156,6 +159,25 @@ func UserPromptParts(result *Result) []codersdk.ChatMessagePart {
 	return parts
 }
 
+func applyPromptOverride(parts []codersdk.ChatMessagePart, override string) []codersdk.ChatMessagePart {
+	userParts := make([]codersdk.ChatMessagePart, 0, len(parts)+1)
+	replaced := false
+	for _, part := range parts {
+		if part.Type != codersdk.ChatMessagePartTypeText {
+			userParts = append(userParts, part)
+			continue
+		}
+		if !replaced {
+			userParts = append(userParts, codersdk.ChatMessageText(override))
+			replaced = true
+		}
+	}
+	if !replaced {
+		userParts = append(userParts, codersdk.ChatMessageText(override))
+	}
+	return userParts
+}
+
 // ComposeUserPromptContent applies a user_prompt_submit result to the
 // submitted parts. The merge order is fixed: override-or-original user
 // parts first, then hook-context, then hook-notice. The composite
@@ -167,7 +189,7 @@ func ComposeUserPromptContent(parts []codersdk.ChatMessagePart, result *Result)
 	}
 	userParts := parts
 	if overridden {
-		userParts = []codersdk.ChatMessagePart{codersdk.ChatMessageText(override)}
+		userParts = applyPromptOverride(parts, override)
 	}
 	hookParts := UserPromptParts(result)
 	if len(hookParts) == 0 {

diff --git a/coderd/x/chatd/chathooks/hooks_internal_test.go b/coderd/x/chatd/chathooks/hooks_internal_test.go
@@ -18,6 +18,7 @@ import (
 	"github.com/coder/coder/v2/coderd/database/dbgen"
 	"github.com/coder/coder/v2/coderd/database/dbtestutil"
 	"github.com/coder/coder/v2/coderd/x/agenthooks/dispatch"
+	"github.com/coder/coder/v2/codersdk"
 	"github.com/coder/coder/v2/codersdk/x/agenthooks"
 	"github.com/coder/coder/v2/testutil"
 )
@@ -273,3 +274,64 @@ func TestEventMessagesSkipsBlankModelContext(t *testing.T) {
 	require.Len(t, messages, 1)
 	require.Equal(t, database.ChatMessageVisibilityModel, messages[0].Visibility)
 }
+
+func TestComposeUserPromptContentOverride(t *testing.T) {
+	t.Parallel()
+
+	text := codersdk.ChatMessageText("original")
+	reference := codersdk.ChatMessageFileReference("main.go", 1, 3, "package main")
+	upload := codersdk.ChatMessageFile(uuid.New(), "image/png", "shot.png")
+	override := &Result{InputOverride: json.RawMessage(`{"prompt":"replacement"}`)}
+
+	t.Run("ReplacesTextInPlaceAndKeepsAttachments", func(t *testing.T) {
+		t.Parallel()
+
+		parts, overridden, err := ComposeUserPromptContent([]codersdk.ChatMessagePart{reference, text, upload}, override)
+		require.NoError(t, err)
+		require.True(t, overridden)
+		require.Equal(t, []codersdk.ChatMessagePart{
+			reference,
+			codersdk.ChatMessageText("replacement"),
+			upload,
+		}, parts)
+	})
+
+	t.Run("CollapsesEveryTextPart", func(t *testing.T) {
+		t.Parallel()
+
+		parts, overridden, err := ComposeUserPromptContent([]codersdk.ChatMessagePart{
+			text,
+			upload,
+			codersdk.ChatMessageText("trailing"),
+		}, override)
+		require.NoError(t, err)
+		require.True(t, overridden)
+		require.Equal(t, []codersdk.ChatMessagePart{
+			codersdk.ChatMessageText("replacement"),
+			upload,
+		}, parts)
+	})
+
+	t.Run("AppendsWhenSubmissionHasNoText", func(t *testing.T) {
+		t.Parallel()
+
+		parts, overridden, err := ComposeUserPromptContent([]codersdk.ChatMessagePart{upload}, override)
+		require.NoError(t, err)
+		require.True(t, overridden)
+		require.Equal(t, []codersdk.ChatMessagePart{upload, codersdk.ChatMessageText("replacement")}, parts)
+	})
+
+	t.Run("KeepsSubmittedPartsWithoutOverride", func(t *testing.T) {
+		t.Parallel()
+
+		submitted := []codersdk.ChatMessagePart{text, upload}
+		parts, overridden, err := ComposeUserPromptContent(submitted, &Result{UserMessage: "notice"})
+		require.NoError(t, err)
+		require.False(t, overridden)
+		require.Equal(t, []codersdk.ChatMessagePart{
+			text,
+			upload,
+			{Type: codersdk.ChatMessagePartTypeHookNotice, Text: "notice"},
+		}, parts)
+	})
+}
diff --git a/coderd/x/chatd/generation.go b/coderd/x/chatd/generation.go
@@ -748,12 +748,13 @@ func (s *taskStarter) generateAssistant(
 	}
 	outcome.Step.Content = chathooks.ApplyAdmittedToolCalls(outcome.Step.Content, preflight)
 	messages, err := buildCommitStepMessages(buildCommitStepMessagesInput{
-		modelConfigID:      prepared.ModelConfigID,
-		modelCallConfig:    prepared.ModelConfig,
-		step:               stepDataFromPersisted(outcome.Step),
-		toolNameToConfigID: prepared.ToolNameToConfigID,
-		logger:             s.opts.Logger,
-		contentVersion:     chatprompt.CurrentContentVersion,
+		modelConfigID:          prepared.ModelConfigID,
+		modelCallConfig:        prepared.ModelConfig,
+		step:                   stepDataFromPersisted(outcome.Step),
+		toolNameToConfigID:     prepared.ToolNameToConfigID,
+		logger:                 s.opts.Logger,
+		contentVersion:         chatprompt.CurrentContentVersion,
+		hookRewrittenToolCalls: preflight.Overrides,
 	})
 	if err != nil {
 		return s.finishGenerationError(ctx, machine, input, err, requireGenerationAttempt(attempt.number))

diff --git a/coderd/x/chatd/hooks_test.go b/coderd/x/chatd/hooks_test.go
@@ -74,6 +74,7 @@ func TestSendMessageUserPromptSubmitHook(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, []codersdk.ChatMessagePart{
 			codersdk.ChatMessageText("after"),
+			codersdk.ChatMessageFileReference("main.go", 1, 3, "package main"),
 			{Type: codersdk.ChatMessagePartTypeHookContext, Text: "model only"},
 			{Type: codersdk.ChatMessagePartTypeHookNotice, Text: "user only"},
 		}, parts)
@@ -475,17 +476,25 @@ func TestEditMessageUserPromptSubmitHook(t *testing.T) {
 	t.Cleanup(consumer.Close)
 	server := newHookTestServer(t, db, ps, consumer)
 
+	upload := codersdk.ChatMessageFile(uuid.New(), "image/png", "edited.png")
+	reference := codersdk.ChatMessageFileReference("main.go", 1, 3, "package main")
 	result, err := server.EditMessage(ctx, chatd.EditMessageOptions{
 		ChatID:          chat.ID,
 		CreatedBy:       user.ID,
 		EditedMessageID: inserted[0].ID,
-		Content:         []codersdk.ChatMessagePart{codersdk.ChatMessageText("edited original")},
+		Content: []codersdk.ChatMessagePart{
+			reference,
+			codersdk.ChatMessageText("edited original"),
+			upload,
+		},
 	})
 	require.NoError(t, err)
 	parts, err := chatprompt.ParseContent(result.Message)
 	require.NoError(t, err)
 	require.Equal(t, []codersdk.ChatMessagePart{
+		reference,
 		codersdk.ChatMessageText("edited override"),
+		upload,
 		{Type: codersdk.ChatMessagePartTypeHookContext, Text: "edit context"},
 		{Type: codersdk.ChatMessagePartTypeHookNotice, Text: "edit notice"},
 	}, parts)

diff --git a/coderd/x/chatd/message_conversion.go b/coderd/x/chatd/message_conversion.go
@@ -28,12 +28,13 @@ import (
 const interruptedToolResultErrorMessage = "tool call was interrupted before it produced a result"
 
 type buildCommitStepMessagesInput struct {
-	modelConfigID      uuid.UUID
-	modelCallConfig    codersdk.ChatModelCallConfig
-	step               stepData
-	toolNameToConfigID map[string]uuid.UUID
-	logger             slog.Logger
-	contentVersion     int16
+	modelConfigID          uuid.UUID
+	modelCallConfig        codersdk.ChatModelCallConfig
+	step                   stepData
+	toolNameToConfigID     map[string]uuid.UUID
+	logger                 slog.Logger
+	contentVersion         int16
+	hookRewrittenToolCalls map[string]json.RawMessage
 }
 
 type stepMessagesForCommit struct {
@@ -51,7 +52,7 @@ func buildCommitStepMessages(input buildCommitStepMessagesInput) (stepMessagesFo
 	}
 
 	assistantBlocks, toolResults := splitStepContent(input.step.Content)
-	assistantParts := buildAssistantParts(input.logger, assistantBlocks, toolResults, input.step, input.toolNameToConfigID)
+	assistantParts := buildAssistantParts(input.logger, assistantBlocks, toolResults, input.step, input.toolNameToConfigID, input.hookRewrittenToolCalls)
 
 	messages := make([]chatstate.Message, 0, 1+len(toolResults))
 	if len(assistantParts) > 0 {
@@ -112,6 +113,7 @@ func buildAssistantParts(
 	toolResults []fantasy.ToolResultContent,
 	step stepData,
 	toolNameToConfigID map[string]uuid.UUID,
+	hookRewrittenToolCalls map[string]json.RawMessage,
 ) []codersdk.ChatMessagePart {
 	parts := make([]codersdk.ChatMessagePart, 0, len(assistantBlocks)+len(toolResults))
 	reasoningIdx := 0
@@ -125,6 +127,11 @@ func buildAssistantParts(
 					part.CreatedAt = &ts
 				}
 			}
+			// Hooks never see provider-executed calls, so such a call must not
+			// inherit attribution from an ordinary call that reused its ID.
+			if part.ToolCallID != "" && !part.ProviderExecuted {
+				_, part.HookRewritten = hookRewrittenToolCalls[part.ToolCallID]
+			}
 		case codersdk.ChatMessagePartTypeToolResult:
 			if part.ToolCallID != "" && step.ToolResultCreatedAt != nil {
 				if ts, ok := step.ToolResultCreatedAt[part.ToolCallID]; ok {