fix(core): keep patch description unchanged

packages/ai/src/protocols/open-responses.ts

@@ -176,14 +176,14 @@ export const InputItem = Schema.Union([
   HostedToolItem,
 ])
 type OpenResponsesInputItem = Schema.Schema.Type<typeof InputItem>
-export type ExtendedHostedToolItem = {
+export type HostedToolReplayItem = {
   readonly type: string
   readonly id: string
   readonly [key: string]: unknown
 }
 type LoweredInputItem =
   | OpenResponsesInputItem
-  | ExtendedHostedToolItem
+  | HostedToolReplayItem
   | {
       readonly type: "message"
       readonly id?: string
@@ -373,7 +373,7 @@ export const Event = Schema.StructWithRest(
 )
 export type Event = Schema.Schema.Type<typeof Event>
 
-export interface Extension {
+export interface ProviderAdapter {
   readonly id: string
   readonly name: string
   readonly lowerMedia?: (input: {
@@ -381,10 +381,10 @@ export interface Extension {
     readonly media: ProviderShared.NormalizedMedia
     readonly request: LLMRequest
   }) => MediaInput | undefined
-  readonly lowerHostedToolItem?: (item: unknown) => ExtendedHostedToolItem | undefined
+  readonly restoreHostedToolItem?: (item: unknown) => HostedToolReplayItem | undefined
 }
 
-const BASE: Extension = { id: ADAPTER, name: NAME }
+const BASE_ADAPTER: ProviderAdapter = { id: ADAPTER, name: NAME }
 
 export interface ParserState {
   readonly id: string
@@ -482,12 +482,12 @@ const lowerReasoning = (part: ReasoningPart, providerMetadataKey: string): OpenR
 const lowerMedia = Effect.fn("OpenResponses.lowerMedia")(function* (
   part: MediaPart,
   request: LLMRequest,
-  extension: Extension,
+  adapter: ProviderAdapter,
   target: "message" | "tool-result",
 ) {
   const media = ProviderShared.normalizeMedia(part)
-  const extended = extension.lowerMedia?.({ part, media, request })
-  if (extended) return extended
+  const providerMedia = adapter.lowerMedia?.({ part, media, request })
+  if (providerMedia) return providerMedia
   const url =
     typeof part.data === "string" && (part.data.startsWith("https://") || part.data.startsWith("http://"))
       ? part.data
@@ -507,17 +507,17 @@ const lowerMedia = Effect.fn("OpenResponses.lowerMedia")(function* (
 const lowerUserContent = Effect.fnUntraced(function* (
   part: LLMRequest["messages"][number]["content"][number],
   request: LLMRequest,
-  extension: Extension,
+  adapter: ProviderAdapter,
 ) {
   if (part.type === "text") return { type: "input_text" as const, text: part.text }
-  if (part.type === "media") return yield* lowerMessageMedia(part, request, extension)
-  return yield* ProviderShared.unsupportedContent(extension.name, "user", ["text", "media"])
+  if (part.type === "media") return yield* lowerMessageMedia(part, request, adapter)
+  return yield* ProviderShared.unsupportedContent(adapter.name, "user", ["text", "media"])
 })
 
-const lowerMessageMedia = Effect.fnUntraced(function* (part: MediaPart, request: LLMRequest, extension: Extension) {
-  const lowered = yield* lowerMedia(part, request, extension, "message")
+const lowerMessageMedia = Effect.fnUntraced(function* (part: MediaPart, request: LLMRequest, adapter: ProviderAdapter) {
+  const lowered = yield* lowerMedia(part, request, adapter, "message")
   if (lowered.type === "input_video")
-    return yield* ProviderShared.invalidRequest(`${extension.name} user messages do not support input_video`)
+    return yield* ProviderShared.invalidRequest(`${adapter.name} user messages do not support input_video`)
   return lowered
 })
 
@@ -526,13 +526,13 @@ const lowerMessageMedia = Effect.fnUntraced(function* (part: MediaPart, request:
 const lowerToolResultContentItem = Effect.fnUntraced(function* (
   item: Content,
   request: LLMRequest,
-  extension: Extension,
+  adapter: ProviderAdapter,
 ) {
   if (item.type === "text") return { type: "input_text" as const, text: item.text }
   return yield* lowerMedia(
     { type: "media", mediaType: item.mime, data: item.uri, filename: item.name },
     request,
-    extension,
+    adapter,
     "tool-result",
   )
 })
@@ -540,30 +540,33 @@ const lowerToolResultContentItem = Effect.fnUntraced(function* (
 const lowerHostedToolResultContentItem = Effect.fnUntraced(function* (
   item: Content,
   request: LLMRequest,
-  extension: Extension,
+  adapter: ProviderAdapter,
 ) {
   if (item.type === "text") return { type: "input_text" as const, text: item.text }
   return yield* lowerMessageMedia(
     { type: "media", mediaType: item.mime, data: item.uri, filename: item.name },
     request,
-    extension,
+    adapter,
   )
 })
 
 const lowerToolResultOutput = Effect.fnUntraced(function* (
   part: ToolResultPart,
   request: LLMRequest,
-  extension: Extension,
+  adapter: ProviderAdapter,
 ) {
   // Text/json/error results are encoded as a plain string for backward
   // compatibility with existing cassettes and provider expectations.
   if (part.result.type !== "content") return ProviderShared.toolResultText(part)
   // Preserve the narrowed array element type when compiled through a consumer package.
   const content: ReadonlyArray<Content> = part.result.value
-  return yield* Effect.forEach(content, (item) => lowerToolResultContentItem(item, request, extension))
+  return yield* Effect.forEach(content, (item) => lowerToolResultContentItem(item, request, adapter))
 })
 
-const lowerMessages = Effect.fn("OpenResponses.lowerMessages")(function* (request: LLMRequest, extension: Extension) {
+const lowerMessages = Effect.fn("OpenResponses.lowerMessages")(function* (
+  request: LLMRequest,
+  adapter: ProviderAdapter,
+) {
   const input: LoweredInputItem[] = []
   const providerMetadataKey = request.model.route.providerMetadataKey ?? "openresponses"
 
@@ -571,13 +574,13 @@ const lowerMessages = Effect.fn("OpenResponses.lowerMessages")(function* (reques
     if (message.role === "system") {
       input.push({
         role: "developer",
-        content: ProviderShared.joinText(yield* ProviderShared.systemUpdateText(extension.name, message)),
+        content: ProviderShared.joinText(yield* ProviderShared.systemUpdateText(adapter.name, message)),
       })
       continue
     }
 
     if (message.role === "user") {
-      const content = yield* Effect.forEach(message.content, (part) => lowerUserContent(part, request, extension))
+      const content = yield* Effect.forEach(message.content, (part) => lowerUserContent(part, request, adapter))
       if (content.length > 0) input.push({ role: "user", content })
       continue
     }
@@ -644,7 +647,7 @@ const lowerMessages = Effect.fn("OpenResponses.lowerMessages")(function* (reques
               ? undefined
               : Schema.is(HostedToolItem)(part.result.value)
                 ? part.result.value
-                : extension.lowerHostedToolItem?.(part.result.value)
+                : adapter.restoreHostedToolItem?.(part.result.value)
           if (id !== undefined && hosted?.id === id) {
             if (!hostedToolItems.has(id)) {
               input.push(hosted)
@@ -658,13 +661,11 @@ const lowerMessages = Effect.fn("OpenResponses.lowerMessages")(function* (reques
               : [{ type: "text", text: ProviderShared.toolResultText(part) }]
           input.push({
             role: "user",
-            content: yield* Effect.forEach(content, (item) =>
-              lowerHostedToolResultContentItem(item, request, extension),
-            ),
+            content: yield* Effect.forEach(content, (item) => lowerHostedToolResultContentItem(item, request, adapter)),
           })
           continue
         }
-        return yield* ProviderShared.unsupportedContent(extension.name, "assistant", [
+        return yield* ProviderShared.unsupportedContent(adapter.name, "assistant", [
           "text",
           "reasoning",
           "tool-call",
@@ -677,11 +678,11 @@ const lowerMessages = Effect.fn("OpenResponses.lowerMessages")(function* (reques
 
     for (const part of message.content) {
       if (!ProviderShared.supportsContent(part, ["tool-result"]))
-        return yield* ProviderShared.unsupportedContent(extension.name, "tool", ["tool-result"])
+        return yield* ProviderShared.unsupportedContent(adapter.name, "tool", ["tool-result"])
       input.push({
         type: "function_call_output",
         call_id: part.id,
-        output: yield* lowerToolResultOutput(part, request, extension),
+        output: yield* lowerToolResultOutput(part, request, adapter),
       })
     }
   }
@@ -733,28 +734,28 @@ const allowedToolChoice = (request: LLMRequest) => {
   }
 }
 
-export const fromRequestWithExtension = Effect.fn("OpenResponses.fromRequestWithExtension")(function* (
+export const fromRequestWithAdapter = Effect.fn("OpenResponses.fromRequestWithAdapter")(function* (
   request: LLMRequest,
-  extension: Extension,
+  adapter: ProviderAdapter,
 ) {
   const generation = request.generation
   const toolSchemaCompatibility = request.model.compatibility?.toolSchema
   return {
     model: request.model.id,
-    input: yield* lowerMessages(request, extension),
+    input: yield* lowerMessages(request, adapter),
     tools:
       request.tools.length === 0
         ? undefined
         : yield* Effect.forEach(request.tools, (tool) =>
             lowerTool(
-              extension.name,
+              adapter.name,
               tool,
               ToolSchemaProjection.modelCompatibility(tool.inputSchema, toolSchemaCompatibility),
             ),
           ),
     tool_choice:
       allowedToolChoice(request) ??
-      (request.toolChoice ? yield* lowerToolChoice(extension.name, request.toolChoice) : undefined),
+      (request.toolChoice ? yield* lowerToolChoice(adapter.name, request.toolChoice) : undefined),
     stream: true as const,
     max_output_tokens: generation?.maxTokens,
     temperature: generation?.temperature,
@@ -768,7 +769,7 @@ export const fromRequestWithExtension = Effect.fn("OpenResponses.fromRequestWith
 const decodeBody = ProviderShared.validateWith(Schema.decodeUnknownEffect(OpenResponsesBody))
 
 export const fromRequest = Effect.fn("OpenResponses.fromRequest")(function* (request: LLMRequest) {
-  return yield* decodeBody(yield* fromRequestWithExtension(request, BASE))
+  return yield* decodeBody(yield* fromRequestWithAdapter(request, BASE_ADAPTER))
 })
 
 // =============================================================================
@@ -1408,9 +1409,9 @@ export const step = (state: ParserState, input: Event) => {
  * The provider-neutral Open Responses protocol. Provider-specific Responses
  * implementations compose this baseline with their own tools and event variants.
  */
-export const initial = (request: LLMRequest, extension: Extension = BASE): ParserState => ({
-  id: extension.id,
-  name: extension.name,
+export const initial = (request: LLMRequest, adapter: ProviderAdapter = BASE_ADAPTER): ParserState => ({
+  id: adapter.id,
+  name: adapter.name,
   providerMetadataKey: request.model.route.providerMetadataKey ?? "openresponses",
   hasFunctionCall: false,
   tools: ToolStream.empty<string>(),

packages/ai/src/protocols/openai-responses.ts

@@ -86,11 +86,11 @@ const OpenAIResponsesBody = Schema.Struct({
 })
 export type OpenAIResponsesBody = Schema.Schema.Type<typeof OpenAIResponsesBody>
 
-const extension = {
+const adapter = {
   id: ADAPTER,
   name: NAME,
-  lowerHostedToolItem: (item: unknown) => (Schema.is(OpenAIResponsesHostedToolItem)(item) ? item : undefined),
-} satisfies OpenResponses.Extension
+  restoreHostedToolItem: (item: unknown) => (Schema.is(OpenAIResponsesHostedToolItem)(item) ? item : undefined),
+} satisfies OpenResponses.ProviderAdapter
 
 const nativeImageToolInput = (tool: ToolDefinition) => {
   const native = tool.native?.openai
@@ -125,9 +125,9 @@ const lowerToolChoice = (toolChoice: NonNullable<LLMRequest["toolChoice"]>, tool
 const decodeBody = ProviderShared.validateWith(Schema.decodeUnknownEffect(OpenAIResponsesBody))
 
 const fromRequest = Effect.fn("OpenAIResponses.fromRequest")(function* (request: LLMRequest) {
-  const body = yield* OpenResponses.fromRequestWithExtension(
+  const body = yield* OpenResponses.fromRequestWithAdapter(
     LLMRequest.update(request, { tools: [], toolChoice: undefined }),
-    extension,
+    adapter,
   )
   const toolSchemaCompatibility = request.model.compatibility?.toolSchema
   const parallelToolCalls = OpenResponses.resolveParallelToolCalls(request)
@@ -204,7 +204,7 @@ export const protocol = Protocol.make({
   },
   stream: {
     event: OpenResponses.protocol.stream.event,
-    initial: (request) => OpenResponses.initial(request, extension),
+    initial: (request) => OpenResponses.initial(request, adapter),
     step,
     terminal: OpenResponses.terminal,
   },

packages/ai/src/protocols/xai-responses.ts

@@ -36,15 +36,15 @@ const XAIResponsesBody = Schema.Struct({
   stream: Schema.Literal(true),
 })
 
-const extension = {
+const adapter = {
   id: ADAPTER,
   name: NAME,
-  lowerHostedToolItem: (item: unknown) => (Schema.is(XAIResponsesHostedToolItem)(item) ? item : undefined),
-} satisfies OpenResponses.Extension
+  restoreHostedToolItem: (item: unknown) => (Schema.is(XAIResponsesHostedToolItem)(item) ? item : undefined),
+} satisfies OpenResponses.ProviderAdapter
 
 const decodeBody = ProviderShared.validateWith(Schema.decodeUnknownEffect(XAIResponsesBody))
 const fromRequest = Effect.fn("XAIResponses.fromRequest")(function* (request: LLMRequest) {
-  return yield* decodeBody(yield* OpenResponses.fromRequestWithExtension(request, extension))
+  return yield* decodeBody(yield* OpenResponses.fromRequestWithAdapter(request, adapter))
 })
 
 const HOSTED_TOOLS = {
@@ -78,7 +78,7 @@ export const protocol = Protocol.make({
   },
   stream: {
     event: OpenResponses.protocol.stream.event,
-    initial: (request) => OpenResponses.initial(request, extension),
+    initial: (request) => OpenResponses.initial(request, adapter),
     step,
     terminal: OpenResponses.terminal,
   },

packages/core/src/tool/plugin/patch.ts

@@ -112,7 +112,6 @@ export const Plugin = {
                 return yield* new ToolFailure({ message: "patch rejected: empty patch" })
               }
               const prepared: Prepared[] = []
-              const updates = new Map<string, string>()
               const resolveTarget = Effect.fnUntraced(function* (value: string) {
                 const target = yield* mutation.resolve({ path: value, kind: "file" })
                 if (!target.externalDirectory) return target
@@ -131,6 +130,11 @@ export const Plugin = {
               for (const hunk of hunks) {
                 yield* Effect.gen(function* () {
                   const target = yield* resolveTarget(hunk.path)
+                  if (prepared.some((change) => change.target.absolute === target.absolute)) {
+                    return yield* new ToolFailure({
+                      message: `patch verification failed: invalid patch: multiple operations target ${target.absolute}`,
+                    })
+                  }
                   if (hunk.type === "add") {
                     const content =
                       hunk.contents.endsWith("\n") || hunk.contents === "" ? hunk.contents : `${hunk.contents}\n`
@@ -155,20 +159,15 @@ export const Plugin = {
                     prepared.push({ ...hunk, target, before: content.text, after: "" })
                     return
                   }
-                  const previous = updates.get(target.absolute)
-                  const original =
-                    previous ??
-                    (yield* Effect.gen(function* () {
-                      const content = yield* FileMutation.readText(environment.files, target.absolute).pipe(
-                        Effect.mapError(
-                          (error) =>
-                            new ToolFailure({
-                              message: `patch verification failed: Failed to read file to update ${target.absolute}: ${errorMessage(error)}`,
-                            }),
-                        ),
-                      )
-                      return Bom.join(content.text, content.bom)
-                    }))
+                  const content = yield* FileMutation.readText(environment.files, target.absolute).pipe(
+                    Effect.mapError(
+                      (error) =>
+                        new ToolFailure({
+                          message: `patch verification failed: Failed to read file to update ${target.absolute}: ${errorMessage(error)}`,
+                        }),
+                    ),
+                  )
+                  const original = Bom.join(content.text, content.bom)
                   const before = Bom.split(original).text
                   const update = yield* Effect.try({
                     try: () => Patch.derive(hunk.path, hunk.chunks, original),
@@ -183,7 +182,6 @@ export const Plugin = {
                     after: update.content,
                     moveTarget,
                   })
-                  if (!moveTarget) updates.set(target.absolute, Patch.joinBom(update.content, update.bom))
                 }).pipe(
                   Effect.mapError((error) =>
                     error instanceof ToolFailure

packages/core/test/tool-patch.test.ts

@@ -323,6 +323,43 @@ describe("PatchTool", () => {
     }),
   )
 
+  it.live("rejects multiple operations on the same resolved path before writing any files", () =>
+    withTempTool((directory, registry) =>
+      Effect.gen(function* () {
+        const target = path.join(directory, "duplicate.txt")
+        yield* Effect.promise(() => fs.writeFile(target, "before\n"))
+        const operations = [
+          "*** Add File: duplicate.txt\n+after",
+          "*** Update File: duplicate.txt\n@@\n-before\n+after",
+          "*** Delete File: duplicate.txt",
+        ]
+        for (const first of operations) {
+          for (const second of operations) {
+            for (const alias of ["duplicate.txt", "./duplicate.txt", target]) {
+              expect(
+                yield* executeTool(
+                  registry,
+                  call(
+                    `*** Begin Patch\n*** Add File: earlier.txt\n+earlier\n${first}\n${second.replace("duplicate.txt", alias)}\n*** End Patch`,
+                  ),
+                ),
+              ).toEqual({
+                status: "error",
+                error: {
+                  type: "tool.execution",
+                  message: `patch verification failed: invalid patch: multiple operations target ${target}`,
+                },
+              })
+              expect(yield* Effect.promise(() => fs.readFile(target, "utf8"))).toBe("before\n")
+              expect(yield* exists(path.join(directory, "earlier.txt"))).toBe(false)
+            }
+          }
+        }
+        expect(assertions).toEqual([])
+      }),
+    ),
+  )
+
   it.live("moves and updates a file", () =>
     Effect.acquireUseRelease(
       Effect.promise(() => tmpdir()),
@@ -635,17 +672,17 @@ describe("PatchTool", () => {
     ),
   )
 
-  it.live("applies successive update operations to one file", () =>
+  it.live("applies multiple chunks within one update operation", () =>
     withTempTool((directory, registry) =>
       Effect.gen(function* () {
         const target = path.join(directory, "successive.txt")
         yield* Effect.promise(() => fs.writeFile(target, "a\nb\n"))
-        yield* executeTool(
-          registry,
-          call(
-            "*** Begin Patch\n*** Update File: successive.txt\n@@\n-a\n+A\n*** Update File: successive.txt\n@@\n-b\n+B\n*** End Patch",
+        expect(
+          yield* executeTool(
+            registry,
+            call("*** Begin Patch\n*** Update File: successive.txt\n@@\n-a\n+A\n@@\n-b\n+B\n*** End Patch"),
           ),
-        )
+        ).toMatchObject({ status: "completed" })
         expect(yield* Effect.promise(() => fs.readFile(target, "utf8"))).toBe("A\nB\n")
       }),
     ),