Add new ToolCallPart.id field for OpenAI Responses

pydantic_ai_slim/pydantic_ai/_parts_manager.py

@@ -312,6 +312,7 @@ def handle_tool_call_part(
         tool_name: str,
         args: str | dict[str, Any] | None,
         tool_call_id: str | None = None,
+        id: str | None = None,
     ) -> ModelResponseStreamEvent:
         """Immediately create or fully-overwrite a ToolCallPart with the given information.
 
@@ -323,6 +324,7 @@ def handle_tool_call_part(
             tool_name: The name of the tool being invoked.
             args: The arguments for the tool call, either as a string, a dictionary, or None.
             tool_call_id: An optional string identifier for this tool call.
+            id: An optional identifier for this tool call part.
 
         Returns:
             ModelResponseStreamEvent: A `PartStartEvent` indicating that a new tool call part
@@ -332,6 +334,7 @@ def handle_tool_call_part(
             tool_name=tool_name,
             args=args,
             tool_call_id=tool_call_id or _generate_tool_call_id(),
+            id=id,
         )
         if vendor_part_id is None:
             # vendor_part_id is None, so we unconditionally append a new ToolCallPart to the end of the list

pydantic_ai_slim/pydantic_ai/messages.py

@@ -1052,6 +1052,13 @@ class BaseToolCallPart:
     In case the tool call id is not provided by the model, Pydantic AI will generate a random one.
     """
 
+    _: KW_ONLY
+
+    id: str | None = None
+    """An optional identifier of the tool call part, separate from the tool call ID.
+
+    This is used by some APIs like OpenAI Responses."""
+
     def args_as_dict(self) -> dict[str, Any]:
         """Return the arguments as a Python dictionary.
 

pydantic_ai_slim/pydantic_ai/models/openai.py

@@ -1005,7 +1005,12 @@ def _process_response(  # noqa: C901
                         items.append(TextPart(content.text, id=item.id))
             elif isinstance(item, responses.ResponseFunctionToolCall):
                 items.append(
-                    ToolCallPart(item.name, item.arguments, tool_call_id=_combine_tool_call_ids(item.call_id, item.id))
+                    ToolCallPart(
+                        item.name,
+                        item.arguments,
+                        tool_call_id=item.call_id,
+                        id=item.id,
+                    )
                 )
             elif isinstance(item, responses.ResponseCodeInterpreterToolCall):
                 call_part, return_part, file_parts = _map_code_interpreter_tool_call(item, self.system)
@@ -1361,6 +1366,7 @@ async def _map_messages(  # noqa: C901
                     elif isinstance(item, ToolCallPart):
                         call_id = _guard_tool_call_id(t=item)
                         call_id, id = _split_combined_tool_call_id(call_id)
+                        id = id or item.id
 
                         param = responses.ResponseFunctionToolCallParam(
                             name=item.tool_name,
@@ -1724,7 +1730,8 @@ async def _get_event_iterator(self) -> AsyncIterator[ModelResponseStreamEvent]:
                         vendor_part_id=chunk.item.id,
                         tool_name=chunk.item.name,
                         args=chunk.item.arguments,
-                        tool_call_id=_combine_tool_call_ids(chunk.item.call_id, chunk.item.id),
+                        tool_call_id=chunk.item.call_id,
+                        id=chunk.item.id,
                     )
                 elif isinstance(chunk.item, responses.ResponseReasoningItem):
                     pass
@@ -1963,18 +1970,15 @@ def _map_usage(response: chat.ChatCompletion | ChatCompletionChunk | responses.R
         return u
 
 
-def _combine_tool_call_ids(call_id: str, id: str | None) -> str:
+def _split_combined_tool_call_id(combined_id: str) -> tuple[str, str | None]:
     # When reasoning, the Responses API requires the `ResponseFunctionToolCall` to be returned with both the `call_id` and `id` fields.
-    # Our `ToolCallPart` has only the `call_id` field, so we combine the two fields into a single string.
-    return f'{call_id}|{id}' if id else call_id
+    # Before our `ToolCallPart` gained the `id` field alongside `tool_call_id` field, we combined the two fields into a single string stored on `tool_call_id`.
 
-
-def _split_combined_tool_call_id(combined_id: str) -> tuple[str, str | None]:
     if '|' in combined_id:
         call_id, id = combined_id.split('|', 1)
         return call_id, id
     else:
-        return combined_id, None  # pragma: no cover
+        return combined_id, None
 
 
 def _map_code_interpreter_tool_call(

tests/models/cassettes/test_openai_responses/test_openai_responses_history_with_combined_tool_call_id.yaml

@@ -0,0 +1,148 @@
+interactions:
+- request:
+    headers:
+      accept:
+      - application/json
+      accept-encoding:
+      - gzip, deflate
+      connection:
+      - keep-alive
+      content-length:
+      - '834'
+      content-type:
+      - application/json
+      host:
+      - api.openai.com
+    method: POST
+    parsed_body:
+      include:
+      - reasoning.encrypted_content
+      input:
+      - content: What is the largest city in the user country?
+        role: user
+      - arguments: '{}'
+        call_id: call_ZWkVhdUjupo528U9dqgFeRkH
+        id: fc_68477f0bb8e4819cba6d781e174d77f8001fd29e2d5573f7
+        name: get_user_country
+        type: function_call
+      - call_id: call_ZWkVhdUjupo528U9dqgFeRkH
+        output: Mexico
+        type: function_call_output
+      - content: What is the largest city in the user country?
+        role: user
+      model: gpt-5
+      previous_response_id: null
+      stream: false
+      tool_choice: required
+      tools:
+      - description: The final response which ends this conversation
+        name: final_result
+        parameters:
+          additionalProperties: false
+          properties:
+            city:
+              type: string
+            country:
+              type: string
+          required:
+          - city
+          - country
+          type: object
+        strict: true
+        type: function
+    uri: https://api.openai.com/v1/responses
+  response:
+    headers:
+      alt-svc:
+      - h3=":443"; ma=86400
+      connection:
+      - keep-alive
+      content-length:
+      - '5572'
+      content-type:
+      - application/json
+      openai-organization:
+      - pydantic-28gund
+      openai-processing-ms:
+      - '6305'
+      openai-project:
+      - proj_dKobscVY9YJxeEaDJen54e3d
+      openai-version:
+      - '2020-10-01'
+      strict-transport-security:
+      - max-age=31536000; includeSubDomains; preload
+      transfer-encoding:
+      - chunked
+    parsed_body:
+      background: false
+      billing:
+        payer: developer
+      created_at: 1760355047
+      error: null
+      id: resp_001fd29e2d5573f70068ece2e6dfbc819c96557f0de72802be
+      incomplete_details: null
+      instructions: null
+      max_output_tokens: null
+      max_tool_calls: null
+      metadata: {}
+      model: gpt-5-2025-08-07
+      object: response
+      output:
+      - encrypted_content: gAAAAABo7OLt_-yMcMz15n_JkwU0selGH2vqiwJDNU86YIjY_jQLXid4usIFjjCppiyOnJjtU_C6e7jUIKnfZRBt1DHVFMGpAVvTBZBVdJhXl0ypGjkAj3Wv_3ecAG9oU3DoUMKrbwEMqL0LaSfNSN1qgCTt-RL2sgeEDgFeiOpX40BWgS8tVMfR4_qBxJcp8KeYvw5niPgwcMF3UPIEjHlaVpglJH2SzZtTOdxeFDfYbnvdWTMvwYFIc0jKOREG_-hZE4AznhHdSLV2-I5nGlxuxqaI4GQCk-Fp8Cvcy15_NYYP62ii50VlR6HPp_gQZEetwgC5pThsiuuG7-n1hGOnsj8gZyjSKsMe2KpzlYzhT7ighmArDVEx8Utvp1FXikqGkEzt4RTqqPInp9kuvqQTSyd8JZ6BEetRl1EuZXT7zXrzLwFN7Vm_gqixmf6mLXZUw6vg6LqGkhSh5fo6C7akPTwwJXjVJ37Dzfejo6RiVKOT-_9sdYCHW2kZ9XfQAmRQfB97UpSZ8QrVfaKy_uRIHLexs8QrQvKuw-uHDQBAL3OEmSTzHzCQ-q7b0FHr514Z29l9etavHNVdpeleWGo6VEtLWGQyblIdIBtf946YnQvr6NYIR8uATn9Z91rr8FsFJTpJh_v5iGA2f8rfPRu27nmw-q8XnPVc_FYCZDk08r_YhdEJZn1INBi8wYSWmpib8VxNpkFO7FFRuK-F8rh3MTpYgIOqPQYbf3LCRvKukTwv1b3mjSKVpHQSm_s6s7djdD-rLuc22-3_MLd0ii4_oOT8w51TQIM61LtonGvxUqf4oKHSUFCVnrWWiT-0ttdpwpJ_iB5frnEeY2mWyU1u7sd38BI3dOzoM82IFaIm98g9fa99bmoA7Z7gI60tzyF8YbJmWF-PCwyKHJ7B1MbCBonO36NmeEM-SplrR54fGykxTmwvtbYGhd5f0cdYzD0zulRDj-AhOd96rrUB_fIgoQGTXey8L_w0whcnVTWdG6is-rx8373Sz8ZRoE5RiLWW1mfHzVXxwslphx4BedRVF0tL-1YO7sg5MXhHCf6hpw8dOht-21NMrb1F1DQadFE_fhySFl-TgOD5BlhAuupLMsqcCIa4lcXP_loyA4ERP6WSdz2Bybz7_1eOiflfVodRrNqvr_DnL0NEXD_JkYTeIn84ziarFV7U7ZnkMvRiA_p1fWdbHTsE_8lu1rsf8fcJ1e76_6ycPkOc4TrOZw8gVRb7gIbMMVrv72BT_sFhW7GkXrzCQpQaeybmRw-bjFhkMMjMDYGXkA_H0q2Zfyh3zCOoa40hl2cqRWp7n1XuafmtKG_F8e9hyWox0q7AhZr5HOOaHz8r3O3-dmNl1KP52bqA8S72rLDslAOQlDupmAQgAmkm5ApYeYcEBredN78jHQ1pviUEI2-3qr4ClXZFHPa54AJ_q4HQ-EcKXEcYQglG21mSUy_tFQF-m4X46Qu8yYWcBVW4E0CG3wbvYx0BCdbc5RhIDkJo1elxLK8XS64lpFkCWy62xLVeMuVuCj8q84-Kk7tZ7gtMtLV9PHQCdbl3s2pAzMfuNIBJog6-HPmwha2n9T0Md5qF7OqCtnYWOWUfIMmQVcdW-ECGsQy9uIUmpsOjdtH31hrX3MUEhIOUB5xErLwfp-_s22ciAY_ap3JlYAiTKGlMCxKxTzK7wWEG_nYhDXC1Afj2z-tgvYhtn9MyDf2v0aIpDM9BoTOLEO-ButzylJ06pJlrJhpdvklvwJxUiuhlwy0bHNilb4Zv4QwnUv3DCrIeKe1ne90vEXe6YlDwSMeWJcz1DZIQBvVcNlN8q2y8Rae3lMWzsvD0YXrcXp02ckYoLSOQZgNYviGYLsgRgPGiIkncjSDt7WWV6td3l-zTrP6MT_hKigmg5F5_F6tS1bKb0jlQBZd0NP-_L_TPqMGRjCYG8johd6VyMiagslDjxG39Dh2wyTI19ZW7h_AOuOpnfkt2armqiq6iGfevA3malqkNakb6mFAS04J9O0butWVAw4yiPCEcLuDNAzzi_qrqLee4gkjh0NplvfGCaE6qqYms61GJbJC4wge6vjyTakurbqWEV3YoR3y_dn-0pjQ7TOx9kkruDwg0nZIV5O6yYxaulmbuvo3fs5CZb9ptZPD0MzGZj7CZU2MDCa4a4gr0McOx2MricxSzIu6emuRUzZuC6C1JxPRC00M0TrZNMIe_WVa9fXDLV1ULEAIMwMXzNT9zV6yiYQCwhkp30Wqde3W0LlIRpSbDuJXcvT8OCbXkdPNIScccdT9LvUQQ--hU2P45kisOev3TYn7yv-pdxM3u1KFNwuFxedSArMBPg7GDz1BOxDQRzv0mfwbf_CcoFbuyj7Tf4zWO46HVdHeRNbvIE--bnaSYD-UFaKknp8ZsBQQhBU_2TEca3fKwmg81-g7Vdb28QUZEuPzgE4ekxZejkKpiKqlLC5nJYgvXrqk2H35D51mYdzPs0ST05Mc41x9MFm_YOLxSFyA0yGAKVINmD5wT6kvRflPkgoksd2ryIvo4KMw3oZQKodv5By0mSJ8iX2vhTGylxiM8wj-ICyNuOsaRFrcMSpX7tZbXcDyysApdmx217BSADoQiNZBLngF7ptxc2QGyo3CwuDjaljwmSgL9KeGthd1RJFd826M287IPpCjLM4WRquCL_E0pQryNqOMn-ZEOCAlBjE37290EhkjKbhiGBEnHUvSbhoH4nL47AmunP_Q5aqh5173VfyoyaybuS3fXjQ5WO0kyFjMdD-a7C6PVdwToCTP-TljoF2YnQKCiqUGs9gNHS9mYhQSXzY4uuGlTHLfKB4JKS5_MQHvwI9zCbTvVG854fPuo_2mzSh-y8TSzBWPokhYWI_q095Sh6tOqDIJNMGyjI2GDFRSyKpKhIFCLyU2JEo9B6l91jPlir0XI8ZOQfBd9J0I4JIqnyoj40_1bF1zUDGc014bdGfxazxwlGph_ysKAP39wV7X9DBFS3ZmeSIn-r3s-sci0HmwnJUb2r03m40rFuNTV1cJMAFP7ZY7PQQQ0TtlO_al0uedaOWylLauap_eoRqc6xGJ2rSz1e7cOevksUlAqzK5xknYKHlsW970xuDGHKOZnKPg8O9nb2PKrcjwEQF5RFPc3l8TtOUXPhhvTERZFGoEuGuSuSp1cJhzba06yPnL-wE3CstYUm3jvkaUme6kKqM4tWBCQDg-_2PYf24xXYlmkIklylskqId826Y3pVVUd7e0vQO0POPeVYU1qwtTp7Ln-MhYEWexxptdNkVQ-kWx63w6HXF6_kefSxaf0UcvL8tOV73u7w_udle9MC_TXgwJZpoW2tSi5HETjQ_i28FAP2iJmclWOm3gP08cMiXvgpTpjzh6meBdvKepnifl_ivPzRnyjz3mYCZH-UJ4LmOHIonv-8arnckhCwHoFIpaIX7eSZyY0JcbBETKImtUwrlTSlbD8l02KDtqw2FJURtEWI5dC1sTS8c2HcyjXyQDA9A25a0M1yIgZyaadODGQ1zoa9xXB
+        id: rs_001fd29e2d5573f70068ece2e816fc819c82755f049c987ea4
+        summary: []
+        type: reasoning
+      - arguments: '{"city":"Mexico City","country":"Mexico"}'
+        call_id: call_LIXPi261Xx3dGYzlDsOoyHGk
+        id: fc_001fd29e2d5573f70068ece2ecc140819c97ca83bd4647a717
+        name: final_result
+        status: completed
+        type: function_call
+      parallel_tool_calls: true
+      previous_response_id: null
+      prompt_cache_key: null
+      reasoning:
+        effort: medium
+        summary: null
+      safety_identifier: null
+      service_tier: default
+      status: completed
+      store: true
+      temperature: 1.0
+      text:
+        format:
+          type: text
+        verbosity: medium
+      tool_choice: required
+      tools:
+      - description: The final response which ends this conversation
+        name: final_result
+        parameters:
+          additionalProperties: false
+          properties:
+            city:
+              type: string
+            country:
+              type: string
+          required:
+          - city
+          - country
+          type: object
+        strict: true
+        type: function
+      top_logprobs: 0
+      top_p: 1.0
+      truncation: disabled
+      usage:
+        input_tokens: 103
+        input_tokens_details:
+          cached_tokens: 0
+        output_tokens: 409
+        output_tokens_details:
+          reasoning_tokens: 384
+        total_tokens: 512
+      user: null
+    status:
+      code: 200
+      message: OK
+version: 1