diff --git a/src/exo/master/adapters/chat_completions.py b/src/exo/master/adapters/chat_completions.py
index 3e013079..efc89a56 100644
--- a/src/exo/master/adapters/chat_completions.py
+++ b/src/exo/master/adapters/chat_completions.py
@@ -3,7 +3,6 @@
 import time
 from collections.abc import AsyncGenerator
 from typing import Any
-from uuid import uuid4
 
 from exo.shared.types.api import (
     ChatCompletionChoice,
@@ -141,7 +140,7 @@ async def generate_chat_stream(
         if isinstance(chunk, ToolCallChunk):
             tool_call_deltas = [
                 ToolCall(
-                    id=str(uuid4()),
+                    id=tool.id,
                     index=i,
                     function=tool,
                 )
@@ -207,7 +206,7 @@ async def collect_chat_response(
         if isinstance(chunk, ToolCallChunk):
             tool_calls.extend(
                 ToolCall(
-                    id=str(uuid4()),
+                    id=tool.id,
                     index=i,
                     function=tool,
                 )
diff --git a/src/exo/master/adapters/claude.py b/src/exo/master/adapters/claude.py
index 6c17b49c..2d7da6b1 100644
--- a/src/exo/master/adapters/claude.py
+++ b/src/exo/master/adapters/claude.py
@@ -3,7 +3,6 @@
 import json
 from collections.abc import AsyncGenerator
 from typing import Any
-from uuid import uuid4
 
 from exo.shared.types.api import FinishReason
 from exo.shared.types.chunks import ErrorChunk, TokenChunk, ToolCallChunk
@@ -179,7 +178,7 @@ async def collect_claude_response(
             for tool in chunk.tool_calls:
                 tool_use_blocks.append(
                     ClaudeToolUseBlock(
-                        id=f"toolu_{uuid4().hex[:24]}",
+                        id=f"toolu_{tool.id}",
                         name=tool.name,
                         input=json.loads(tool.arguments),  # pyright: ignore[reportAny]
                     )
@@ -264,7 +263,7 @@ async def generate_claude_stream(
 
             # Emit tool_use content blocks
             for tool in chunk.tool_calls:
-                tool_id = f"toolu_{uuid4().hex[:24]}"
+                tool_id = f"toolu_{tool.id}"
                 tool_input_json = tool.arguments
 
                 # content_block_start for tool_use
diff --git a/src/exo/master/adapters/responses.py b/src/exo/master/adapters/responses.py
index c2a416ac..a101d573 100644
--- a/src/exo/master/adapters/responses.py
+++ b/src/exo/master/adapters/responses.py
@@ -3,7 +3,6 @@
 from collections.abc import AsyncGenerator
 from itertools import count
 from typing import Any
-from uuid import uuid4
 
 from exo.shared.types.chunks import ErrorChunk, TokenChunk, ToolCallChunk
 from exo.shared.types.common import CommandId
@@ -140,8 +139,8 @@ async def collect_responses_response(
             for tool in chunk.tool_calls:
                 function_call_items.append(
                     ResponseFunctionCallItem(
-                        id=f"fc_{uuid4().hex[:24]}",
-                        call_id=f"call_{uuid4().hex[:24]}",
+                        id=f"fc_{tool.id}",
+                        call_id=f"call_{tool.id}",
                         name=tool.name,
                         arguments=tool.arguments,
                     )
@@ -246,8 +245,8 @@ async def generate_responses_stream(
         if isinstance(chunk, ToolCallChunk):
             last_stats = chunk.stats or last_stats
             for tool in chunk.tool_calls:
-                fc_id = f"fc_{uuid4().hex[:24]}"
-                call_id = f"call_{uuid4().hex[:24]}"
+                fc_id = f"fc_{tool.id}"
+                call_id = f"call_{tool.id}"
 
                 # response.output_item.added for function_call
                 fc_item = ResponseFunctionCallItem(
diff --git a/src/exo/shared/types/api.py b/src/exo/shared/types/api.py
index 97d7041d..da519a12 100644
--- a/src/exo/shared/types/api.py
+++ b/src/exo/shared/types/api.py
@@ -1,6 +1,7 @@
 import time
 from collections.abc import Generator
 from typing import Annotated, Any, Literal
+from uuid import uuid4
 
 from pydantic import BaseModel, Field, field_validator
 from pydantic_core import PydanticUseDefault
@@ -60,6 +61,7 @@ class ChatCompletionMessageText(BaseModel):
 
 
 class ToolCallItem(BaseModel):
+    id: str = Field(default_factory=lambda: str(uuid4()))
     name: str
     arguments: str
 
diff --git a/src/exo/worker/engines/mlx/generator/generate.py b/src/exo/worker/engines/mlx/generator/generate.py
index 5af73e42..fa618d9c 100644
--- a/src/exo/worker/engines/mlx/generator/generate.py
+++ b/src/exo/worker/engines/mlx/generator/generate.py
@@ -298,6 +298,9 @@ def mlx_generate(
     )
     max_stop_len = max((len(s) for s in stop_sequences), default=0)
 
+    mx_barrier(group)
+    logger.info("Ready to prefill")
+
     # Prefill cache with all tokens except the last one
     prefill_tps, prefill_tokens, ssm_snapshots_list = prefill(
         model,
diff --git a/src/exo/worker/runner/runner.py b/src/exo/worker/runner/runner.py
index e522f6c2..2764f024 100644
--- a/src/exo/worker/runner/runner.py
+++ b/src/exo/worker/runner/runner.py
@@ -810,8 +810,9 @@ def patch_kimi_tokenizer(tokenizer: TokenizerWrapper):
 
     # kimi has a fixed function naming scheme, with a json formatted arg
     #   functions.multiply:0 <|tool_call_argument_begin|> {"a": 2, "b": 3}
+    #   Also needs to handle tools like call_0<|tool_call_argument_begin|>{"filePath": "..."}
     _func_name_regex = re.compile(
-        r"^\s*(.+):\d+\s*<\|tool_call_argument_begin\|>", re.DOTALL
+        r"^\s*(.+)[:](\d+)\s*<\|tool_call_argument_begin\|>", re.DOTALL
     )
     _func_arg_regex = re.compile(r"<\|tool_call_argument_begin\|>\s*(.*)\s*", re.DOTALL)
 
@@ -835,9 +836,10 @@ def patch_kimi_tokenizer(tokenizer: TokenizerWrapper):
         func_name_match = _func_name_regex.search(text)
         if func_name_match is None:
             raise ValueError(f"Could not parse function name from tool call: {text!r}")
-        func_name = func_name_match.group(1)
+        original_func_name = func_name_match.group(1)
+        tool_id = func_name_match.group(2)
         # strip off the `functions.` prefix, if it exists.
-        func_name = func_name[func_name.find(".") + 1 :]
+        func_name = original_func_name[original_func_name.find(".") + 1 :]
 
         func_args_match = _func_arg_regex.search(text)
         if func_args_match is None:
@@ -846,7 +848,11 @@ def patch_kimi_tokenizer(tokenizer: TokenizerWrapper):
         # the args should be valid json - no need to check against our tools to deserialize
         arg_dct = _deserialize(func_args)  # pyright: ignore[reportAny]
 
-        return dict(name=func_name, arguments=arg_dct)  # pyright: ignore[reportAny]
+        return dict(
+            id=f"{original_func_name}:{tool_id}",
+            name=func_name,
+            arguments=arg_dct,  # pyright: ignore[reportAny]
+        )
 
     tokenizer._tool_call_start = tool_call_start
     tokenizer._tool_call_end = tool_call_end
@@ -929,7 +935,13 @@ def _validate_single_tool(obj: dict[str, Any]) -> ToolCallItem:
         and ((args := obj.get("arguments")) is not None)
         and isinstance(name, str)
     ):
-        return ToolCallItem(name=name, arguments=json.dumps(args))
+        raw_id: object = obj.get("id")
+        extra = {"id": str(raw_id)} if raw_id is not None else {}
+        return ToolCallItem(
+            **extra,
+            name=name,
+            arguments=json.dumps(args),
+        )
     else:
         raise ValidationError