Use LLM APIs responses in token counting

openhands/core/message_utils.py

@@ -29,6 +29,7 @@
 from openhands.events.observation.error import ErrorObservation
 from openhands.events.observation.observation import Observation
 from openhands.events.serialization.event import truncate_content
+from openhands.llm.metrics import Metrics, TokenUsage
 
 
 def events_to_messages(
@@ -362,3 +363,47 @@ def apply_prompt_caching(messages: list[Message]) -> None:
                 -1
             ].cache_prompt = True  # Last item inside the message content
             break
+
+
+def get_token_usage_for_event(event: Event, metrics: Metrics) -> TokenUsage | None:
+    """
+    Returns at most one token usage record for the `model_response.id` in this event's
+    `tool_call_metadata`.
+
+    If no response_id is found, or none match in metrics.token_usages, returns None.
+    """
+    if event.tool_call_metadata and event.tool_call_metadata.model_response:
+        response_id = event.tool_call_metadata.model_response.get('id')
+        if response_id:
+            return next(
+                (
+                    usage
+                    for usage in metrics.token_usages
+                    if usage.response_id == response_id
+                ),
+                None,
+            )
+    return None
+
+
+def get_token_usage_for_event_id(
+    events: list[Event], event_id: int, metrics: Metrics
+) -> TokenUsage | None:
+    """
+    Starting from the event with .id == event_id and moving backwards in `events`,
+    find the first TokenUsage record (if any) associated with a response_id from
+    tool_call_metadata.model_response.id.
+
+    Returns the first match found, or None if none is found.
+    """
+    # find the index of the event with the given id
+    idx = next((i for i, e in enumerate(events) if e.id == event_id), None)
+    if idx is None:
+        return None
+
+    # search backward from idx down to 0
+    for i in range(idx, -1, -1):
+        usage = get_token_usage_for_event(events[i], metrics)
+        if usage is not None:
+            return usage
+    return None

openhands/llm/llm.py

@@ -497,20 +497,21 @@ def _post_completion(self, response: ModelResponse) -> float:
             stats += 'Response Latency: %.3f seconds\n' % latest_latency.latency
 
         usage: Usage | None = response.get('usage')
+        response_id = response.get('id', 'unknown')
 
         if usage:
             # keep track of the input and output tokens
-            input_tokens = usage.get('prompt_tokens')
-            output_tokens = usage.get('completion_tokens')
+            prompt_tokens = usage.get('prompt_tokens', 0)
+            completion_tokens = usage.get('completion_tokens', 0)
 
-            if input_tokens:
-                stats += 'Input tokens: ' + str(input_tokens)
+            if prompt_tokens:
+                stats += 'Input tokens: ' + str(prompt_tokens)
 
-            if output_tokens:
+            if completion_tokens:
                 stats += (
-                    (' | ' if input_tokens else '')
+                    (' | ' if prompt_tokens else '')
                     + 'Output tokens: '
-                    + str(output_tokens)
+                    + str(completion_tokens)
                     + '\n'
                 )
 
@@ -519,7 +520,7 @@ def _post_completion(self, response: ModelResponse) -> float:
                 'prompt_tokens_details'
             )
             cache_hit_tokens = (
-                prompt_tokens_details.cached_tokens if prompt_tokens_details else None
+                prompt_tokens_details.cached_tokens if prompt_tokens_details else 0
             )
             if cache_hit_tokens:
                 stats += 'Input tokens (cache hit): ' + str(cache_hit_tokens) + '\n'
@@ -528,10 +529,20 @@ def _post_completion(self, response: ModelResponse) -> float:
             # but litellm doesn't separate them in the usage stats
             # so we can read it from the provider-specific extra field
             model_extra = usage.get('model_extra', {})
-            cache_write_tokens = model_extra.get('cache_creation_input_tokens')
+            cache_write_tokens = model_extra.get('cache_creation_input_tokens', 0)
             if cache_write_tokens:
                 stats += 'Input tokens (cache write): ' + str(cache_write_tokens) + '\n'
 
+            # Record in metrics
+            # We'll treat cache_hit_tokens as "cache read" and cache_write_tokens as "cache write"
+            self.metrics.add_token_usage(
+                prompt_tokens=prompt_tokens,
+                completion_tokens=completion_tokens,
+                cache_read_tokens=cache_hit_tokens,
+                cache_write_tokens=cache_write_tokens,
+                response_id=response_id,
+            )
+
         # log the stats
         if stats:
             logger.debug(stats)

openhands/llm/metrics.py

@@ -17,18 +17,31 @@ class ResponseLatency(BaseModel):
     response_id: str
 
 
+class TokenUsage(BaseModel):
+    """Metric tracking detailed token usage per completion call."""
+
+    model: str
+    prompt_tokens: int
+    completion_tokens: int
+    cache_read_tokens: int
+    cache_write_tokens: int
+    response_id: str
+
+
 class Metrics:
     """Metrics class can record various metrics during running and evaluation.
-    Currently, we define the following metrics:
-        accumulated_cost: the total cost (USD $) of the current LLM.
-        response_latency: the time taken for each LLM completion call.
+    We track:
+      - accumulated_cost and costs
+      - A list of ResponseLatency
+      - A list of TokenUsage (one per call).
     """
 
     def __init__(self, model_name: str = 'default') -> None:
         self._accumulated_cost: float = 0.0
         self._costs: list[Cost] = []
         self._response_latencies: list[ResponseLatency] = []
         self.model_name = model_name
+        self._token_usages: list[TokenUsage] = []
 
     @property
     def accumulated_cost(self) -> float:
@@ -54,6 +67,16 @@ def response_latencies(self) -> list[ResponseLatency]:
     def response_latencies(self, value: list[ResponseLatency]) -> None:
         self._response_latencies = value
 
+    @property
+    def token_usages(self) -> list[TokenUsage]:
+        if not hasattr(self, '_token_usages'):
+            self._token_usages = []
+        return self._token_usages
+
+    @token_usages.setter
+    def token_usages(self, value: list[TokenUsage]) -> None:
+        self._token_usages = value
+
     def add_cost(self, value: float) -> None:
         if value < 0:
             raise ValueError('Added cost cannot be negative.')
@@ -67,10 +90,33 @@ def add_response_latency(self, value: float, response_id: str) -> None:
             )
         )
 
+    def add_token_usage(
+        self,
+        prompt_tokens: int,
+        completion_tokens: int,
+        cache_read_tokens: int,
+        cache_write_tokens: int,
+        response_id: str,
+    ) -> None:
+        """Add a single usage record."""
+        self._token_usages.append(
+            TokenUsage(
+                model=self.model_name,
+                prompt_tokens=prompt_tokens,
+                completion_tokens=completion_tokens,
+                cache_read_tokens=cache_read_tokens,
+                cache_write_tokens=cache_write_tokens,
+                response_id=response_id,
+            )
+        )
+
     def merge(self, other: 'Metrics') -> None:
+        """Merge 'other' metrics into this one."""
         self._accumulated_cost += other.accumulated_cost
         self._costs += other._costs
-        self._response_latencies += other._response_latencies
+        # use the property so older picked objects that lack the field won't crash
+        self.token_usages += other.token_usages
+        self.response_latencies += other.response_latencies
 
     def get(self) -> dict:
         """Return the metrics in a dictionary."""
@@ -80,12 +126,14 @@ def get(self) -> dict:
             'response_latencies': [
                 latency.model_dump() for latency in self._response_latencies
             ],
+            'token_usages': [usage.model_dump() for usage in self._token_usages],
         }
 
     def reset(self):
         self._accumulated_cost = 0.0
         self._costs = []
         self._response_latencies = []
+        self._token_usages = []
 
     def log(self):
         """Log the metrics."""

tests/unit/test_llm.py

@@ -2,6 +2,7 @@
 from unittest.mock import MagicMock, patch
 
 import pytest
+from litellm import PromptTokensDetails
 from litellm.exceptions import (
     RateLimitError,
 )
@@ -429,3 +430,62 @@ def test_get_token_count_error_handling(
     mock_logger.error.assert_called_once_with(
         'Error getting token count for\n model gpt-4o\nToken counting failed'
     )
+
+
+@patch('openhands.llm.llm.litellm_completion')
+def test_llm_token_usage(mock_litellm_completion, default_config):
+    # This mock response includes usage details with prompt_tokens,
+    # completion_tokens, prompt_tokens_details.cached_tokens, and model_extra.cache_creation_input_tokens
+    mock_response_1 = {
+        'id': 'test-response-usage',
+        'choices': [{'message': {'content': 'Usage test response'}}],
+        'usage': {
+            'prompt_tokens': 12,
+            'completion_tokens': 3,
+            'prompt_tokens_details': PromptTokensDetails(cached_tokens=2),
+            'model_extra': {'cache_creation_input_tokens': 5},
+        },
+    }
+
+    # Create a second usage scenario to test accumulation and a different response_id
+    mock_response_2 = {
+        'id': 'test-response-usage-2',
+        'choices': [{'message': {'content': 'Second usage test response'}}],
+        'usage': {
+            'prompt_tokens': 7,
+            'completion_tokens': 2,
+            'prompt_tokens_details': PromptTokensDetails(cached_tokens=1),
+            'model_extra': {'cache_creation_input_tokens': 3},
+        },
+    }
+
+    # We'll make mock_litellm_completion return these responses in sequence
+    mock_litellm_completion.side_effect = [mock_response_1, mock_response_2]
+
+    llm = LLM(config=default_config)
+
+    # First call
+    llm.completion(messages=[{'role': 'user', 'content': 'Hello usage!'}])
+
+    # Verify we have exactly one usage record after first call
+    token_usage_list = llm.metrics.get()['token_usages']
+    assert len(token_usage_list) == 1
+    usage_entry_1 = token_usage_list[0]
+    assert usage_entry_1['prompt_tokens'] == 12
+    assert usage_entry_1['completion_tokens'] == 3
+    assert usage_entry_1['cache_read_tokens'] == 2
+    assert usage_entry_1['cache_write_tokens'] == 5
+    assert usage_entry_1['response_id'] == 'test-response-usage'
+
+    # Second call
+    llm.completion(messages=[{'role': 'user', 'content': 'Hello again!'}])
+
+    # Now we expect two usage records total
+    token_usage_list = llm.metrics.get()['token_usages']
+    assert len(token_usage_list) == 2
+    usage_entry_2 = token_usage_list[-1]
+    assert usage_entry_2['prompt_tokens'] == 7
+    assert usage_entry_2['completion_tokens'] == 2
+    assert usage_entry_2['cache_read_tokens'] == 1
+    assert usage_entry_2['cache_write_tokens'] == 3
+    assert usage_entry_2['response_id'] == 'test-response-usage-2'