f84b534248
## Description
OpenRouter returns `cost` and `cost_details` in its API response `usage`
object, providing the actual cost of each API call. Currently,
`_create_usage_metadata()` only extracts token counts and drops these
cost fields.
This PR surfaces both `cost` and `cost_details` in `response_metadata`
for both non-streaming and streaming paths, allowing users to access
actual API costs directly from the response without manual estimation
from token counts.
**Example response from OpenRouter:**
```json
{
"usage": {
"prompt_tokens": 100,
"completion_tokens": 50,
"cost": 0.000075,
"cost_details": {
"upstream_inference_cost": 0.00007745,
"upstream_inference_prompt_cost": 0.00000895,
"upstream_inference_completions_cost": 0.0000685
}
}
}
```
**After this change:**
```python
result = chat.invoke("hello")
result.response_metadata["cost"] # 0.000075
result.response_metadata["cost_details"] # {...}
```
## Changes
- **`_create_chat_result`**: Surface `cost` and `cost_details` from
`token_usage` into `response_metadata` (non-streaming)
- **`_convert_chunk_to_message_chunk`**: Same for streaming
`AIMessageChunk`
- Added `PLR0912` to `noqa` comments (new branches pushed count over
threshold)
- Added two unit tests: one verifying cost fields are present when
returned, one verifying they're absent when not in usage
## Issue
N/A — discovered while integrating OpenRouter in a production pipeline.
The cost data is already returned by the API but was being silently
dropped.
## Dependencies
None.
## Twitter handle
@hamza_kyamanywa
---------
Co-authored-by: Mason Daugherty <mason@langchain.dev>
Packages
Important
This repository is structured as a monorepo, with various packages located in this libs/ directory. Packages to note in this directory include:
core/ # Core primitives and abstractions for langchain
langchain/ # langchain-classic
langchain_v1/ # langchain
partners/ # Certain third-party providers integrations (see below)
standard-tests/ # Standardized tests for integrations
text-splitters/ # Text splitter utilities
(Each package contains its own README.md file with specific details about that package.)
Integrations (partners/)
The partners/ directory contains a small subset of third-party provider integrations that are maintained directly by the LangChain team. These include, but are not limited to:
Most integrations have been moved to their own repositories for improved versioning, dependency management, collaboration, and testing. This includes packages from popular providers such as Google and AWS. Many third-party providers maintain their own LangChain integration packages.
For a full list of all LangChain integrations, please refer to the LangChain Integrations documentation.