Now returns (`_iter`, `tokens`, `indices`, token_counts`). The
`token_counts` are calculated directly during tokenization, which is
more accurate and efficient than splitting strings later.
## Description
Fixes#31227 - Resolves the issue where `OpenAIEmbeddings` exceeds
OpenAI's 300,000 token per request limit, causing 400 BadRequest errors.
## Problem
When embedding large document sets, LangChain would send batches
containing more than 300,000 tokens in a single API request, causing
this error:
```
openai.BadRequestError: Error code: 400 - {'error': {'message': 'Requested 673477 tokens, max 300000 tokens per request'}}
```
The issue occurred because:
- The code chunks texts by `embedding_ctx_length` (8191 tokens per
chunk)
- Then batches chunks by `chunk_size` (default 1000 chunks per request)
- **But didn't check**: Total tokens per batch against OpenAI's 300k
limit
- Result: `1000 chunks × 8191 tokens = 8,191,000 tokens` → Exceeds
limit!
## Solution
This PR implements dynamic batching that respects the 300k token limit:
1. **Added constant**: `MAX_TOKENS_PER_REQUEST = 300000`
2. **Track token counts**: Calculate actual tokens for each chunk
3. **Dynamic batching**: Instead of fixed `chunk_size` batches,
accumulate chunks until approaching the 300k limit
4. **Applied to both sync and async**: Fixed both
`_get_len_safe_embeddings` and `_aget_len_safe_embeddings`
## Changes
- Modified `langchain_openai/embeddings/base.py`:
- Added `MAX_TOKENS_PER_REQUEST` constant
- Replaced fixed-size batching with token-aware dynamic batching
- Applied to both sync (line ~478) and async (line ~527) methods
- Added test in `tests/unit_tests/embeddings/test_base.py`:
- `test_embeddings_respects_token_limit()` - Verifies large document
sets are properly batched
## Testing
All existing tests pass (280 passed, 4 xfailed, 1 xpassed).
New test verifies:
- Large document sets (500 texts × 1000 tokens = 500k tokens) are split
into multiple API calls
- Each API call respects the 300k token limit
## Usage
After this fix, users can embed large document sets without errors:
```python
from langchain_openai import OpenAIEmbeddings
from langchain_chroma import Chroma
from langchain_text_splitters import CharacterTextSplitter
# This will now work without exceeding token limits
embeddings = OpenAIEmbeddings()
documents = CharacterTextSplitter().split_documents(large_documents)
Chroma.from_documents(documents, embeddings)
```
Resolves#31227
---------
Co-authored-by: Kaparthy Reddy <kaparthyreddy@Kaparthys-MacBook-Air.local>
Co-authored-by: Chester Curme <chester.curme@gmail.com>
Co-authored-by: Mason Daugherty <mason@langchain.dev>
Co-authored-by: Mason Daugherty <github@mdrxy.com>
Largely:
- Remove explicit `"Default is x"` since new refs show default inferred
from sig
- Inline code (useful for eventual parsing)
- Fix code block rendering (indentations)
