openai-messages-token-helper
A helper library for estimating tokens used by messages sent through OpenAI Chat Completions API.
Decision gist · record as of 2026-08-14
Yes, if you are building applications that use OpenAI's Chat Completions API and need to manage token budgets programmatically. The library is straightforward, has low install friction, carries no known vulnerabilities, and solves a real operational problem—preventing token-limit errors by pre-calculating and truncating conversations. Maintenance is aging but the repository is active; use it with the understanding that updates may be infrequent.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires openai and tiktoken to be installed; model name must be recognized or fallback_to_default must be True.
- Low install friction; depends on openai, tiktoken, and pillow.
- Maintenance status is aging—last commit 2025-12-29, 228 days since release—but the repository is active and not archived.
License · maintenance · safety
permissive license (permissive) — Licensed under MIT (permissive), so you can use, modify, and distribute freely with minimal restrictions.
last release 2025-12-29 (228 days) · last repo commit 2025-12-29 · 34 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 86,761 downloads/mo, #13,840 on PyPI
Alternatives
Verify before relying
from openai_messages_token_helper import build_messages
messages = build_messages(
model="gpt-4",
system_prompt="You are a helpful assistant.",
new_user_content="Hello",
past_messages=[]
)- Whether the package handles all current OpenAI model variants or only a fixed set.
- Performance characteristics when processing large message histories or many images in a single call.
- Whether token counts match OpenAI's actual billing exactly or are estimates.
What it is and what it does
This package wraps OpenAI's tokenization logic to help you stay within token budgets when building chat conversations. It provides functions to count tokens in individual messages, images (for GPT-4 vision), and tool definitions, then uses those counts to automatically truncate old messages from a conversation history so the final message list fits within a model's token limit.
You supply a system prompt, optional few-shot examples, past messages, and a new user message, along with a target token budget and model name. The library calculates the token cost of each component using tiktoken for text and Pillow for image dimensions, then drops old messages from the history until everything fits. It also supports Azure OpenAI model names and can fall back to default limits if a model is unrecognized.
Use it for
- Automatically truncate chat history to fit within a model's context window before sending to the OpenAI API.
- Calculate token costs for images in GPT-4 vision requests to budget vision-enabled conversations.
- Build few-shot prompts with known token budgets, ensuring examples fit alongside user messages.
- Estimate API costs by counting tokens before making requests to OpenAI.
- Handle tool definitions and tool-choice parameters in token calculations for function-calling workflows.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you are building applications that use OpenAI's Chat Completions API and need to manage token budgets programmatically.
The library is straightforward, has low install friction, carries no known vulnerabilities, and solves a real operational problem—preventing token-limit errors by pre-calculating and truncating conversations. Maintenance is aging but the repository is active; use it with the understanding that updates may be infrequent.
Install
openai-messages-token-helper on PyPI
Before you install
Low install friction; depends on openai, tiktoken, and pillow. Maintenance status is aging—last commit 2025-12-29, 228 days since release—but the repository is active and not archived. Supports Python 3.9, 3.10, and 3.11.
Requires openai and tiktoken to be installed; model name must be recognized or fallback_to_default must be True.
License in practice
Licensed under MIT (permissive), so you can use, modify, and distribute freely with minimal restrictions.
Quickstart
from openai_messages_token_helper import build_messages
messages = build_messages(
model="gpt-4",
system_prompt="You are a helpful assistant.",
new_user_content="Hello",
past_messages=[]
)Verify before relying
- Whether the package handles all current OpenAI model variants or only a fixed set.
- Performance characteristics when processing large message histories or many images in a single call.
- Whether token counts match OpenAI's actual billing exactly or are estimates.
Package facts
| License | permissive license permissive |
| Python support | Supports the current Python release >=3.9 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 3 packagesopenaitiktokenpillow |
| Maintenance | Aging 228 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 86,761 / month, #13,840 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Framework :: PytestLicense :: OSI Approved :: MIT LicenseProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.9 |
Evidence: openai_messages_token_helper-0.1.13-py3-none-any.whl
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