langsmith: clarifications to messages format #655
+145
−133
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
Preview ID generated: preview-llmcal-1758848807-b95b6b2 |
|
Preview ID generated: preview-llmcal-1759194510-092ba06 |
tanushree-sharma
changed the title
|
Preview ID generated: preview-llmcal-1759195340-f7db8a9 |
|
Preview ID generated: preview-llmcal-1759195522-41a72bb |
hwchase17
reviewed
Sep 30, 2025
| --- | ||
| title: Log custom LLM traces | ||
| sidebarTitle: Log custom LLM traces | ||
| title: Guidelines for logging LLM calls |
There was a problem hiding this comment.
Maybe just "Logging LLM calls"
|
|
||
| * Each message must contain the key `"role"` and `"content"`. | ||
| * `"role"`: `"system" | "user" | "assistant" | "tool"` | ||
| * `"content"`: string |
There was a problem hiding this comment.
The alternative being type?
|
|
||
| * An dict/object containing `"messages"` key with a list of messages in the above format. | ||
| * LangSmith may use additional parameters in this input dict that match OpenAI's [chat completion endpoint](https://platform.openai.com/docs/guides/text?api-mode=chat) for rendering in the trace view, such as a list of available `tools` for the model to call. | ||
| A Python dictionary or TypeScript object containing a `"messages"` key with a list of messages in [LangChain](https://python.langchain.com/docs/concepts/messages), [OpenAI](https://platform.openai.com/docs/api-reference/messages) (chat completions) or [Anthropic](https://docs.anthropic.com/en/api/messages) format. The messages key must be in the top level of the input field. |
There was a problem hiding this comment.
i actually think we should somewhat document these here
| * Each message must contain the key `"role"` and `"content"`. | ||
| * `"role"`: `"system" | "user" | "assistant" | "tool"` | ||
| * `"content"`: string | ||
| * Messages with the `"assistant"` role may contain `"tool_calls"`. These `"tool_calls"` may be in [OpenAI](https://platform.openai.com/docs/guides/function-calling?api-mode=chat) format or [LangChain's format](https://python.langchain.com/api_reference/core/messages/langchain_core.messages.tool.ToolCall.html#langchain_core.messages.tool.ToolCall). |
There was a problem hiding this comment.
same, we should consider documenting these here
jacoblee93
reviewed
Sep 30, 2025
|
|
||
| LangSmith provides special rendering and processing for LLM traces, including token counting (assuming token counts are not available from the model provider) and token-based cost calculation. In order to make the most of this feature, you must log your LLM traces in a specific format. | ||
| <Tip>In order to make the most of LangSmith's LLM trace processing, **we recommend logging your LLM traces in one of the specified formats**. | ||
| If you don't log your LLM traces in the suggested formats, you will still be able to log the data to LangSmith, but it may not be processed or rendered in expected ways. </Tip> |
There was a problem hiding this comment.
A little repetitive, how about view your traces in LangSmith
|
|
||
| If you're using a custom input or output format, you can convert it to a LangSmith compatible format using `process_inputs` and `process_outputs` functions on the [`@traceable` decorator](https://docs.smith.langchain.com/reference/python/run_helpers/langsmith.run_helpers.traceable). Note that these parameters are only available in the Python SDK. | ||
|
|
||
| `process_inputs` and `process_outputs` accept functions that allow you to transform the inputs and outputs of a specific trace before they are logged to LangSmith. They have access to the trace's inputs and outputs, and can return a new dictionary with the processed data. |
There was a problem hiding this comment.
nit: add a JS section with camel cased variants: processInputs and processOutputs
jacoblee93
reviewed
Sep 30, 2025
| class LangSmithOutputs(BaseModel): | ||
| """The output format LangSmith expects.""" | ||
|
|
||
| def process_inputs(inputs: dict) -> dict: |
There was a problem hiding this comment.
Maybe add a real example?
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Goals
Preview deployment: https://langchain-5e9cc07a-preview-llmcal-1759195522-41a72bb.mintlify.app/langsmith/log-llm-trace