Model Cost Sync - Ability for an older langfuse version to sync cost with newer prices

[rvndbalaji]

Describe the feature or potential improvement

Model Cost Sync - Ability for an older langfuse version to sync cost with newer prices

Hi , assume the following conditions

1. Im on an older langfuse version, say V1 with model prices for that version running in the instance
2. A new model releases that has updated costs, or an older model's pricing was changed

Without upgrading the entire langfuse instance - which might not be feasible immediately or might take a week or so -
I would like the ability to "sync" brand new prices into an older instance.

We may have the following options

1. Introduce a "sync" mechanism which fetches and upserts prices by checking the following URL - This can be exposed as an endpoint as well - https://github.com/langfuse/langfuse/blob/main/worker/src/constants/default-model-prices.json
2. Move the default-model prices to the SDK so that updates to the SDK is sufficient to have latest prices
3. Provide a "json" option where I can copy paste from the above json and have Langfuse update it automatically

Right now we're finding it very difficult and manually updating the prices from the above json (which is also very tedious given the UI does not accept the same json)

PRODUCTION INCIDENT - USE CASE

1. We added Claude 4.6 many months ago which had the tier based pricing for double. the price >200 context tokens
   We did this manually without having to upgrade langfuse
2. Anthropic dropped this large context pricing months later
3. We upgraded Langfuse but forgot about the large context tier model
4. This caused our Langfuse to show $ 10,000 more than what GCP Billing showed us.
5. Caused confusion with leadership when we corrected this and the prices dropped on report

Additional information

No response

FYI @marcklingen @CodeCLS @hassiebp

[hassiebp]

Thanks for raising this! We have the decoupling of model price updates from Langfuse platform releases for self hosters on our short-term roadmap