Custom headers for model connection

[thdvinh]

My workplace hosts an internal model based on openai model. To access it, I need to add a customized header parameter in the request.
How could I config the model connection with custom header with Fast-agent?

[evalstate]

Previous Discord discussion: https://discord.com/channels/1358470293990936787/1358470293990936790/1412695822679933022

Thinking this is a small-ish change to set up in the config file....

[evalstate]

#544
https://fast-agent.ai/models/llm_providers/#common-configuration-format

Will be in the next release.