Sample code on how to use AWS Titan and other Open Source models from BedRock such as Mistral and LLama. You will need to request access via Model Access
Also see my bedrock links
$ aws bedrock list-foundation-models | jq '.modelSummaries[]|.modelId' | egrep '(titan|llama|mistral)'
"amazon.titan-tg1-large"
"amazon.titan-embed-g1-text-02"
"amazon.titan-text-lite-v1:0:4k"
"amazon.titan-text-lite-v1"
"amazon.titan-text-express-v1:0:8k"
"amazon.titan-text-express-v1"
"amazon.titan-embed-text-v1:2:8k"
"amazon.titan-embed-text-v1"
"amazon.titan-embed-image-v1:0"
"amazon.titan-embed-image-v1"
"amazon.titan-image-generator-v1:0"
"amazon.titan-image-generator-v1"
"meta.llama2-13b-chat-v1:0:4k"
"meta.llama2-13b-chat-v1"
"meta.llama2-70b-chat-v1:0:4k"
"meta.llama2-70b-chat-v1"
"meta.llama2-13b-v1:0:4k"
"meta.llama2-13b-v1"
"meta.llama2-70b-v1:0:4k"
"meta.llama2-70b-v1"
"mistral.mistral-7b-instruct-v0:2"
"mistral.mixtral-8x7b-instruct-v0:1"