Prompt caching, token/cost reporting, state monad refactor

Prompt caching, token/cost reporting, state monad refactor

[Arun Isaac]

Hello,

kaagum is a tiny security-focused AI agent written in Guile. Here are
some quick development highlights from last month.

Two big quality-of-life improvements have landed:

kaagum now enables automatic prompt caching with a TTL of 1 hour. On
repeated prompts that share a common prefix, which is typical of a
kaagum session, this can cut costs by up to 90% on the Anthropic API!

kaagum now reports the token usage, context length and session cost to
your ACP client. Keep an eye on your costs.

Internally, kaagum uses TEA (The Elm Architecture) to separate
side-effects from a purely functional core state update function. This
core has now been rewritten using the state monad, simplifying it
further.
https://klaus.systemreboot.net/kaagum/commit/03a0edf0e2f0df29afdded81824c7aa75745fa24/

Cheers!
Arun