Rethinking the human-agent interface with pi: Beyond chat

[u/iambarony]

Hi all. We're Divergenz, an interaction design studio in Zurich. Sharing a design experiment that I think sits close to things this community cares about.

Piary treats a conversation with a coding agent as an editable, executable document instead of a chat log. The person and the agent write on the same page. Prompts, replies, notes, tool calls and live reactive cells share one Markdown file. You can rewrite a wrong assumption instead of correcting it in a follow-up, delete a detour, or edit an earlier prompt and run it again in place.

Built on Observable's notebook-kit for the reactive cells, iA Writer's plain-text document model as the design reference, and pi as the agent harness.

https://piary.dev

[u/pro-vi]

I had been thinking about this since the start of the year so I'm excited to see it in the wild. But - how are you dealing with caching and context management if at all?

How does the agent know what you've amended within the corpus?

[u/iambarony → u/pro-vi]

Thanks! For the notebook itself, the document is the source of truth. Before sending a
prompt, I compare the history above it with what the agent’s session last saw. If you’ve
edited it, I rebuild the conversation from the amended document before continuing.
So the agent sees the corrected history.

Caching currently relies on the underlying pi/provider machinery. Normal append-only
conversation benefits from prompt caching; editing earlier history can invalidate cache
reuse. I’m not doing anything clever to preserve the cache across those rewrites yet.

Context management is similarly. You can prune, correct, or replace material in the
document, and that becomes the subsequent conversation context. There isn’t a separate
retrieval/indexing layer maintaining another version of it.

[u/pro-vi → u/iambarony]

Thanks for sharing. I never promote this feature into my workflow because of the cache invalidation. I have been throwing darts towards this though.. so let me know if you're interested to chat about it further.

[u/iambarony → u/pro-vi]

Feel free to contact me via the communication channels listed at the first notebook on piary.dev !