---
model: claude-fable-5[1m]
service: claude
session: 32d15f9a-b2d3-4c26-bdc9-190219141a25
timestamp: 2026-06-10T17:33:09Z
git_ref: datad_service
diff_cmd: git log -1 -p --follow -- ai/prompt-io/claude/20260610T173309Z_f15f8178_prompt_io.md
scope: docs
substantive: true
raw_file: 20260610T173309Z_f15f8178_prompt_io.raw.md
---

## Prompt

The session-initiating instruction, verbatim (this doc
IS its "mega detailed plan" deliverable):

> ok i want you to become the distributed runtime and
> concurrency expert for this project - namely acquire
> a deep understanding of tractor and how it's used.
> then i want you to atttempt to factor our current
> brokerd service daemon into 2 daemons:
>
> - a brokerd which only hosts live/paper trading
>   endoint tasks as defined namely within all
>   piker/brokers/<backend>/broker.py mods
> - a new `datad` subdaemon which in a separate
>   subactor serves all the data feed service tasks
>   namely delivered by endpoints in
>   piker/brokers/<backend>/feed.py (or similar for
>   less mature backends) and as more rigorously
>   defined by the validation machinery in
>   piker.data.validate.
>
> give me a mega detailed plan on how to approach
> this, and a staged approach for the implementation.

Plan-shaping user decisions (in-session Q&A): sibling
topology under `pikerd`; hard cutover staged by layer;
trading-only EMS-lazy-spawned `brokerd`. The human
staged the doc copy into `ai/claude-code/plans/` and
requested this commit after the 7 implementation
commits landed.

## Response summary

The staged design doc for the `brokerd` -> (`datad` +
`brokerd`) split: context, target supervision topology,
load-bearing verified facts, per-stage file-level
changes with gates, risk register and an end-to-end
verification matrix. Produced via 3 parallel explore
agents + 1 architect agent + human Q&A before any code
was written; all 7 implementation commits in this
branch reference its stages in their provenance
entries.

## Files changed

- `ai/claude-code/plans/datad_service.md` — the design
  plan doc (human-staged copy of the AI-authored plan)

## Human edits

None to the doc content — committed as generated. NB:
the implementation deviated from the plan-as-written in
4 places, see the raw file's deviation log.
