# Design archive

[Documentation](../README.md)

These documents preserve decisions, reviews, spikes, and implementation history. They are not the authoritative description of current user behavior; use the [guides](../README.md#guides) and [reference](../README.md#reference) for that.

## Subagent design history

- [Request/response design](subagents/interface-design.md) — accepted architecture and completed implementation iterations.
- [Design review](subagents/design-review.md) — issues that drove preflight, task preservation, policy, fingerprint, and response revisions.
- [Pi SDK spike findings](subagents/sdk-spike-findings.md) — historical 0.80.6 investigation; its harness was removed after findings were productized.

## Project planning history

- [0.4 roadmap and implementation log](roadmap-0.4-archive.md)

The current exported semantics are in the [subagent adapter contract](../reference/subagent-adapter.md); forward-looking work is in the [roadmap](../development/roadmap.md).