Accelerate Goal Builds With A Shared Build Cache

Use this runbook when Goal Rounds on a node spend most of their implementation and Quality time building the target app. Every Round works in an isolated worktree, so without a shared cache each fresh Round pays a cold build. The fix is host toolchain configuration, not Refine configuration: Refine invokes agents with the host’s shell environment, so whatever build caching the target app’s toolchain supports simply starts applying to every Round.

Recovery Rounds drafted from Quality or Governance findings already reuse the source Round’s worktree and its warm build state automatically. This runbook adds cache sharing for fresh Rounds and across Goals.

Pick the cache for the target app’s toolchain

Interpreted stacks (JavaScript/TypeScript, Python, Ruby) usually need nothing: npm, pip, and bundler keep host-global download caches, so a fresh worktree’s dependency install is already warm. Check that first before adding anything.
Compiled stacks need a compiler- or build-level cache configured on the host: sccache for Rust, ccache for C/C++, the Gradle build cache for JVM projects, and equivalents elsewhere. Each worktree keeps its own build output directory — build-tool locking is untouched — while compiled artifacts are shared through the cache.

Ask the user before installing new system packages on the node.

Apply (Rust example — Refine’s own self-hosted development)

Install the cache once per node:
```
cargo install sccache --locked
```
Export it from the shell startup files of the user that runs the node (for example ~/.bashrc):
```
export RUSTC_WRAPPER=sccache
export SCCACHE_CACHE_SIZE=20G
```
Restart the Refine daemon. Refine reads the login-shell environment once per daemon lifetime, so the restart is what picks the exports up — for both the agents Refine spawns and the Quality gate’s supervised proof commands, which inherit the daemon’s own environment.

Verify

Let one Goal Round complete, then inspect the cache tool’s statistics (for sccache, sccache --show-stats). Cache hits should climb on the second and subsequent Rounds that touch the same dependencies. The Quality gate re-runs tests in the worktree the implementation agent already built, so most of its build work short-circuits as well.

Undo

Remove the exports from the shell startup files and restart the daemon. The next agent launch reverts to plain toolchain invocations; the cache tool’s on-disk cache can be deleted at any time.