From 39bcf2b3b8f07d05c599f9c11d1fda47485c9b50 Mon Sep 17 00:00:00 2001
From: Tom Wright <tom@inflatablecookie.com>
Date: Tue, 20 Oct 2026 18:40:42 +0100
Subject: [PATCH] Build Rust through Oxide

Rust selectors use oxide (Cargo with managed, budgeted build storage off
the laptop SSD); rust:check:cargo, rust:clippy:cargo and rust:test:cargo
are the plain-Cargo fallback. AGENTS.md gains the oxide init block and
points agents at oxide. Templates and consumer instructions unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 AGENTS.md   | 23 ++++++++++++++++++-----
 effigy.toml | 20 +++++++++++++-------
 2 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/AGENTS.md b/AGENTS.md
index 065be0fc..536a75e5 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -69,8 +69,10 @@ covers how to route by job. What is specific to Underlay:
   there, so its warnings are not a fresh regression signal.
 - Northstar AGENTS reviews use `effigy qa:docs:agent-defaults` here. This repo
   does not ship `check:agent-instructions`.
-- Fall back to raw `cargo`, `bun`, or `vitest` only when the needed operation is
-  not represented in `effigy.toml`.
+- Fall back to raw `oxide`, `bun`, or `vitest` only when the needed operation is
+  not represented in `effigy.toml`. Rust goes through `oxide` (Cargo with
+  managed build storage), not `cargo`; `rust:check:cargo`, `rust:clippy:cargo`
+  and `rust:test:cargo` are the plain-Cargo fallback if `oxide` misbehaves.
 - First-time local bring-up from outside this repo:
   `effigy bootstrap git@github.com:inflatable-cookie/underlay.git`
 
@@ -81,11 +83,11 @@ for the change and run each required check once; do not repeat a passing run.
 
 ```bash
 effigy health            # cheap baseline
-effigy rust:check        # cargo check --workspace --all-features
+effigy rust:check        # oxide check --workspace --all-features
 effigy rust:clippy       # denies warnings
 effigy rust:test         # filter {args} to the touched crate/package
-effigy fmt:rust:check    # cargo fmt --all --check; read-only
-effigy fmt:rust          # cargo fmt --all; mutates the workspace
+effigy fmt:rust:check    # oxide fmt --all --check; read-only
+effigy fmt:rust          # oxide fmt --all; mutates the workspace
 effigy fmt:ts -- ts/src/client/format.ts        # format the named TypeScript files
 effigy fmt:ts:check -- ts/src/client/format.ts  # read-only formatting check
 effigy test:unit         # vitest, filter {args} to the touched code
@@ -168,3 +170,14 @@ Reference docs:
 - Graph workflows: `docs/guides/076-code-graph-and-agent-workflows.md`
 - JSON contracts: `docs/guides/017-json-output-contracts.md`
 <!-- END EFFIGY AGENT CONTRACT -->
+
+<!-- oxide:begin -->
+## Rust commands: use `oxide`
+
+- Write `oxide` wherever you would write `cargo`: `oxide check`, `oxide test`, `oxide run -- <args>`, `oxide add <crate>`.
+- Profiles: `quick` (default), `--profile debug` for a debugger, `--release`. Oxide places build output, so it refuses `--target-dir`.
+- A `waiting for …` line means another build holds a slot; let it wait. `oxide status` shows the pool, slots and waits.
+- Use `oxide clean`, not `cargo clean`.
+
+Managed by `oxide init`; edits between these markers are replaced.
+<!-- oxide:end -->
diff --git a/effigy.toml b/effigy.toml
index 265bed87..56722465 100644
--- a/effigy.toml
+++ b/effigy.toml
@@ -34,7 +34,7 @@ setup = ["bootstrap:deps"]
 [tasks]
 "bootstrap:deps" = [
     "bun install",
-    "cargo fetch",
+    "oxide fetch",
 ]
 
 check = "cd {repo} && bun x svelte-check --tsconfig ./ts/tsconfig.json"
@@ -47,12 +47,18 @@ check = "cd {repo} && bun x svelte-check --tsconfig ./ts/tsconfig.json"
 "check:workspace-shape" = "cd {repo} && bun x vitest run ts/tests/tools/workspace-shape.test.ts ts/tests/tools/merge-pr-closeout-cleanup.test.ts"
 "check:env-authority" = "cd {repo} && bun x vitest run ts/tests/tools/env-authority.test.ts"
 "check:consumer-conformance-fixtures" = "cd {repo} && bash scripts/test-consumer-conformance-fixtures.sh"
-"rust:build" = "cd {repo} && cargo build --workspace"
-"rust:check" = "cd {repo} && cargo check --workspace --all-features"
-"rust:clippy" = "cd {repo} && cargo clippy --workspace --all-targets -- -D warnings"
-"rust:test" = "cd {repo} && cargo test --workspace --all-features"
-"fmt:rust" = "cd {repo} && cargo fmt --all"
-"fmt:rust:check" = "cd {repo} && cargo fmt --all --check"
+# Rust goes through Oxide (Cargo with managed, budgeted build storage off the
+# laptop SSD). The `:cargo` selectors are the plain-Cargo fallback if Oxide
+# misbehaves; they write to the checkout's `target/`.
+"rust:build" = "cd {repo} && oxide build --workspace"
+"rust:check" = "cd {repo} && oxide check --workspace --all-features"
+"rust:clippy" = "cd {repo} && oxide clippy --workspace --all-targets -- -D warnings"
+"rust:test" = "cd {repo} && oxide test --workspace --all-features"
+"rust:check:cargo" = "cd {repo} && cargo check --workspace --all-features"
+"rust:clippy:cargo" = "cd {repo} && cargo clippy --workspace --all-targets -- -D warnings"
+"rust:test:cargo" = "cd {repo} && cargo test --workspace --all-features"
+"fmt:rust" = "cd {repo} && oxide fmt --all"
+"fmt:rust:check" = "cd {repo} && oxide fmt --all --check"
 "fmt:ts" = "cd {repo} && ./node_modules/.bin/prettier --write {args}"
 "fmt:ts:check" = "cd {repo} && ./node_modules/.bin/prettier --check {args}"
 "test:unit" = "cd {repo} && bun x vitest run {args}"