agent: builder model: opus max_turns: 120 budget_usd: 25 —
sysroot.rs into Nikaia (Part #125)Score: self-hosting lane (docs/priorities.md, owner’s direction 2026-10-27: moves first, largest Rust files first; #125, docs/selfhosting-plan.md Large files 2, row S2). S=2 (~445 Rust lines, converter draft 90%; also builds the std::fs bytes probe P3 and P4 wait for), C~4-6 M (comparable: P2, e51e3e2).
sysroot.rs: Sysroot paths, std_modules, tool_modules, nika_in, cpu_levels and the parsing half of native_cpu, tools_sources, Package with committed, inlined, contains, drift, stale, pack, unpack, LoweredBefore key, get, put, the interface/file_key keys of lower_tools_files_cached. Target: new crates/nikaia-std/src/tools/sysroot_cache.nika (std::fs reads, writes, read_dir, as sources.nika). Host added: sha256_hex(ref Vec[u8]) -> String (std has no SHA-256), rustc_cpus(triple, args) -> String throws, use_entry(dir) and user_cache_dir() (orchestrator::cache), unique_beside(path) (comptime_run); the ASKED memo of native_cpu stays Rust around the Nikaia parse.crates/nikaia/src/sysroot.rs: struct Sysroot :90, std_modules :135, tool_modules :162, nika_in :171, cpu_levels :227, native_cpu :250, tools_sources :460, lower_tools_files_cached :544 (interface :599-619, file_key :620-627), struct Package :783-878, struct LoweredBefore :1331, key :1373, get :1390, put :1398, mod tests :1420 on (Rust tests of LoweredBefore: they keep calling the Rust wrappers and stay passing; they are the key-stability check).std::fs in tools/*.nika reads and writes bytes. Build it here first: a small tests/compiler program, and if it fails, that is a compiler/std fix as its own commit before the move.Debug text ({build:?}{provenance:?}{facts_reusable}, {own:?}): Rust computes those strings and passes them in as String; Nikaia builds the same bytes in the same order (part: u64 little-endian length, then the bytes; key: parts ended by 0). The draft wrote interface as one line of closures over a mut Vec[u8]: write a nested or module fn instead. without_bodies is S1’s and stays Rust: pass its results in.lower_std*, lower_tools* runs, in_parallel, Phases, Sysroot::resolve, rlib_cache, COMPILER_IDENTITY, rustc_cpus, tools_build, impl Display for Package, mod tests.std::fs bytes probe (above), committed as its own test.rs2nika --profile check --file), report --score under Rs2nika:. Move the listed code into sysroot_cache.nika (prefix sysroot_ where where.nika finds a clash), with the doc comments. sysroot.rs calls the lowered functions; the moved Rust is deleted. lower-std: only the new lowered file and its index lines change; then a second lower-std reuses every file from the cache (report reused under Tests:).sysroot_cache.nika’s row to scripts/self_hosting.py (as project_check.nika’s), mark S2 built in the plan’s table (one line); report the self-hosting % under Tests:.A lowering defect met is fixed in the compiler as its own commit with a test (Fix, do not work around, CLAUDE.md); if it is more than one step, stop and report it under Needs:.
nikaia test tests/compiler --both-settings; cargo test -p nikaia --lib sysroot::; it tests filtered on sysroot lower_std native cpu package drift; the guard set of .claude/agents/builder.md; clippy clean; lower-std fixpoint. Commit sysroot: paths, package and cache keys into Nikaia (S2), Part: #125. Changelog: none (a move).
An open design choice; a cache key that would change; a .stderr that would change; an error in another agent’s file.
Read docs/builder-facts.md.
docs/builder-facts.md first. develop in the main checkout; git status at start: other agents’ uncommitted files are not yours, never touch or stage them.git add <files> only; commit after each step; git push origin develop fast-forward, no rebase (rejected: report Pushed: rejected, go on committing).cargo fmt, cargo clippy --all-targets -- -D warnings, scripts/pre-push-check.sh, and the gate of .claude/agents/builder.md (#852).CHANGELOG.md, badges; no new NK code. New tests in Nikaia only; never the full suite. No foreground sleep, no polling; scripts in files.NIKAIA_CACHE_LIMIT=2G; at most two clones with target/ in the machine; delete your own clone’s target/ and target/release/nikaia-scratch at the end; report GB freed./home/user/Nikaia/docs/briefs/s2-sysroot-cache.md.report.md)Fields of docs/architect.md, Briefs and reports: Result: done|noop|partial|blocked (the bare word alone on that line: Result: done, never a summary after it, which cuts the batch, b869a 2026-10-27; Owner: is a question for the owner or none, never a role), Files, Commit, Body (optional, one paragraph for the commit message), Fixes, Pushed, Tests, Gate (green|red), Deviation, Found, Needs, Changelog, Owner, Disk freed, and for a move Rs2nika: (the kept N of M lines of rs2nika --score, then the three costliest hand edits; none for a task that moves no Rust). none where nothing, and then the bare word: Deviation: none (a note) cuts the batch (batch.nika compares exactly); a note goes into the commit message. Found: is only for a defect outside your change (it cuts the batch); a converter draft that came out wrong is no Found:, it is one of the costliest edits under Rs2nika:, which the converter lane reads (e12-4b 2026-10-27); how you solved your own step goes into the commit message. Deviation: is only a step of the brief built otherwise than written or not built (a choice the brief left to you, such as keep what X needs and say so, is no deviation: it goes into the commit message; nor is building two steps in one commit when every step is built, e12-3a 2026-10-27, nor a step another commit on develop already built, shown by your test failing with that commit’s change reverted, b889 2026-10-27: name the commit in Body:); how you verified (e.g. a test not run against the unfixed compiler) goes under Tests:. A noop says why under Tests: (what was probed), not under Deviation:. Final answer, one line: done <sha>, report <path> (or BLOCKED: ... / PUSH REJECTED ...).
Attribution: Co-Authored-By: Claude Opus 5.5 noreply@anthropic.com Claude-Session: https://claude.ai/code/session_01GFeMqxRbtUMiGVyDMxsvEq