agent: builder model: opus max_turns: 100 budget_usd: 25 —
Score: self-hosting lane; the last step of the To build list of #1012 that changes the compiler. Preconditions met (architect, 2026-10-31): step 1 (1c72e8b9), step 2 (51b0838a, NK1264/NK1265) and step 4 (k3a2, 829ce635) are on origin/develop, so this commit writes Fixes #1012. Step 2’s tests a_foreign_impl_keeping_beyond_the_column_is_refused and a_trait_column_change_warns must stay green.
D17 covers every by-value parameter, code or data (ADR-094 D2 does not tell them apart): by value no longer means kept. Step 1 kept today’s by-value seed for data parameters of a trait method, because the lowered host traits in crates/nikaia-std/src/tools/*.nika are implemented only in Rust, and the column moving from kept to run moves their signatures (String to &str, an owned value to a borrow). Known by-value, non-Copy data parameters of host traits (re-grep): hole(text: String), crate_root(name: String), parse_unit(package: String?), emit_unit(provenance: Provenance), absorb(into: Ledger, other: Ledger), two Symbol parameters.
crates/nikaia/src/contracts/keeps.rs: drop the data seed of the trait node; data parameters get the same edge pairs as fn parameters (step 1).check/host.rs, emit/host.rs, project.rs, modules.rs, comptime_run.rs, build_time.rs, fold_bound.rs, emit/seeds.rs, check/core.rs, contracts/keeps.rs and contracts/sync.rs (step 2 added impl lookups there) (grep impl .* for against the trait names of tools/*.nika); each takes the signature its lowered trait now has, and its callers in Rust follow. A Rust impl that really keeps a parameter the column now runs (stores the String): stop, Found: with the trait method and the impl. The column is not widened from Rust (D17: impls in Rust are not evidence).lower-std fixpoint clean. Test in tests/compiler/tests/ (+ .stdout): a trait method taking text: String that its only impl reads, called through a bound by a caller that uses its string after the call and with a borrowed one, prints both; a sibling row where a local impl stores the string keeps the column (the caller’s string moves). Commit contracts: a trait method's data parameter is a view unless its package's impls keep it (#1012); Fixes #1012.The test passes through nikaia test, the #1012 tests of steps 1-2 still pass, cargo build --profile fast -p nikaia, the it filter contracts and the guard set of .claude/agents/builder.md are green; pushed. Changelog: one line (a trait method’s by-value data parameter is borrowed when no impl in its package keeps it).
An edit outside crates/nikaia/src/contracts/keeps.rs, the Rust host impls named above and their callers, crates/nikaia-std/src/tools/*.nika and their lowering, and the new test; a Rust impl keeps a parameter the column runs; an error in another agent’s file.
Not yours, never stage: every file git status shows modified or untracked at your start, and every docs/briefs/* file except your report.
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.std or the toolchain lacks stops the work: no code around it unless an ADR or Part I-III refuses it (name it). Else Result: blocked, Found: gap + probe, Needs: owner decision (CLAUDE.md, A missing form stops the work).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.Pushed: line names the pushed sha. A report without a Pushed: line, or with a placeholder left in (TC, DISK), is not done and cuts the batch (k3a1 2026-10-29: Result: done, nothing committed)./home/user/Nikaia/docs/briefs/b1012c-trait-column-data.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 (redesign) for a brief with Shape: redesign and no Convert: line). 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 process event such as another session resetting or rewriting your files is no Found:, it goes under Needs: (m3a 2026-10-28); 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:, nor a test’s expected .stdout/.stderr taken from what the program really prints where the brief’s sketch of it was short or wrong, b934 2026-10-29: say so in Body:, nor a lowering that follows the ADR governing it where the brief’s expected lowering contradicts that ADR, b933 2026-10-29: name the ADR in Body:, nor re-keying an allow-list entry (KNOWN) whose hash changed for the same program and the same reason, b-fixforward-sweep2 2026-10-28: say so 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