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agent: builder model: sonnet max_turns: 45 budget_usd: 8 effort: low —

Brief: C1c, LedgerOps::lookup into ledger_items.nika (Part #125)

Score: self-hosting lane, plan row C1 of docs/selfhosting-plan.md (third and last part; C1a 5bd603f3, C1b 547e6462). Small: S=1, C~0.5 M. It waited on #1107 (b26, a062b45a): a ref T? map view unwrapped by ?? now stays a view for a struct that does not copy, and FnContract does not copy (ty.nika:1082, Vec fields). Touches no file of K3b (comptime_run.rs, comptime_bundle.nika).

Cut: crates/nikaia/src/contracts/mod.rs:542-546 Convert: –profile check Shape: faithful

Facts: Where things live, Traps already met, Moving Rust into Nikaia, Commands

Facts

• What moves: the body of lookup (impl LedgerOps for Ledger, contracts/mod.rs:542, doc comment :523-541 carried over to the Nikaia function). New in ledger_items.nika, beside ledger_items_stored (:488): pub fn ledger_items_lookup(ledger: ref Ledger, name: String) -> (String, ref FnContract)? — let contract: ref FnContract = ledger.functions.get(name) ?? return null, then return (name.clone(), contract) (Ledger and FnContract are ty.nika :1240 / :1082, functions a BTreeMap[String, FnContract] :1265). Write name: String, not ref String (NK1261).
• Probe (architect, e1a88e49): this exact shape with a non-copy struct in a BTreeMap, read back through let (k, c) = lookup(l, "a") ?? return, runs and prints the right fields; a missing key gives null.
• Rust keeps the trait method and its signature fn lookup(&self, name: &str) -> Option<(String, &FnContract)> as a one-line forward: nikaia_std::tools::ledger_items::ledger_items_lookup(self, name) (adapt only the argument form the lowering asks for: &str or &String). The 46 callers in 19 files (scripts/where.nika -- lookup) are not touched.
• #1060 guard: after lower-std, only lowered/ledger_items.rs and lowered.rs are yours. lowered/emit_core_leaves.rs differs in the tree from another agent’s uncommitted emit_core_leaves.nika: neither stage nor restore it.
• Do not touch: crates/rs2nika/**, docs/briefs/* but your report, the uncommitted files git status shows at start.

To build

1. ledger_items_lookup in ledger_items.nika, the Rust forward, lower-std and its fixpoint. Tests: cargo test -p nikaia --lib contracts::, cargo test -p nikaia --test it -- throws ledger contract trust prelude (anchored grep -E '^test result:|FAILED|panicked'). Plan row C1: C1c built, row closed (what stays Rust: the rest of infer_package_noted, evaluate_defaults, set_default, computed_literal); self-hosting share in Body:. Commit contracts: lookup moves into ledger_items.nika (C1c), Part: #125.

Rules

• Read docs/builder-facts.md first. develop in the main checkout; other agents’ uncommitted files are not yours: never touch or stage them.
• Commit locally after each step with target/fast/nikaia run scripts/commit.nika -- REPORT (it adds exactly the report’s Files:); the driver pushes.
• Before committing, cheap checks only: cargo build --profile fast -p nikaia, lower-std and its fixpoint when a tools/*.nika changed, cargo fmt, cargo clippy --all-targets -- -D warnings, scripts/pre-push-check.sh, the tests the brief names and the ones your change touches.
• Version lines, CHANGELOG.md, badges and NK codes are the supervisor’s. New tests in Nikaia only.
• A form Nikaia, std or the toolchain lacks stops the work, unless an ADR or Part I-III refuses it (name it): Result: blocked, Found: the gap with a probe, Needs: architect decision.
• Disk: NIKAIA_CACHE_LIMIT=2G; at the end delete your own clone’s target/ and target/release/nikaia-scratch.
• No cause after about 40 turns: stop, Result: partial with what you ruled out, the probe, and the suspected file and function.

Report (at most 15 lines, to exactly /home/user/Nikaia/docs/briefs/c1c-ledger-lookup.md.report.md)

Fields of docs/architect.md, Briefs and reports: Result, Files, Commit, Body (optional), Fixes, Pushed, Tests, Gate, Deviation, Found, Needs, Changelog, Owner (a question for the owner), Disk freed, for a move Rs2nika: (the kept N of M lines of rs2nika --score and the three costliest hand edits, else none), and last Attribution: with your commit trailer lines below it.

• Result:, Gate: (green or red <check>), Deviation:, Found: and the other fields with nothing to say hold the bare word: done, none. Anything after it reads as content.
• Deviation: only for a step of the brief built otherwise than written, or not built. Found: only for a defect outside your change. Everything else (your choices, how you solved the step, why a test’s expected output changed) goes into Body:; how you verified goes into Tests:.
• Final answer, one line: done <sha>, report <path> (or BLOCKED: ... / PUSH REJECTED ...).

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