agent: builder model: opus max_turns: 120 budget_usd: 30 —

Brief: type arguments at a call reached by a path (`json::read[Contact](bytes)`, ADR-grammar-2 D11)

Score: owner’s direction (2026-10-31): #1019 (json::read[T]) waits on exactly this. #859 steps 2 and 8 are built (a104be7, 0.0.1319), but f[T](…) is type arguments only where f is a generic function declared in this file; a callee reached by a path (another module, std, a package) still reads [T] as a value and gives NK1230. That is a defect (kind 3): ADR-grammar-2 D11 names json::read[Contact](bytes) itself.

Problem (probe it with `target/fast/nikaia check` at your start)

Find a generic function in std or write one in a second module of a small project (fn pick[T](n: i64) -> String { T::name }), then call it as mod::pick[User](1) / std::…::f[T](…). Expected today: NK1230 (a type where a value belongs). Confirm and say what you found.

Decision (accepted records, no owner decision needed)

ADR-330 D9 (f[T](): the types fill the type parameters in order; a function’s form, a method’s x.f[T]() is not decided: refuse it as today), as changed by ADR-grammar-2 D11: NK1233 only where a value argument’s type could have said the type (id[i64](3)); none where the brackets are the only source (json::read[Contact](bytes), parse[Config](text)). The callee’s path does not change the rule: a path to a generic function is the same form as a bare name.
No new code; NK1230 and NK1233 exist.

Locations

The checker’s test “a generic function declared in this file and no local of that name”: check_core_call.nika / check_core_pilot.nika (a104be7). It must also accept a path whose last segment resolves to a generic function, through the same resolution the checker uses for path calls today.
The emitter: emit_core_args.nika (the copy per type, or path::f::<T>(…)).
Parser: crates/nikaia/src/parser/mod.rs already parses Call{func: Index{base, index}}; check that base may be a path.
NK1230 today: check_core_expr.nika:431, check_buildtime.nika:223.

To build

Type arguments at a call whose callee is a path to a generic function (module of the same project, std), with the same filling, copying and NK1233 rule as a bare name. Tests in tests/compiler/tests/ (if a test cannot have a second module there, say how you tested under Tests:): type_arguments_on_a_path.nika + .stdout (no warning where the brackets alone say T), type_arguments_on_a_path_warned.nika + .stderr (a path to id[T](x: T), warning[NK1233]). Commit check, emit: type arguments at a call reached by a path (ADR-grammar-2 D11), Part of #1019.

Done when

The new tests pass through nikaia test --project tests/compiler; each failed once against the compiler without your change (say so under Tests:); the four tests of a104be7 still pass; lower-std fixpoint clean; cargo build --profile fast -p nikaia; the gate of .claude/agents/builder.md; pushed. Changelog: one line.

Stop and report if

An edit is needed outside crates/nikaia/src/parser/mod.rs, crates/nikaia-std/src/tools/check_*.nika, emit_*.nika, the resolution files they call, their lowered files and the new tests; json::read itself (that is #1019, not yours); a form beyond ADR-330 / ADR-grammar-2; 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.

Rules (CLAUDE.md; this block is pasted into every brief, also a fix-forward)

Read 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).
Before pushing: cargo fmt, cargo clippy --all-targets -- -D warnings, scripts/pre-push-check.sh, and the gate of .claude/agents/builder.md (#852).
No version lines, CHANGELOG.md, badges; no new NK code. New tests in Nikaia only; never the full suite. No foreground sleep, no polling; scripts in files.
A form Nikaia, 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).
A copied compiler binary must be named nikaia (tests that call the toolchain find it by that name).
Disk: NIKAIA_CACHE_LIMIT=2G; delete your own scratch files at the end; report GB freed.
Commit and push before you write the report; the report’s Pushed: line names the pushed sha.

Report (at most 15 lines, to exactly `/home/user/Nikaia/docs/briefs/b859d-path-type-arguments.md.report.md`)

Fields of docs/architect.md, Briefs and reports: Result: done|noop|partial|blocked (the bare word alone), Files, Commit, Body (optional), Fixes, Pushed, Tests, Gate (green|red), Deviation, Found, Needs, Changelog, Owner, Disk freed, Rs2nika (none). none where nothing, as the bare word. 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_01UVxJDvLe1uS47UcqA9y1U2

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Brief: type arguments at a call reached by a path (json::read[Contact](bytes), ADR-grammar-2 D11)

Problem (probe it with target/fast/nikaia check at your start)