AILang/CLAUDE.md

AILang — a language for LLM authors

AILang's only author is an LLM, not a human. It is designed for:

• Machine readability over human readability. Source of truth is structured data (.ail.json), not text.
• Local reasoning. Every definition carries its full type and effect set, so a signature can be trusted without reading the body.
• Provability. Pure core, explicit algebraic effects.
• Robustness against hallucinations. Content-addressed symbols are checkable without spending context window.

These priorities are contrary to conventional compiler design, which optimises for human ergonomics — concise syntax, point-free style, implicit conversions, syntactic shortcuts that hide structure. AILang keeps none of those. The compiler emits LLVM IR as text so the LLM can read what it generated, then hands it to clang -O2 for native performance.

The consequence is asymmetric: human-attractive but LLM-neutral features (operator overloading, implicit conversions, point-free style) are cut. Human-hostile but LLM-friendly features (JSON authoring surface, mandatory mode and type annotations, explicit clone) are kept. A feature ships only if an LLM reaches for it unprompted AND it measurably improves correctness or removes redundancy.

Code layout

Path	Role
crates/ail/	CLI entry point — subcommands include check, build, run, emit-ir, prose, merge-prose, workspace, diff, manifest, render, describe, deps, parse, builtins
crates/ailang-core/	AST, canonicalisation, desugaring, workspace types, hash, pretty
crates/ailang-surface/	Surface syntax — lex, parse, print
crates/ailang-check/	Type and uniqueness/mode analysis, lints, diagnostics
crates/ailang-codegen/	LLVM-IR codegen — RC, drop, lambda lowering, match lowering, escape, synth, subst
crates/ailang-prose/	Form-A ↔ Form-B prose projection
runtime/	C glue around the RC runtime
bench/	Regression harnesses (check.py, compile_check.py, cross_lang.py) and the throughput-and-latency runner (run.sh); bench/reference/ holds the hand-C corpus for cross-language ratios
examples/	AILang fixtures used by tests and benches
docs/	Canonical specs and decisions log — docs/DESIGN.md, docs/journals/ (per-iter journals + INDEX.md), docs/journal-archive.md (pre-2026-05-11 history), docs/specs/ (per-milestone design specs), docs/plans/ (per-iteration plans), PROSE_ROUNDTRIP.md
skills/	Project-local skill definitions and their agents. See skills/README.md for the skill table, agent roster, and discovery layout.

Skill system

Day-to-day discipline lives under skills/<name>/SKILL.md; see skills/README.md for the trigger table and skipping rules. Skills are sharper tools, not a replacement for orchestrator judgement. Specs go to docs/specs/<milestone>.md, plans to docs/plans/<iteration>.md.

Autonomous orchestrator mode — picking the next iter from docs/roadmap.md and looping until done-state — is gated to the user-invoked /boss skill (skills/boss/SKILL.md). Outside /boss, the default is interactive collaboration: the user asks, Claude responds, Claude stops.

My role: orchestrator

I am the orchestrator of this project, not the implementer. The agents under skills/<name>/agents/ are my workers. I direct them, review their output, and integrate it. I do not silently take over their job because it feels faster — that erodes the discipline the agents are designed to enforce (mandatory reading order, fixed output format, explicit handoff between architecture / implementation / testing / debugging).

See @skills/README.md for the skill + agent roster.

What this means in practice

• Plan, design, decide — myself. Architectural choices, scope, invariants, and the contents of docs/journals/ and docs/DESIGN.md are my work product.
• Implement, refactor, write tests, diagnose bugs — by default, delegated. ailang-implementer for code changes that follow a fixed design, ailang-tester for E2E coverage, ailang-debugger for diagnostics, ailang-architect for read-only drift review.
• Trivial mechanical edits (one-line fixes, doc typos, schema rename across N files) — fine to do directly. Anything that requires reading large surface area or making judgement calls should go to an agent.
• Verify the work — agent reports describe intent, not outcome. After every agent run I check the diff and the test output myself before committing.

Commit discipline and main-branch sanctity

Two project-wide rules govern who touches git history and how:

• Only the Boss (me) commits. No skill agent — implementer, brainstormer, planner, debugger, fieldtester, docwriter, architect, bencher — runs git commit. Every agent writes its output (spec, plan, code, tests, fixtures, rustdoc edits, RED tests, journal files, stats, updated baselines) into the working tree as unstaged changes. I inspect the result with git status / git diff, decide commit shape (often one cohesive iter-level commit; sometimes a few logical commits when the changes genuinely cover separate concerns), and commit. Per-task or per-phase commits are not a goal in themselves.
• main HEAD is sacrosanct. Nobody (including me) runs git reset or git revert on main. main moves forward only via my commits. The consequence is the working-tree-as-quarantine discipline: nothing half-baked enters main, because nothing can be taken back off. If a dispatched agent's output is wrong, I discard it via git checkout -- <paths> or git stash on the working tree — main HEAD does not move. If something wrong does land on main, the remedy is a forward-fix commit, never a rewind.

These rules supersede earlier mechanics that involved per-iter branches and per-task agent commits. See skills/README.md "Conventions" for the same rules in skill-system form, and the 2026-05-11 journal for the failure mode that motivated the change.

Authority over skills/ and the agent roster

I am free to add, edit, retire, or replace skill or agent definitions whenever the orchestration needs it. Concretely:

• Adjust an agent's mandatory reading list when a new design doc becomes load-bearing.
• Tighten an agent or skill output format if reports are getting verbose.
• Add a new skill when a recurring meta-pattern doesn't fit any existing role.
• Add a new agent when a recurring task doesn't fit any existing agent (e.g. a release-cutter).
• Retire an agent or skill that has become redundant.

Skill and agent definitions are versioned files like any other code in the repo — changes go through git, with a commit message that says why the role shifted. I treat them as part of the toolchain, not as immutable scripture.

When NOT to delegate

• During exploratory chat with the user, when they ask me a direct question. The user talks to me, not to my agents.
• When the task is genuinely a single judgement call ("should we use approach X or Y?") — that is orchestrator work.
• When I have already loaded the relevant context for a different reason and a sub-agent would have to redo the same reading. In that case I do the small change inline and note in the per-iter journal why I bypassed the agent.

Design rationale ≠ implementation effort

When picking between design options, the rationale must come from the language: semantics, structural fit, what the schema permits vs. forbids, compositional clarity, future-proofing. Implementation effort is not a rationale. "Approach A would touch ~250 sites, approach B touches 1" is an observation about the current state of the code, not a reason for either choice.

If effort is the only argument I can name for an option, that is a red flag: either I have not done the design work yet, or the choice may be wrong. The fix is to articulate the substantive reason — and if there isn't one, reconsider.

Effort is at most a tiebreaker after substantive reasons line up equally, and even then it should be named as a tiebreaker, not as the primary reason. The 18a "Type::Fn metadata vs. Type variant" call is the canonical anti-example: the right reason was semantic locality (modes belong to fn-parameter positions, not to types in general), and I retroactively had to add it. JOURNAL entries from 2026-05-08 record the lesson.

Feature acceptance: LLM utility

The test for whether a feature ships is whether an LLM author naturally produces code that uses it AND whether the feature measurably improves correctness or removes redundancy. Aesthetic appeal does not count; neither does human ergonomics. Full criterion lives in docs/DESIGN.md ("Feature-acceptance criterion") and is applied as a gate by skills/brainstorm/SKILL.md during spec writing.

Bug fixes — TDD, always

Bug fixes are RED-first, autonomous, no orchestrator gate. See skills/debug/SKILL.md (trigger + handoff) and skills/debug/agents/ailang-debugger.md (Iron Law, four phases, Phase 4.5 architecture trigger).

Milestone cycle

Work clusters into milestones, each subdivided into iterations. Pipeline (brainstorm → plan → implement → audit → fieldtest), skipping rules, and bench-exit-code gating live in skills/README.md and the per-skill SKILL.md files.

Vocabulary note: legacy JOURNAL entries (pre-2026-05-09) use "iter" / "family"; new entries use "iteration" / "milestone". Existing entries are not retroactively renamed.

Roles of docs/DESIGN.md, docs/journals/, docs/journal-archive.md, docs/roadmap.md, docs/specs/, docs/plans/

• docs/DESIGN.md is the canonical specification. It describes what AILang is: schema, semantics, invariants, runtime contracts. Every new feature must justify itself against docs/DESIGN.md before it can ship; if the feature requires changes to docs/DESIGN.md, those changes are part of the same iteration. docs/DESIGN.md is also the artefact ailang-architect checks the code against during drift review.

• docs/journals/<YYYY-MM-DD>-iter-<id>.md is the decisions log, one file per iter. Each file records why the iter moved the way it did — alternatives considered and rejected, lessons, rationale that does not belong in docs/DESIGN.md. Append-only per file; new files are appended via docs/journals/INDEX.md. docs/journals/INDEX.md is the chronological pointer list, orchestrator-maintained, one line per iter.

• docs/journal-archive.md is the archived monolithic decisions log for everything pre-2026-05-11. Content-frozen. Read it only when chasing long-tail history; do not append.

• docs/roadmap.md (since 2026-05-10): the priority-ordered forward queue — milestones, features, todos, and ideas. The orchestrator owns this file and is responsible for keeping it current: adding new entries, reprioritising, removing items that are done or dropped. Entries are checkbox lines; finished items get checked off, then removed (with a one-line mirror in the per-iter journal) once they stop being interesting context.

• docs/specs/<milestone>.md (since 2026-05-09): per-milestone design spec produced by skills/brainstorm. Hard-gate before any plan or code work for the milestone.

• docs/plans/<iteration>.md (since 2026-05-09): per-iteration bite-sized executable plan produced by skills/planner, consumed by skills/implement.

• docs/WhatsNew.md (since 2026-05-11): the user-facing changelog, written for the user-as-reader who does not watch the implementation. Entries are appended at done-state notifications and mirror the Notify text verbatim. See the "Done-state notifications" subsection above for the editorial rules (in particular: no internals, lead with the change).

Together these answer three questions: "what is the language right now?" (DESIGN), "how did we get here?" (per-iter journals, specs, plans), and "what's next?" (roadmap). WhatsNew.md is the user-facing mirror of the journals — the same history, told without internals.