Lightweight proof-workspace manager for Agda — the language-agnostic engine half of arghda. Extracted from hyperpolymath/echo-types to its own repository on 2026-05-30 (see echo-types#159 for the move record).

arghda-core organises, lints, and reports on an Agda proof workspace; it never proves anything itself — Agda does. It manages a four-state triage workspace (inbox → working → proven → rejected) as file moves, runs a lint pack targeting the silent-failure class (cases where Agda appears to succeed but the file is not actually in the verified suite), builds a first-class import-graph DAG, and emits a JSON + event-stream contract a visual layer consumes.

Status

v0.1 is feature-complete against docs/arghda-spec.adoc: all seven v0 Agda lint rules, the four-state workspace state machine, the import-graph dag, the check command (Agda typecheck + lint verdict), content-hash invalidation of proven, and .arghda/config.toml operator configuration. The live status of record is STATE.a2ml.

Lint rules

Hard-block (forbids the working → proven transition):

• missing-safe-pragma — file lacks {-# OPTIONS --safe --without-K #-}.

• orphan-module — .agda file unreachable from any CI root (roots are auto-discovered as All.agda/Smoke.agda, or passed via --entry; reachability is the union, so a module verified from any root is not an orphan).

• unjustified-postulate — postulate without an adjacent -- JUSTIFY: comment.

Warn (surfaced, non-blocking):

• escape-hatch — termination overrides (TERMINATING, NON_TERMINATING, NO_TERMINATION_CHECK) and trust primitives (believe_me/primTrustMe).

• tab-mix — a tab in leading whitespace.

• unpinned-headline — a top-level theorem whose name matches the headline pattern is not pinned in any Smoke.agda via a using ( … ) clause (the estate “every headline pinned in Smoke” discipline). The pattern is operator-configurable; its default ^[a-z][A-Za-z0-9-]*$ is deliberately broad, so operators narrow it to their own convention. Self-skips when no Smoke.agda is in scope.

• unused-import — re-emits the findings of the external agda-unused tool. Opt-in behind scan --unused; invoked per file in local mode with LC_ALL=C.UTF-8; skipped with a note if the binary is not on PATH.

Commands

The CLI is arghda.

Command	What it does
init	Create the four-state workspace layout at a path.
scan	Lint every .agda file under a path. --unused adds the agda-unused pass; --config/--headline-pattern tune configuration.
check	Run Agda on one file and lint it; combined verdict (degrades when agda is absent).
dag	Emit the dependency-DAG JSON — nodes (lint status + declared headlines), import edges, and a blocked list.
claim / promote / reject / requeue / invalidate	State-machine transitions; each is a file move logged to .arghda/events.jsonl.
events	Replay the workspace event log.
stale	List proven files whose content changed since promotion; --invalidate returns them to inbox.
watch	Watch inbox/ and working/ and print events.

Configuration

scan and dag read .arghda/config.toml (from <PATH>/.arghda/config.toml, or an explicit --config <file>). Precedence is built-in default < config.toml < CLI flag.

[lint]
headline_pattern = "^[a-z][A-Za-z0-9-]*$"

Build

just check    # fmt-check + clippy (-D warnings) + build + test — the CI gate
cargo build
cargo test

agda and agda-unused are optional: the check and scan --unused paths degrade gracefully (with a note) when the binary is absent, so the rest of the engine still works in an Agda-less environment.

Smoke against an Agda workspace

cargo run -- scan path/to/your/agda/sources

Dogfooded against the echo-types corpus (193 modules): dag emits the 903-edge import graph; multi-root discovery (All.agda, Smoke.agda, Ordinal/Buchholz/Smoke.agda, characteristic/All.agda, examples/All.agda) narrows orphan reports from 38 to the 17 genuine orphans.

Ecosystem

Part of the hyperpolymath ecosystem. arghda splits into arghda-core (this engine) and the planned arghda-studio / arghda-panll visual layers, which consume the dag JSON + events.jsonl contract. The motivating workspace was the echo-types proof pipeline, but arghda-core has no echo-types-specific code.

Adjacent projects:

• echo-types — the Agda library that motivated arghda’s design (not a build dependency).

• absolute-zero — a sister Agda library under the same --safe --without-K discipline.

Machine-readable

Per the Rhodium Standard, structured project metadata lives under .machine_readable/6a2/ — STATE, META, ECOSYSTEM, AGENTIC, NEUROSYM, PLAYBOOK in A2ML — with 0-AI-MANIFEST.a2ml as the AI entry point and EXPLAINME.adoc as the orientation pointer.

Licence

Code, configuration and scripts are MPL-2.0 (see LICENSE); prose documentation is CC-BY-SA-4.0, per the hyperpolymath licence policy (Rule 1). This split is a formal invariant: every tracked file carries the appropriate SPDX header, checked by scripts/check-spdx.sh in just check and in CI. Third-party, generated, and test-data files are explicitly excluded (licensing-policy.toml) and are never relicensed — vendoring third-party source in-tree fails the check until it is listed as excluded with its original SPDX preserved.