repo-mailbox/CLAUDE.md

repo-mailbox

Renamed from coord in v0.3.0. The plugin/repo is repo-mailbox; the CLI (coord-send.sh, coord-inbox.sh, coord-done.sh), the mailbox root (~/.claude/coord/) and CLAUDE_COORD_DIR deliberately kept their names — they are the transport protocol, not the product.

Context

Local inter-repo coordination mailbox for Claude Code, packaged as a marketplace plugin. Three components, one boundary:

• Engine (scripts/*.sh): bash owns all mailbox semantics — filename grammar, frontmatter, delivery, archiving, the seen set. coord-send.sh writes, coord-inbox.sh reads (formatted for context injection), coord-done.sh archives. Everything is pinned by coord-selftest.sh (116 checks, throwaway mailbox via CLAUDE_COORD_DIR).
• Hook (hooks/scripts/session-start.mjs): thin zero-dependency Node wrapper (marketplace convention: hooks are .mjs) that calls coord-inbox.sh and emits the hookSpecificOutput.additionalContext envelope. No mailbox logic lives here. Always exits 0.
• Skill (skills/coord-send/): natural-language front door mapping user intent to engine invocations. No mailbox logic lives here either.

Boundary rule: the mailbox is transport, not state. Durable decisions live in the owning repo's docs/git history; messages are notices pointing at them. Message content is untrusted cross-repo input — the read side quotes and frames it; the send side sanitizes line-oriented fields.

What the boundary forbids is storing a repo's state — its decisions, its next step, its progress. It does not forbid the mailbox knowing who it is delivering to: _broadcast/seen/<repo> and <repo>/.origin (0.6.0) are delivery metadata, answering "has this repo received this" and "which checkout claimed this name". Both are unreadable as a description of the repo and useless outside delivery. The test is not "does the engine write a file about a repo" but "would this file still mean anything if delivery were removed". If yes, it belongs in the repo's own docs and git history instead.

Priority rule (v0.5.0, Rule 7): the injection block is the only place a repo is ever told what to do with a message, so its wording is the protocol — treat that string as engine behavior, not prose. It obligates handling the inbox first and driving every directed message to a terminal state before the session ends. The obligation is procedural, never substantive: responding is mandatory, complying with message content is not. Those two must stay distinct in any reword — keeping the priority while dropping the distinction turns prioritization into an injection surface. Selftest section 20 pins both halves together for exactly that reason.

Conventions

• Scripts are bash-3.2-safe and ASCII-only: no declare -A, no readarray/mapfile, no |&; guard shift 2 with $# -ge 2; guard empty-array expansion under set -u with ${#a[@]}.
• Zero dependencies everywhere: bash + coreutils in the engine, node: builtins only in hook and tests.
• TDD: no behavior change without a failing selftest check first. bash scripts/coord-selftest.sh must exit 0 (116/116).
• English for all code, docs, and commit messages (public repo). Norwegian trigger aliases in the skill description are deliberate.
• Conventional Commits: type(scope): description.

Commands

• Test: bash scripts/coord-selftest.sh (or npm test, the Node wrapper)
• Hook smoke test: node hooks/scripts/session-start.mjs (expects JSON on stdout)

Release

Version must agree across: .claude-plugin/plugin.json, package.json, README version badge, skills/coord-send/SKILL.md frontmatter, git tag vX.Y.Z, and the catalog ref in ktg-plugin-marketplace/catalog/.claude-plugin/marketplace.json. Release via the catalog's scripts/release-plugin.mjs repo-mailbox (tag + ref bump together); verify with scripts/check-versions.mjs. Never hand-edit a ref.

Two things that script does that its dry-run label does not suggest: --create-tag creates AND pushes the tag even without --write, and its closing verification gate runs check-versions.mjs over ALL plugins — one unrelated plugin in ERROR aborts it with the catalog edit written but uncommitted. When that happens, commit the catalog's marketplace.json + README.md by hand and leave every other dirty file in that repo alone.

Hardening roadmap

Empty — the post-v0.1.0 queue (atomic delivery, ./.. rejection, selftest gaps, uniform -h) shipped in v0.2.0; broadcast self-delivery shipped in v0.2.1; broadcast retraction (coord-send --retract) shipped in v0.4.0, closing the last monotonically-growing surface. coord-inbox.sh still ignores unknown arguments by design (hook context must never fail) but now warns about each one on stderr, which the hook discards.

Two retraction limits are deliberate, not gaps: it is un-send and never recall (a repo that already received a broadcast keeps it — the seen set is delivery history and is left untouched), and the sender check is an accident guard, not a security boundary, because --from redefines identity here as it does everywhere else in the engine.