repo-mailbox/skills/coord-send/SKILL.md
Kjell Tore Guttormsen 1d62b073f8 fix(engine)!: identity is derived, never invented
Four defects that all reduce to the same thing: the engine trusted a name it
had no business trusting.

_broadcast is now a reserved namespace, not a repo. coord-send guarded
retraction with a sender check, but that guard only covered the door it was
nailed to: `coord-done --repo _broadcast <file>` walked in the side entrance
and archived a broadcast out of the queue - a full unauthenticated retract of
an announcement for every repo that had not read it yet. The rule reserves the
whole `_` prefix rather than one literal, so a later `_seen` or `_config`
cannot reopen the hole, and it is enforced in every CLI: a rule held in three
of four places is not a rule.

The pwd fallback is gone. It existed so the CLI would work anywhere, but
"anywhere" includes every global surface: a session in ~/repos is not a repo,
and basename(pwd) silently handed it the identity "repos". That is not
hypothetical - mail was delivered under exactly that name. git toplevel or an
explicit --from/--repo are now the only two sources. The write paths refuse
and say so; the read path declines silently, because the hook runs it at every
session start and must never fail a session.

Two checkouts with the same directory name still share one mailbox - re-keying
identity would break every existing mailbox and the readable `--to <repo>`
addressing. Instead the first git-derived read records the claiming path in
<repo>/.origin, and a read from elsewhere is warned about in the injection. A
warning, not a refusal: the same repo moved or re-cloned is the ordinary case.
The warning goes in the injection because the hook discards stderr, and a
warning nobody can see is not a warning. The collision is live in this tree:
claude-code-100x is nested inside a repo of the same name.

Broadcast delivery is recorded only after the injection is written. Marking
inside the read loop left a window where the seen set said "delivered" while
the operator saw nothing, and the hook runs under `timeout: 10`, so the window
was reachable. A lost broadcast is unrecoverable by design - the seen set is
delivery history and retraction deliberately leaves it alone - so the failure
mode has to be redelivery, never loss.

The hook stops resolving identity altogether. It was the fourth copy of the
rule and the only one that runs in production, so passing --repo bypassed the
engine's guards exactly where they mattered and suppressed the collision check
along with them. It is now the pure wrapper the boundary rule always claimed
it was, pinned by two behavioral tests rather than by reading the source.

Selftest 93 -> 116; three node tests cover the hook.

BREAKING CHANGE: coord-send and coord-done exit 2 outside a git repo instead
of naming themselves after the working directory. Pass --from/--repo to choose
an identity explicitly. Repo names beginning with _ are refused everywhere.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01U6EixQo6hpoRCVtiAXdnFs
2026-07-25 20:34:43 +02:00

8.5 KiB

name description version
coord-send Send an inter-repo coordination message through the local coord mailbox — a natural-language front door over the `coord-send` script. Use this whenever the user wants to notify, tell, message, ping, or coordinate with another repository (or all repositories) about work happening in the current repo: "send info to all repos", "tell repo-x the bug is fixed", "let repo Y and Z know", "broadcast that the spec changed", "reply to that coord message", or a deferred/conditional notice like "when the build is green, notify repo X". Also triggers on Norwegian phrasings: "send info til alle repo", "varsle repo X", "gi beskjed til Y og Z", "kringkast at …", "svar på coord-meldingen", "når Z er ferdig, varsle X". Trigger even when the user names a repo plus something to convey without saying "coord" explicitly — routing a message to another repo IS this skill. Also covers retiring a broadcast that has become wrong or obsolete: "retract that broadcast", "that announcement is outdated, pull it", "trekk tilbake kringkastingen", "den broadcasten er utdatert". 0.5.0

coord-send — natural-language front door for inter-repo messages

This skill turns a plain request ("tell repo X that Y happened") into the right coord-send invocation. The script is the engine; this skill is only the mapping from intent to arguments. It never edits mailbox files by hand — always go through the script, because the script owns the filename grammar, frontmatter, and delivery guarantees.

Boundary — why messages are thin

The mailbox is transport, not state. A coord message is a notice, not the source of truth. The durable record of any decision lives in the owning repo's state files / docs and its git history. So when you compose a body, write a self-contained heads-up and point at where the real record lives (a commit hash, a doc path) — don't try to make the message itself the canonical artifact. Coordination content is also private: it never belongs on a public surface.

The engine

Resolve the script path portably — this one expression is correct both when the skill runs bundled inside the plugin and when the scripts are installed as personal scripts under ~/.claude/scripts/:

CSEND="${CLAUDE_PLUGIN_ROOT:-$HOME/.claude}/scripts/coord-send.sh"

Interface (body comes from a quoted heredoc so nothing in it is shell-expanded):

# to one repo
"$CSEND" --to <repo> --subject "<subject>" <<'BODY'
<message body>
BODY

# to every repo (accumulates; first-time newcomers see it too)
"$CSEND" --broadcast --subject "<subject>" <<'BODY'
<message body>
BODY

# reply to a message this repo received (routes to the original sender and
# marks the original handled; target + "Re: …" subject are inferred)
"$CSEND" --reply-to <message-filename> <<'BODY'
<message body>
BODY

# retire one of THIS repo's own broadcasts (no subject, no body)
"$CSEND" --retract <broadcast-filename>

Sender identity (--from) defaults to the basename of the current git toplevel, so you almost never set it. Outside a git repo there is no default — the send refuses with exit 2 rather than naming itself after the working directory, so on a global surface (~/repos, $HOME) pass --from <repo> and make the identity a choice. Exit 0 = delivered; exit 2 = usage/IO error (read stderr and fix the arguments rather than retrying blindly).

Choosing the target

  • One named repo--to <repo>. The repo name is its directory basename; use the name the user gave. No registration exists — sending to a new name just creates that repo's inbox, so a typo silently creates a dead mailbox. If unsure a name is real, check ~/repos/ or existing ~/.claude/coord/<repo>/ before sending.

  • Several named repos ("X and Y") → loop --to once per repo with the same subject and body. There is no multi-target flag; the loop is the mechanism:

    for repo in repo-x repo-y; do
      "$CSEND" --to "$repo" --subject "<subject>" <<'BODY'
    <body>
    BODY
    done
    
  • All repos--broadcast. Prefer this only when the notice genuinely concerns everyone, because broadcasts accumulate and every future first-time repo sees the standing backlog. For a bounded, known set, loop --to instead so unrelated future repos don't inherit it. A broadcast that later turns out wrong can be retired with --retract (see below), but only for repos that have not received it yet.

  • A reply to something received--reply-to <filename>. Use the filename from the injected inbox/archive; it resolves the sender and closes the original in one step.

Retracting a broadcast

When a broadcast has become wrong or obsolete, retire it — don't send a correction and leave the original standing, because every future first-time repo would receive both. --retract <broadcast-filename> archives it out of the delivery queue.

Three things to be honest about when you report it:

  • It is un-send, not recall. Repos that already received the broadcast keep it. Retraction only stops delivery to repos that haven't seen it yet. If the old news actively misleads someone who already got it, a correcting broadcast is still needed — retraction alone does not reach them.
  • Only the sender may retract. The from: field must match this repo's identity. If the announcing repo has since been renamed, its old identity no longer resolves, so pass --from <old-sender> explicitly (read the sender off the file). Say that you did.
  • Nothing is deleted. The message moves to _broadcast/archive/. Never remove a mailbox file by hand — the script owns the filename grammar and delivery guarantees.

Find the filename in ~/.claude/coord/_broadcast/inbox/ (or from the injected --- broadcast: <filename> --- line) rather than guessing it.

Composing the message

Derive a short, specific --subject from the intent if the user didn't give one ("ingest bug fixed", not "update"). In the body, state what happened, what the recipient should know or do, and a pointer to the durable record (commit hash, doc path). Keep it to the point — this is a notice, not a report. Match the repo's language convention for message content; keep it sober and factual.

Deferred and conditional sends

"When Z is done, notify X" means: do not send now. Hold the intent — the target, subject, and body — and continue the work. The moment condition Z is satisfied in this session, fire the send. This works because you carry the intent across turns within a session.

Be honest about the limit: a skill cannot persist intent across sessions. If the session is ending and the condition still hasn't been met, surface the pending message to the user so it isn't silently lost — don't imply it will fire later on its own.

After sending

Report what actually happened: the target(s), the subject, and the delivered filename(s) from the script's stdout. If a send failed (exit 2), say so with the stderr reason rather than claiming success. Delivery reaches the recipient at their next session start (the receive side is a hook), so tell the user it's queued, not that the other repo has seen it.

Examples

Example 1 — single repo, composed body Input: "tell repo-x the ingest bug is fixed, it was commit abc1234" Action: --to repo-x --subject "ingest bug fixed", body naming the fix and pointing at commit abc1234 and the owning doc.

Example 2 — broadcast Input: "let all the repos know the shared spec grew a new validation rule" Action: --broadcast --subject "spec: new validation rule", body summarizing the change and pointing at the spec's owning repo.

Example 3 — bounded multi-target Input: "gi beskjed til repo-x og repo-y om at gaten er re-pinnet" Action: loop --to repo-x then --to repo-y, same subject "shared gate re-pinned".

Example 4 — deferred Input: "når testene er grønne, varsle repo-y" Action: keep working; once the test run passes this session, send --to repo-y with the green result. If the session ends first, surface the pending notice to the user.

Example 5 — reply Input: "svar på coord-meldingen fra repo-x at vi tar det" Action: --reply-to <that-message-filename>, body acknowledging and stating the plan.

Example 6 — retract Input: "den gamle kringkastingen om plugin-navnet er utdatert, trekk den" Action: locate the file in _broadcast/inbox/, then --retract <that-filename> (adding --from <old-sender> if this repo has been renamed since). Report that repos which already received it are unaffected.