conclave

One interface through which a coding agent, on any harness, spawns agents on any harness and exchanges messages with them. Any harness can be the parent and any harness the child; the verbs, the knobs and the output are the same whichever sits on either end.

Install

uv tool install agent-conclave
conclave install

The first line puts conclave on your PATH. The second puts in place what each harness on your machine needs — the skill, OpenCode's plugin, one Claude Code setting — and says where:

INSTALLED harness=claude skill=/home/you/.claude/skills/conclave crossSessionInbound=accept
INSTALLED harness=codex skill=/home/you/.agents/skills/conclave
INSTALLED harness=opencode skill=/home/you/.agents/skills/conclave plugin=/home/you/.config/opencode/plugins/conclave.js

Nothing else: no daemon, no server, no config file. Needs Linux or macOS, uv (which brings Python), and any of claude, codex and opencode on PATH.

Use

Tell your agent:

Use conclave: spawn a Codex reviewer for the diff of HEAD, then a Claude Code
worker to fix what it finds. Supervise both and report back.

The agent does the rest with the verbs below: it briefs children, waits for their results or has them pushed into its session, answers their questions and reports. A Codex parent runs with its sandbox off (--sandbox danger-full-access): the sandbox keeps its shell from writing conclave's state and its children from reaching the network.

Verbs

conclave spawn --harness <harness> [--cwd DIR] [--model M] [--effort E] [--name N] [message] [-- flags...]
conclave send <id|address> [message]
conclave wait <id> [--timeout SECONDS]
conclave list [--all]
conclave cancel <id>
conclave doctor
conclave install

A message is the positional argument or, when absent, stdin — a heredoc for anything longer than a line.

spawn starts a child: a new session on the harness, given the message as its first turn. It returns once the harness has named the session, which is also proof the harness started — or, when the turn is already over by then, with its result, as wait would print it:

SPAWNED id=reviewer-8f3a harness=claude session=01a84a47-…

send gives a child its next message; its session is resumed for one more turn. A child's turns run one at a time, in the order they were sent, so a message to a busy child waits its turn:

SENT id=reviewer-8f3a turn=2

Sent to an address instead — claude:<session-id>, codex:<thread-id> or opencode:<session-id>@<server-url> — the message goes into that live session's inbox and arrives the way its harness takes a message from outside: Claude Code reads it between tool calls, Codex once its running turn ends, OpenCode at its next step; when the session is idle, it starts a turn. CONCLAVE_PARENT is such an address, or the parent's own id when the parent is itself a child, so conclave send "$CONCLAVE_PARENT" … reaches the parent either way:

SENT id=claude:01a84a47-…

wait blocks until the child's next result and prints it — oldest first, each result once, however many times you ask:

DONE id=reviewer-8f3a turn=2
<the child's final message>

FAILED (exit 1) carries the error, whole: the harness's own, or what kept it from starting. CANCELLED carries nothing. With --timeout, TIMEOUT id=… after=30s busy or … idle says whether a turn is still running; the same command again picks up where it left off. Nothing is lost when a wait is cut short: results stay until delivered.

list prints one line per child of this session — --all for everyone's, each line then ending in parent=:

id=reviewer-8f3a harness=claude status=busy turn=2 unread=0 session=01a84a47-… cwd=/work/repo

cancel stops whatever is in flight for a child and prints how many turns it stopped. That line is those turns' result: wait does not print them again. The session stays resumable: the next send starts a new turn.

CANCELLED id=reviewer-8f3a turns=1

doctor pushes a probe to this session the way results are pushed, and says where it went:

PROBED address=claude:01a84a47-…

The probe arrives as a message from outside — proof that pushed results will. In a child it prints CHILD id=… and probes nothing: a child's results arrive as its next turn.

install is the second line of the install above; what it puts in place, and where, is under "Where things are". The links point into the installed package, so upgrading conclave upgrades them; run it again if a harness arrives later.

Results

A result reaches its parent once, by the first of these that applies:

• wait — whoever is waiting on the child gets it.
• A push — with nobody waiting, the result is delivered as a message into the parent's session: [conclave] DONE id=reviewer-8f3a turn=2 and the text below it, exactly what wait would have printed.
• The state directory — when the push cannot reach the parent, the result stays for wait, and list counts it as unread.

A push lands in the parent's own inbox: Claude Code's session socket, Codex's codex queue, OpenCode's server. Codex needs nothing for it. OpenCode needs its plugin, which install put in place: it tells the session's shell which session it is and where its server listens — how conclave learns who it is working for. Claude Code, when the session bypasses permission prompts, holds messages from outside unless crossSessionInbound is accept: install seeded it, a project's or an organization's settings can tighten it, and conclave doctor tells.

Knobs

--model and --effort go to the harness verbatim, on every turn; the harness validates them and its errors come back as FAILED. --name gives the child a short name; the id is <name>-<hex>. --cwd is the child's working directory. Anything after -- rides the harness's launch line, verbatim, every turn.

Children

Children never prompt: each harness runs in its skip-permissions mode, with no sandbox. A child asks by ending its turn with the question; the parent answers with send. A child knows who it is and who spawned it through CONCLAVE_SELF (its id) and CONCLAVE_PARENT (the parent's address). A Claude Code child accepts messages sent to its address, mid-turn: it is launched with that setting on its own launch line.

A brief that works is self-contained — the child shares none of your context — states one job, and says how to finish: end the turn with the report you need. The final message is the result wait prints.

Where things are

~/.local/state/conclave/children/<id>/
    meta.json          what was spawned; never changes
    waiter             locked while someone waits, so results wait for them
    turns/<n>/
        message        what the child was told, verbatim
        stream         the harness's own output, one JSON line per event
        stderr         the harness's stderr, and the runner's
        runner, pid    process ids of the turn's owner — the caller, then
                       the runner — and of the harness
        session        the session id, as soon as the harness names it
        exit           the harness's exit code, when the runner saw it
        cancel         present once a cancel was asked for
        result         how the turn ended: status and text; written once
        delivered      present once the result was handed on

XDG_STATE_HOME moves the root. A session sees its own children: list is scoped by the parent's address, which comes from the session variables of the harness running the shell — CLAUDE_CODE_SESSION_ID, CODEX_THREAD_ID, or the plugin's OPENCODE_SESSION_ID and OPENCODE_SERVER_URL; the nearest harness when they nest — or from CONCLAVE_SELF when the parent is itself a child.

What install puts in place — three symlinks into the installed package, and one key:

~/.agents/skills/conclave                 the skill, where Codex and OpenCode look
~/.claude/skills/conclave                 the skill, where Claude Code looks
~/.config/opencode/plugins/conclave.js    the plugin, where OpenCode loads plugins
~/.claude/settings.json                   crossSessionInbound: accept, where nothing set it

The key is the setting Claude Code documents for unattended workers, and it applies to every Claude Code session you run; why a session needs it is under "Results". install seeds it only where nothing sets it, never overrides a value you chose, and writes nothing else into any settings file. CLAUDE_CONFIG_DIR and OPENCODE_CONFIG_DIR move the harness directories here as they do for the harness. To remove conclave, delete the three links, drop the key, and run uv tool uninstall agent-conclave.