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arc skill

Bundled ARC how-to booklets: list, show one by name, install into host .agents/.claude skills. Not a full gh-skill-style manager or AFS .skills inventory (yet).

arc skill is the CLI surface for bundled ARC how-to booklets (sometimes called L0): list them, print one, or copy them into host agent skill directories (.agents/skills, .claude/skills).

It is not (yet) a full agent-skill package manager like gh skill, and it does not inventory skills that live only under live AFS mounts (/{mount}/.skills). Those remain AFS paths (arc afs ls / read / exec). See the engineering post What arc skill is today for the three-layer map and open design gap (arc#1398).

Booklets are short, offline-safe. After a daemon is up, live AFS (arc afs ls / explain / read /.knowledge) is the source of truth for mounts and actions. Booklet text must not invent paths the live tree does not have.

Requires a CLI build that includes the skill command (from ARC 2.0.0-beta.30 / epic #3595 onward). Check with arc --help | grep skill or arc skill --help.

Usage

bash
arc skill
arc skill list
arc skill show <name>
arc skill show all
arc skill install <name>
arc skill install all

arc skill with no subcommand is the same as arc skill list.

Global options (all skill subcommands)

OptionMeaning
--jsonstructured JSON instead of default text
--view <default|llm|human|json>rendering style for command output (not --help); json is equivalent to --json
--instance <name> / -iwhich local ARC instance this runs against; omit for default (global, see Overview)
--home <dir>instance root (global). To pick which instance, use --instance
-h, --helphelp for this command or subcommand
-v, --versionCLI version

--yaml was removed (advertised on --help but never implemented); use --json or --view json.

list

Print the skill index: names, one-line descriptions, and how to obtain a booklet.

bash
arc skill list
# same:
arc skill
  • --source <bundled|host|afs|all> (default bundled): where to list from — bundled is the L0 booklets shipped with this CLI, host reads .agents/.claude skill dirs already on this machine, afs reads mounted providers' .skills roots via the live AFS (daemon if running, else ad-hoc), all is the union of the three

Example (text, abbreviated)

text
ARC skill index (L0 bootstrap — not a full manual)

Skills:
  daemon       Start, attach, and check the ARC daemon / service without breaking a live session.
  afs          Use AFS paths via `arc afs` (list/read/write/exec/explain) once a world is available.
  blocklet     Discover, scaffold, build, and inspect Arc blocklets via `arc blocklet` without reading the monorepo.
  mcp          Connect MCP clients (`arc mcp`) and explore the live AFS tool surface.

How to obtain:
  • Prefer per-name load: arc skill show <name>
  • Avoid full dump unless needed: arc skill show all
  • Install into host agent dirs (when available): arc skill install <name>
  • After a daemon is up, explore live AFS paths — this catalog is L0 bootstrap only

Commands:
  ...

Example (JSON)

bash
arc skill list --json
json
{
  "kind": "index",
  "skills": [
    {
      "name": "daemon",
      "description": "Start, attach, and check the ARC daemon / service without breaking a live session."
    },
    {
      "name": "afs",
      "description": "Use AFS paths via `arc afs` (list/read/write/exec/explain) once a world is available."
    },
    {
      "name": "blocklet",
      "description": "Discover, scaffold, build, and inspect Arc blocklets via `arc blocklet` without reading the monorepo."
    },
    {
      "name": "mcp",
      "description": "Connect MCP clients (`arc mcp`) and explore the live AFS tool surface."
    }
  ],
  "howTo": [
    "Prefer per-name load: arc skill show <name>",
    "Avoid full dump unless needed: arc skill show all",
    "Install into host agent dirs (when available): arc skill install <name>",
    "After a daemon is up, explore live AFS paths — this catalog is L0 bootstrap only"
  ]
}

The set of names is whatever this CLI build ships. Do not hardcode the list in agent memory across versions—run list again after an upgrade.

show

Show one booklet body, or every booklet at once.

bash
arc skill show <name>
arc skill show --name <name>
arc skill show all

Argument / optionRequiredMeaning
<name> or --nameyesskill id from the index, or all

Prefer one name. show all concatenates every booklet (on the order of ~10KB of text in current builds)—use it only when you intentionally want a full dump.

Example

bash
arc skill show daemon
text
---
name: daemon
description: Start, attach, and check the ARC daemon / service without breaking a live session.
---

# ARC skill: daemon
...

Errors

Unknown name fails closed with the known list:

bash
arc skill show not-a-skill
text
ERROR: unknown skill 'not-a-skill'. Known: daemon, afs, blocklet, mcp. Prefer: arc skill list

install

Copy a booklet (or every booklet) into host agent skill directories as SKILL.md. Offline; overwrites if the target already exists.

bash
arc skill install <name>
arc skill install --name <name>
arc skill install all

Argument / optionRequiredMeaning
<name> or --nameyesskill id from the index, or all

Paths written (under the current working directory):

  • .agents/skills/<name>/SKILL.md
  • .claude/skills/<name>/SKILL.md

Example

bash
mkdir -p /tmp/demo-agent && cd /tmp/demo-agent
arc skill install afs
text
Installed afs (2 file(s))
Policy: overwrite — same source as `arc skill show`; no second body tree

  /tmp/demo-agent/.agents/skills/afs/SKILL.md
  /tmp/demo-agent/.claude/skills/afs/SKILL.md

Body matches arc skill show afs (modulo a trailing newline). Re-run install after CLI upgrade to refresh installed skills.

Built-in booklets (current shipping set)

NameRole
daemonStart/attach/status for the ARC service without thrashing a live session
afsPath ops + discover protocol + UI/WM multi-terminal samples
blockletarc blocklet discover / scaffold / build without reading the monorepo
mcpBridge MCP clients into live AFS

After daemon + a running service, continue with live AFS:

bash
arc service status
# start only if needed — see arc skill show daemon
arc afs ls /
arc afs explain /
arc afs read /.knowledge

/.knowledge leads with an Agent bootstrap section on live daemons. Prefer that over memorizing mount tables.

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