feat(goose): add ZERO-294 Goose adapter

[spencercharest]

Summary

• Adds a Goose Open Plugins overlay at plugins/zero-goose with a versioned plugin.json and Goose SessionStart hook wiring.
• Adds scripts/build-goose.sh to assemble dist/zero-goose from the shared Zero skill and runner hook.
• Adds a standalone consumer guide at guides/goose.md and links it from the README Install Zero list.
• Bumps all versioned manifests to 1.4.0 via make minor.

Official references checked

• Goose repo: https://github.com/aaif-goose/goose
• Goose install docs: https://goose-docs.ai/docs/getting-started/installation/
• Goose Open Plugins docs: https://goose-docs.ai/docs/guides/context-engineering/plugins
• Goose hooks docs: https://goose-docs.ai/docs/guides/context-engineering/hooks
• Goose skills docs: https://goose-docs.ai/docs/guides/context-engineering/using-skills
• Goose extensions docs: https://goose-docs.ai/docs/getting-started/using-extensions

Verification

• ./scripts/build-goose.sh
• ./scripts/build-goose.sh --tar /tmp/zero-goose.tar.gz
• make version -> 1.4.0
• git diff --cached --check
• Confirmed guides/agent-install.md is not modified or staged.
• Docker install/load/hook smoke:

docker run --rm -v "$PWD":/repo -w /repo ubuntu:24.04 bash -lc '
set -euo pipefail
apt-get update >/dev/null
DEBIAN_FRONTEND=noninteractive apt-get install -y curl ca-certificates bash git jq bzip2 >/dev/null
curl -fsSL https://github.com/aaif-goose/goose/releases/download/stable/download_cli.sh | CONFIGURE=false bash >/dev/null
export PATH="$HOME/.local/bin:$HOME/.cargo/bin:$PATH"
goose --version
./scripts/build-goose.sh >/dev/null
mkdir -p "$HOME/.agents/plugins"
rm -rf "$HOME/.agents/plugins/zero"
cp -R dist/zero-goose "$HOME/.agents/plugins/zero"
GOOSE_PATH_ROOT="$HOME" goose skills list | grep -F "/root/.agents/plugins/zero/skills/zero"
PLUGIN_ROOT=/repo/dist/zero-goose /repo/dist/zero-goose/hooks/ensure-runner.sh >/tmp/hook.out 2>/tmp/hook.err
jq -e ".hookSpecificOutput.hookEventName == \"SessionStart\"" /tmp/hook.out >/dev/null
jq -r .hookSpecificOutput.additionalContext /tmp/hook.out | grep -F "Zero runner ready" >/dev/null
test -x "$HOME/.zero/runtime/bin/zero"
"$HOME/.zero/runtime/bin/zero" --help | head -n 1
'

Observed:

1.37.0
/root/.agents/plugins/zero/skills/zero
Usage: zero [options] [command]

E2E status

Draft because a full Goose-driven Zero capability call is still blocked in this environment:

• Host Zero auth check returns Authentication required from ~/.zero/runtime/bin/zero auth whoami --json.
• A model-backed Goose session was not configured in the Docker smoke test; goose session exits during onboarding/connectivity without a provider.

The adapter install, Goose skill discovery, and SessionStart runner provisioning path are verified.

Proposed guides/agent-install.md notes

Do not apply this text in this PR. This is the proposed runbook section to fold into guides/agent-install.md later.

### Goose

Use the Goose Open Plugins package when installing Zero for Goose.

Install/update from this repository:

```bash
git clone https://github.com/officialzeroxyz/zero-plugins.git
cd zero-plugins
./scripts/build-goose.sh
mkdir -p ~/.agents/plugins
rm -rf ~/.agents/plugins/zero
cp -R dist/zero-goose ~/.agents/plugins/zero
```

For updates, run `git pull`, rebuild, replace `~/.agents/plugins/zero`, then restart Goose.

Goose discovers plugin skills from `~/.agents/plugins/<plugin>/skills/` and project plugins from `<project>/.agents/plugins/<plugin>/`. The Zero skill is available as `zero` when copied directly into `~/.agents/plugins/zero`; Goose git-backed `goose plugin install` namespaces Open Plugin skills as `<plugin>:<skill>`.

Goose hooks live in `hooks/hooks.json` under the plugin directory. Zero wires only `SessionStart` for runner provisioning because Goose hook stdout is not an instruction-injection channel; Goose only treats blocking hook output specially. Do not document Zero auto-approval for Goose.

The Zero MCP connector is separate Goose config, not part of the Open Plugin directory:

```yaml
# ~/.config/goose/config.yaml
extensions:
  zero:
    enabled: true
    type: streamable_http
    name: zero
    uri: https://mcp.zero.xyz
    description: Zero capability search and account authorization
```

Equivalent Goose deeplink:

```text
goose://extension?type=streamable_http&url=https%3A%2F%2Fmcp.zero.xyz&id=zero&name=Zero&description=Zero%20capability%20search%20and%20account%20authorization
```

Claude-style plugin compatibility and simpler install option

Full Claude Code plugin package support: No. Goose uses its Open Plugins surface under .agents/plugins/ plus separate skill/MCP configuration. It can reuse Claude-compatible skill content, but it is not a documented Claude Code .claude-plugin installer.

What this means for users:

• Build steps should be maintainer/release-only. The consumer path should be a Goose plugin or recipe install from a published source, with Zero MCP configured through Goose's normal MCP surface.

• Preferred no-build shape:

  goose plugin install officialzeroxyz/zero-plugins/zero-goose
  goose plugin update zero

  Treat this as the productized target and verify exact Goose command syntax before moving out of draft.

• If the Goose-specific plugin is not worth maintaining, the simpler path is a skill + remote MCP recipe. That likely keeps most user value while dropping hook parity with Claude Code.

GitHub Releases / no-build install check

Result: No confirmed Gemini-style GitHub Release asset install path. Goose/Open Plugins can be distributed through Goose's own plugin/recipe surfaces, but I did not verify a native Goose installer that resolves GitHub Release assets the way Gemini does.

Best no-build consumer path should be a Goose-native plugin/recipe install from a published source, for example:

goose plugin install officialzeroxyz/zero-plugins/zero-goose

Treat that command as a target until verified against Goose's current installer syntax. A GitHub Release tarball can be a manual fallback containing ready-to-copy .agents/plugins/zero plus MCP/recipe files, but it should not be described as a native release install unless Goose docs/source confirm that behavior.

[spencercharest]

Folded into #63 as a matrix entry (goose in plugins/zero/agents.json) — standalone skills (~/.agents/skills, which goose reads natively) + MCP + a SessionStart-only hook-only Open Plugin fragment at ~/.agents/plugins/zero/hooks/hooks.json. No install block: goose plugin install is root-manifest-only (verified in source) and zero-plugins has no root manifest; #63 tracks the graduation path (dedicated installable source + --auto-update). The adapter-template work here stays available on this branch if we later ship per-host templates.