Net-new EoS/pi installable runtime — purely additive (no prior runtime==='pi'
branches). pi is a bun-runtime programmatic-CLI whose /gsd command is registered
by a native ExtensionAPI extension and dispatches through the embedded engine.
Stage 1 (install plumbing):
- capabilities/pi/capability.json: full hostIntegration descriptor (imperative /
slash-programmatic / active-model / native-extension / bun) + hostBehaviors
{nativePlugin, pluginOnlyInstall}.
- --pi flag + interactive-menu renumber (All 17->18); pi added to RUNTIME_FLAG_IDS,
RUNTIME_LABELS, RUNTIME_META, allRuntimes/runtimeMap, model-catalog defaults.
- Install mirrors OpenCode: pi installs the gsd.cjs extension + the shared engine
payload (gsd-core + scripts + config markers) + the shared hooks bundle (spawned
by the extension at lifecycle events, like OpenCode's plugin). pluginOnlyInstall
EXCLUDES declarative command/agent/skill markdown, which pi has no host-read
surface for (its /gsd is programmatic). _installNativePluginIfDeclared (extracted
from the opencode-family path) copies pi/gsd.cjs -> ~/.pi/agent/extensions/gsd.cjs
(global) / .pi/extensions/ (local). pi added to package.json files.
- Golden: new pi.json (320 files: extension + engine + 27-file hooks bundle, no
markdown); the 16 other fixtures + claude-local change only by the shared
model-catalog hash line.
Stage 2 (real dispatch + upgrades):
- Shared dispatchGsdCommand() (shell-command-projection): bounded, no-throw
subprocess-shim to gsd-tools.cjs (the only full-surface dispatch path; no
in-process full-hub factory exists). Fixes pi/gsd.cjs's createHub()-no-args bug
(every dispatch was UnknownCommand) AND the identical bug in mcp-server.cts's
gsd_invoke_command, which a vacuous unknown-family-only test had masked (now has
a real dispatch regression test).
- pi/gsd.cjs: /gsd handler now (args, ctx) - tokenizes (quote-aware, via the
shipped hooks/lib/git-cmd.js) + dispatches real family/subcommand (not hardcoded
query/help); gsd_invoke gets a TypeBox (JSON-schema-fallback) parameters schema +
consumes params; getArgumentCompletions; before_provider_request active-model
steering (fail-open on null resolution); functional session_start /
before_agent_start / session_before_compact hook bridges (spawn the shipped GSD
hook scripts).
- EXTENSION_EVENT_SURFACES.pi expanded from ['tool_call'] to the full 30-event
vocabulary.
Docs (host-integration matrix + how-to) + changeset (Added).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Proves the Programmatic-CLI reference binding for pi via the ExtensionAPI
imperative adapter (#1682 AC): createImperativeAdapter({runtime:'pi'}) classifies
as imperative + composes the registry; pi axes (imperative + bun) classify as
'programmatic-cli'; the reference pi host-plugin binds GSD via ExtensionAPI
(registerCommand /gsd + registerTool gsd_invoke + on tool_call).
Reference plugin (tests/fixtures/pi-host-plugin.cjs) is CJS + mock-friendly so
it is behaviorally testable without a live pi runtime. Full --pi installable-
runtime integration (descriptor + installer + golden parity 16→17) is a larger
follow-up — intentionally NOT added to the runtime registry here.
