msd-core/.out-of-scope/omp-runtime-in-core.md

OMP (Oh My Pi) as a first-class runtime in gsd-core

gsd-core does not add omp (Oh My Pi) as a first-class runtime: no capabilities/omp/capability.json, no omp entry in the runtime registry, no omp alias canonicalization, and no installer runtime selection for it.

This is a scope decision, not a judgement about OMP or about the quality of the proposals that have asked for it.

Why this is out of scope

• GSD is not expanding its supported-runtime set. The long-term direction is to reduce the number of supported runtimes, not grow it, absent funded development. Each first-class runtime is a permanent maintenance obligation across the registry, installer, artifact conversion, agent discovery, model routing, dispatch isolation, golden install-parity fixtures, and localized capability matrices — carried indefinitely by the project, for a host it does not control.
• Host integration is the supported direction, and it is already available. The Embeddable Orchestration System (ADR-1239) exists precisely so a host can embed GSD and declare its own capabilities, instead of GSD resolving the host from an in-tree registry. An out-of-tree host plugin needs no runtime descriptor. GSD_AGENTS_DIR is a documented Priority-1 override honored for any runtime name (src/agent-install-check.cts, getAgentsDir), so a plugin can own its filesystem layout without core knowing the runtime exists.
• The ask as filed also carried a defect. #3037 proposed canonicalizing pi, oh-my-pi and pi-coding-agent to omp. OMP is a fork of pi (pi.dev), and gsd-core already ships a distinct pi runtime (capabilities/pi/capability.json, home ~/.pi/agent, tier 2). That alias list would relocate an existing shipped runtime's config home rather than add a new one. This is recorded so a future revision does not repeat it — it is a correction, not an additional ground for the decision.

What this does NOT cover

This entry denies in-tree, first-class runtime registration for OMP. It does not deny, and should never be cited against:

• Shipping an out-of-tree host plugin for OMP, or for any other host. This is welcome and supported. gsd-omp is already listed in docs/registries/eos.json and remains listed; registry inclusion is explicitly non-endorsement and is unaffected by this decision.
• Feature capabilities (role: "feature") published out-of-tree under ADR-1244. That is a different axis — what loop behavior you add, not which runtime you are.
• Fixing defects that happen to surface through a non-registered runtime, or improving the documented override contracts a host plugin depends on.
• Any other runtime's support tier. This entry is about OMP specifically and says nothing about existing runtimes, including pi.

Revisit if third-party role: "runtime" descriptors become loadable from outside the repo — ADR-857 D8 defers this to a purely additive external loader that has not been delivered — or if funded development changes the maintenance calculus that makes an additional first-class runtime unaffordable.

Prior requests

• #874 — "feat: Native OMP (Oh My Pi) Runtime Support" (closed not planned, 2026-06-08)
• #1948 — "Add Oh My Pi / OMP as a supported runtime" (closed as duplicate of #874)
• #1947 — implementation PR for #874 (closed unmerged)
• #3037 — "feat: complete first-class OMP runtime descriptor and registry integration" (closed not planned; the decision this entry records)

The first denial was never written down here, so the same request returned twice more. That is the reason this file exists.