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+# Intent: portable control-plane core
+Author: Yihan (operator). Status: draft.
+
+## Problem
+
+ystack's current control plane mixes its durable workflow with one preferred
+implementation. Core roles, prompts, model settings, review scripts, GitHub
+events, labels, secrets, and publishing commands name Claude, Codex, and GitHub
+directly. A different coding harness or Git forge cannot run the same governed
+loop without rewriting the product.
+
+That coupling also hides the true safety contract. Cross-vendor review is useful,
+but the requirement is separation of duties and independently verified evidence,
+not a particular pair of vendors.
+
+## Proposed outcome
+
+ystack has a small, vendor-neutral core that defines artifact and stage-result
+contracts, risk metadata, evidence references, and adapter capabilities. A
+selected profile supplies the producer, verifier, reviewer, forge, CI, execution,
+identity, and publisher adapters used by a stage. An adapter is a small bridge
+between the core and an external tool. The core's extension rules let later
+control, orchestration, deployment, and incident capabilities join without
+changing existing artifact or audit meaning; this initiative does not design or
+enforce those later controls.
+
+The current GitHub + GitHub Actions + Claude Code + Codex combination remains a
+working default while this core is introduced. Contract tests can swap fake
+harness adapters while holding the forge fixed, then swap fake forge adapters
+while holding the harness fixed. Each combination preserves the same artifact,
+policy, and audit contract. Contract validation rejects malformed or incompatible
+declarations. Later initiatives decide, prove, and enforce the capabilities a
+risk tier requires.
+
+## Affected users and systems
+
+The operator; future adopters; target repositories; the `work/` artifact chain;
+canonical stage/result schemas; profile resolution; capability declarations;
+fake adapters; contract tests; and the current setup that must keep working while
+later initiatives extract its real adapters.
+
+## Constraints
+
+- Git is the first canonical version-control and artifact protocol. GitHub is an
+  adapter, not a requirement.
+- Claude Code and Codex are preference adapters, not core requirements.
+- Core policies and artifacts cannot call vendor CLIs, APIs, events, secrets, or
+  model names directly.
+- Author, verifier, reviewer, and publisher capabilities remain separated. An
+  adapter cannot weaken no-self-approval, human merge, proof, or sandbox rules.
+- Canonical formats must be extensible across
+  `intent → spec → accepted plan → build → verify → independent review → human
+  merge → deploy/rollback → production feedback/new intent` without changing
+  earlier audit meaning. This initiative defines only the common artifact/result/
+  profile/capability foundation; later initiatives design and implement
+  orchestration, deployment, and monitoring.
+- The current setup must keep working unchanged. Real adapter extraction happens
+  in later initiatives; there is no one all-at-once rewrite.
+- ystack remains its own first target for dogfooding, but core contracts cannot
+  special-case the control-plane repo. Contract tests include an unrelated target
+  fixture, and a later external-target smoke is required before portability is proven.
+- Start with interfaces, fake adapters, and contract tests. Do not enable new
+  autonomous writes in this initiative.
+- Keep changes small, reversible, documented, and reconstructable from the repo.
+
+## Open questions
+
+- What is the smallest extensible result format for the complete
+  `intent → spec → accepted plan → build → verify → independent review → human
+  merge → deploy/rollback → production feedback/new intent` loop, without
+  implementing the later stages now?
+- What risk metadata and capability declarations must the core carry so later
+  policies can decide whether an adapter may support a risk tier?
+- Should canonical skills live under `.ystack/skills/`, an open Agent Skills
+  layout, or another neutral package with generated harness bridges?
+- What compatibility seams must the contracts expose so later adapter extraction
+  can preserve current behavior without putting vendor names in the core?
+- What fields must an evidence reference and fake-adapter contract-test result
+  carry so later eval initiatives can set real-adapter qualification rules without
+  changing audit meaning?