Context and Problem Statement

Every tracker operation in this kit was a direct gh call — 111 lines across 18 scripts and 189 across 39 prose files — and skills/_shared/preconditions.md could answer only “GitHub, or stop”. #503 asked for GitLab and Azure DevOps support, and there was nowhere to put it: no place a second host’s dialect could live, and no way to state a partial answer such as “create-issue works on GitLab, merge-pr does not yet”. The refusal a non-GitHub repository met was also generic — it named the tracker but not which skill was blocked or what would unblock it.

Considered Options

• Keep gh everywhere and refuse anything else at preconditions. The status quo: cheapest, and it keeps GitHub byte-identical, but #503 is unimplementable under it and the refusal stays generic.
• An adapter per skill — each skill learns the hosts it supports, calling each host’s CLI directly. No new indirection on the GitHub path, but the host dialect spreads across 18 scripts again, once per skill, and “which hosts work?” has as many answers as there are skills.
• One contract with a per-host backend and a registered capability verdict. A verb has one name and one normalised stdout; a backend implements verbs for one host; a registered decision answers whether a given skill may run against a given host.

Decision Outcome

The kit takes the third option: scripts/tracker.sh routes a named verb to scripts/tracker/<tracker>.sh, the verb table lives once in scripts/tracker/contract.json, and the registered decision tracker.capable — asked at Step 1 of every lifecycle skill — answers capable, missing or unsupported from the state report the dispatcher produces. GitHub is the reference backend and is deliberately never reduced to a lowest common denominator: a verb prints what GitHub can actually say, and a host that cannot say it answers NOT_IMPLEMENTED rather than every host answering less. Because GitHub answers capable for every skill — an unmigrated skill’s direct gh calls are correct there — this change refuses nothing that worked before it, and a relation a host simply lacks (a sub-issue edge, a blocked-by link) degrades through the established fallback rule rather than failing the verb.

Consequences

The GitHub path gains one indirection for each migrated call site, which buys a single home for the host dialect and a refusal that can finally name both the skill and the remedy. A skill stays locked to a host until every verb it needs exists there — missing until somebody lists it on the contract — which is the honest answer rather than a gap, since nothing has yet established which verbs it needs. The migration is deliberately incremental: this record covers the expand step only, no call site moves with it, and contract.json’s skills map is empty until the first skill migrates. This is consistent with ADR-0014 on a different axis: 0014 is about which host program loads the kit, this is about which tracker a repository files against, and the two vary independently — Claude Code against GitLab is as coherent a combination as Codex against GitHub. Reopens when: a second backend lands and the verb table proves to need a shape contract.json cannot express, or when a host’s relation model makes the fallback rule insufficient.