The workflow command was asking the model to parse $ARGUMENTS into
positional tokens (issue ID, optional base branch). Opencode supports
$1, $2, $3, ... for direct positional substitution at template-load
time — the model never needs to see or parse a joined argument string.
Two simplifications:
1. Replace $ARGUMENTS-parsing with $1. Every reference to the issue ID
in commands/workflow.md is now $1, which opencode substitutes
literally before the prompt loads. Eliminates a class of parsing
errors (whitespace edge cases, mis-splits, hallucinated extra args)
and removes the orchestrator's need to "remember" an ISSUE_ID
variable across phases.
2. Drop BASE_BRANCH entirely. It was used in three places:
- Phase 1 "branch != base" check — actual concern is "don't run on
a protected branch." Replace with refusal on main/master/develop/
any matching protected name.
- Phase 8 `git diff "$BASE_BRANCH"...HEAD` — anchor the diff to
START_SHA captured at Phase 1 instead. With one-task-per-run
(ADR-21), the run produces a small bounded diff from a known
starting point; START_SHA is more accurate than diffing against
a separate branch tip that may have moved.
- Failure Handler recovery procedure — user-facing instructions;
name "your usual integration branch" instead of $BASE_BRANCH.
The command signature collapses from `/workflow <ISSUE-ID> [base-branch]`
to just `/workflow <ISSUE-ID>` — single positional, zero parsing.
Routing matrix Phase 1 row updated for the protected-branch refusal;
ADR-14's recovery-procedure paragraph no longer names BASE_BRANCH.
Refs: config/opencode/workflow-design.md ADR-14, ADR-21