fix(tool): tolerate stringified nested-union tool arguments - #298
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This was referenced Aug 16, 2026
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Closes #297
Summary
qwen-family models string-encode tool-argument containers whose schema is a nested union (
{"params": "{\"action\": \"list\"}"}), making theworkflowtool completely unusable on those models. Verified end-to-end: opencode's schema generation and parse pipeline are innocent; the wire capture shows the model emitting the double-encoded string; controlled A/B proves only the union shape on qwen triggers it.Change
tool.ts: strict decode first; on failure only, a lenient retry re-parses string values that sit where a container is expected (repairStringifiedContainers), then lets the normal decode judge the result. Legitimate strings are never touched because the retry only runs after strict decoding failed.Verification
test/tool/tool-define.test.ts(repair round-trip, unrepairable still rejects, JSON-looking plain strings untouched); suite 9/9.bun typecheckclean frompackages/opencode.Merge note
Precondition for the DAG dogfood path (issues #293/#294/#296 follow-ups): the running binary needs rebuild + restart before the workflow tool works on qwen-family models. Suggest merging this first among the harness batch.