workflow: make the local world's files interchangeable with the TypeScript SDK

[fantix]

The local world used to write CBOR into files named .json. TypeScript's @workflow/world-local writes real JSON, so neither side could read the other's .workflow-data tree.

Now Python writes what TS JSON.stringify(value, jsonReplacer, 2) writes:

​json { "runId": "wrun_01KZ7ARFVCB83N043NCT1SG49R", "status": "running", "input": { "__type": "Uint8Array", "data": "ZGV2bFtbXV0=" }, "attributes": {}, "startedAt": "2026-08-04T21:27:02.766Z" } ​

• two-space indent, non-ASCII unescaped
• bytes in the {__type, data} base64 wrapper
• datetime as toISOString(), three fractional digits
• integral floats as plain integers
• unset fields omitted, never null

null is the one that bites: TS types output, error and completedAt as z.undefined(), which rejects it, and its date fields use z.coerce.date(), so a null startedAt would read back as the epoch.

Three field sets differed and are now aligned: runs always carry attributes (copied forward on lifecycle transitions), hooks carry isSystem, tokens carry the eventId TS claim recovery reads back.

End-to-end Test PoC

Second commit: a real Python workflow runs end to end against a real LocalWorld, then the TS workflow CLI reads back what it wrote.

# workflow inspect run <id> --backend local --json
assert run["input"] == [{"amount": 21}]
assert run["output"] == "charged 42"

CI installs the CLI in its own step and points VERCEL_WORKFLOW_CLI at it. Locally it installs on demand and skips without node.

Breaking

Existing .workflow-data directories are unreadable in the new format and should be deleted.

[vercel]

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Project	Deployment	Actions	Updated (UTC)
vercel-py	Ready	Preview	Aug 5, 2026 2:27am