[ChahatKumar]

This supersedes #73783 from a writable fork and includes the original implementation together with the failing-test correction, rebased onto current main.

Python tasks fail before their task body runs when Dag run conf contains an integer such as 18446744073709551616. The Execution API preserves the value, but encoding the supervisor startup message raises OverflowError because it exceeds MessagePack's native integer range.

This preserves those values across Python subprocess communication using a MessagePack extension with a signed binary payload. Both directions restore the original Python int, including nested values. External language-SDK subprocesses retain their existing behavior.

The additional test fix accounts for MySQL JSON's integer range: values below signed 64-bit minimum or above unsigned 64-bit maximum remain covered on PostgreSQL and SQLite, while MySQL continues to cover its native boundaries and a large numeric string.

Validation on the exact current-main branch in the Airflow Linux CI image:

• Task SDK coordinator, communication, and supervisor suites: 496 passed, 1 skipped
• SQLite large-integer Execution API regression cases: 5 passed
• Earlier focused MySQL regression: 3 passed, 2 correctly backend-skipped
• Ruff formatting and lint passed
• git diff --check passed

The PR changes exactly eight files covering the original feature and its tests; no Dag Processor compatibility files are included because current main already contains #74731.

closes: #73712

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Was generative AI tooling used to co-author this PR?

• Yes — GitHub Copilot

[boring-cyborg]

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[ashb]

@ChahatKumar There was activity on this PR yesterday by the original poster, so no, opening a new PR is not appropriate.