Python: Handle dict input for MagenticStartMessage

[tonybaloney]

Fixes #1310

[markwallace-microsoft]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
packages/core/agent_framework/_workflows
_magentic.py	969	244	74%	58–67, 72, 76–87, 316, 341, 346–347, 423, 427, 441, 447, 462, 542, 555, 572, 581–582, 584–586, 588, 599, 666–670, 673–677, 757–760, 763–767, 769–771, 778, 817, 864, 900–902, 904, 1011, 1047, 1056–1058, 1076–1077, 1079–1080, 1099, 1144, 1147, 1175, 1178, 1183, 1191–1195, 1201, 1219–1220, 1231–1233, 1235, 1237, 1245–1250, 1252, 1256–1257, 1260–1263, 1265–1266, 1272–1274, 1277–1278, 1283–1284, 1292, 1304–1305, 1316, 1328, 1340–1343, 1372–1373, 1378–1380, 1414, 1438, 1455, 1471, 1481, 1495, 1554, 1560–1561, 1575, 1577, 1580, 1582–1583, 1586–1587, 1591, 1594, 1615, 1650–1651, 1653, 1657–1658, 1676–1677, 1687–1688, 1703, 1708–1711, 1790–1791, 1795, 1810, 1814–1815, 1819–1820, 1837, 1840, 1864–1865, 1876, 1879–1886, 1894–1898, 1907–1908, 1962–1964, 2001, 2012, 2023–2025, 2055–2057, 2068–2070, 2083–2085, 2088–2091, 2111, 2115, 2119–2120, 2137, 2144, 2147, 2151, 2156, 2193–2196, 2207–2210, 2222–2225, 2234–2237, 2252, 2256
TOTAL	10363	1708	83%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
1276	98 💤	0 ❌	0 🔥	26.860s ⏱️

[Copilot]

Pull Request Overview

This PR adds support for handling dictionary input when starting a Magentic workflow, specifically for dictionaries containing an "input" key. The change allows the workflow to accept dictionary messages and extract the text content from the "input" field.

• Added dictionary input handling for MagenticStartMessage creation
• Extracts text from dict["input"] and converts it to a MagenticStartMessage using the existing from_string method

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[Copilot]

The dict input handling lacks validation. Consider validating that message['input'] is a string before passing it to from_string(), as the method expects a string parameter but could receive any type from the dict.

Suggested change

	elif isinstance(message, dict) and "input" in message:
	elif isinstance(message, dict) and "input" in message:
	if not isinstance(message["input"], str):
	raise TypeError(f"Expected 'input' to be a string, got {type(message['input']).__name__}")

[moonbox3]

Hi @tonybaloney, thanks for working on this. I've done some refactoring to improve the orchestration start message types for Magentic, Concurrent, and Sequential patterns to be more reflective of agent patterns (and the input types they accept). This now allows for DevUI to properly introspect the Magentic input message type.

You can find this in an open PR I have: #1538