feat(autogen-ext): add VoidlyPay x402 tool

[EmperorMew]

Adds a VoidlyPay extension under autogen-ext that lets AutoGen agents
pay for HTTP 402 endpoints via the x402 protocol.
Sits next to tools/http/ and tools/mcp/ and follows the same
BaseTool + Component-loadable pattern.

Wraps the existing
voidly-pay-autogen
PyPI package when installed (full toolkit), with a self-contained x402
round-trip fallback using
voidly-pay so the tool works
out-of-the-box. Settles in <200ms via a Sourcify-verified USDC vault on
Base mainnet (0xb592...1c12).

Files

• python/packages/autogen-ext/src/autogen_ext/tools/voidly_pay/_voidly_pay.py (new)
• python/packages/autogen-ext/src/autogen_ext/tools/voidly_pay/__init__.py (new)
• python/packages/autogen-ext/tests/tools/voidly_pay/test_voidly_pay.py (new — 5 unit tests)
• python/packages/autogen-ext/tests/tools/voidly_pay/__init__.py (new)

No changes to pyproject.toml — the tool imports voidly_pay and
httpx lazily and reports a clear error on the result model when
either is missing. (Happy to add a voidly-pay extra if maintainers
prefer.)

Tests

5 unit tests, all passing locally. They mock voidly_pay and httpx
to exercise the inline x402 path without network:

• test_tool_schema — args schema correctness
• test_component_round_trip — dump_component / load_component
• test_x402_round_trip_settles — full 402 -> sign -> retry happy path
• test_x402_blocks_when_over_cap — refuses to spend over max_amount_credits
• test_non_402_passthrough — 200 responses bypass payment logic

$ pytest tests/tools/voidly_pay/
========================= 5 passed in 0.18s ==========================

ruff check + ruff format both clean against the project config.

How an AutoGen agent uses it

from autogen_agentchat.agents import AssistantAgent
from autogen_ext.tools.voidly_pay import VoidlyPayTool, VoidlyPayToolConfig

tool = VoidlyPayTool(VoidlyPayToolConfig())
agent = AssistantAgent(
    name="researcher",
    model_client=...,
    tools=[tool],
)

Mint a DID + claim a 10-credit faucet at https://voidly.ai/pay/claim
(no install), then export VOIDLY_PAY_DID + VOIDLY_PAY_SECRET.

Honest scope

Voidly Pay is an open marketplace (anyone can list a paid endpoint at
/pay/list-your-service). Real
volume is small today (~$4 in the vault); the value here is the working
pattern for x402-aware tool design.

CLA

Aware Microsoft requires a CLA. The cla-bot will comment and I'll sign
on the standard flow.

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