fix(ReActAgent): preserve user chunk callback when using copied toolkit

[JGoP-L]

AgentScope-Java Version

1.0.10-SNAPSHOT

Description

Fixes #870.

Previously, when a user configured a chunk callback via Toolkit#setChunkCallback(...) and then passed that toolkit into ReActAgent.builder().toolkit(toolkit).build(), the callback could be overwritten by the internal callback registered by ReActAgent during tool execution.

This PR separates user-defined chunk callbacks from framework-internal chunk callbacks so both can work together:

• preserve user callbacks across Toolkit.copy()
• keep ActingChunkEvent emission in ReActAgent
• add a regression test in ToolEmitterIntegrationTest

How to test

mvn -pl agentscope-core -Dtest=ToolEmitterIntegrationTest test

[Copilot]

Pull request overview

Fixes a regression where user-configured Toolkit#setChunkCallback(...) was effectively overwritten by ReActAgent during tool execution, ensuring both user chunk callbacks and ActingChunkEvent hook emission work simultaneously (issue #870).

Changes:

• Split tool chunk callback handling into user vs framework-internal callbacks in ToolExecutor.
• Added Toolkit#setInternalChunkCallback(...) so ReActAgent can emit ActingChunkEvent without overwriting user callbacks.
• Preserved user chunk callbacks across Toolkit.copy() and added a regression test covering the real ReActAgent copied-toolkit scenario.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
agentscope-core/src/main/java/io/agentscope/core/tool/ToolExecutor.java	Separates user/internal chunk callbacks and composes an effective callback for ToolEmitter.
agentscope-core/src/main/java/io/agentscope/core/tool/Toolkit.java	Adds internal chunk-callback API and preserves user chunk callback during copy().
agentscope-core/src/main/java/io/agentscope/core/ReActAgent.java	Registers an internal chunk callback (instead of overwriting the user callback) to emit ActingChunkEvent.
agentscope-core/src/test/java/io/agentscope/core/tool/ToolEmitterIntegrationTest.java	Adds integration regression test verifying both user callback and ActingChunkEvent receive tool-emitted chunks under ReActAgent.

[Copilot]

Toolkit#setInternalChunkCallback(...) is a public method but appears intended as framework-only API. In this codebase, similar public-but-internal APIs (e.g., Toolkit#callTools(...)) are explicitly labeled in Javadoc as “Internal API - Not recommended for external use.” Consider adding the same explicit warning here to discourage external callers and set expectations about API stability.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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