feat: add generate_object tool for structured JSON output

Add a built-in `generate_object` tool that produces schema-validated JSON
objects from any LLM provider. Features:

- Four output modes: tool-call (default), prompt, strict, json
- Robust JSON extraction from dirty LLM output (code fences, prose)
- Streaming partial objects via tool_output_delta events
- Automatic repair loop with schema validation feedback
- Built-in JSON Schema validator (anyOf/oneOf, nullable, pattern, ranges)
- Cross-provider: works with Anthropic, OpenAI, and OpenAI-compatible APIs

Includes 70 unit tests + 4 integration tests against real MiniMax API,
Node.js SDK integration test (6 cases), and Python SDK integration test
(6 cases).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: claude

CHANGELOG.md

@@ -7,6 +7,28 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [2.4.0] - 2026-05-11
+
+### Added
+
+- Added `generate_object` built-in tool for structured JSON output with schema
+  validation, automatic repair, and streaming partial objects. Works across all
+  providers via tool-calling mode.
+- Added `llm::structured` module with four output modes (tool, prompt, strict,
+  json), robust JSON extraction from dirty LLM output, partial JSON parser for
+  streaming, and a built-in JSON Schema validator supporting `anyOf`/`oneOf`,
+  nullable types, `additionalProperties`, `pattern`, and numeric ranges.
+- Added streaming partial object support: `generate_object` emits
+  `tool_output_delta` events with progressively complete JSON snapshots.
+- Added comprehensive documentation: structured output example (EN/CN), contract
+  review tutorial (EN/CN), and 7 additional core mechanism tutorials (PTC,
+  streaming, session persistence, skills, MCP, security/HITL, hooks, memory).
+
+### Fixed
+
+- Fixed Shiki build error in docs site caused by unsupported `acl` language
+  identifier in code blocks (replaced with `text`).
+
 ## [2.3.0] - 2026-05-09
 
 ### Added

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "a3s-code-core"
-version = "2.3.0"
+version = "2.4.0"
 edition = "2021"
 authors = ["A3S Lab Team"]
 license = "MIT"

core/Cargo.toml

@@ -60,6 +60,9 @@ pub(super) fn build_session_capabilities(input: SessionCapabilityInput<'_>) -> S
         &tool_executor,
     );
 
+    // Register generate_object tool (structured JSON output)
+    crate::tools::register_generate_object(tool_executor.registry(), Arc::clone(&input.llm_client));
+
     register_mcp_capabilities(
         &tool_executor,
         input.opts,

core/src/agent_api/capabilities.rs

@@ -7,6 +7,7 @@ pub mod anthropic;
 pub mod factory;
 pub mod http;
 pub mod openai;
+pub mod structured;
 mod types;
 pub mod zhipu;