Claude 7fff4ddb99 Add structured-output module: entity() mapping to records/lists/maps, StructuredOutputValidationAdvisor retries
ChatClient.CallResponseSpec.entity() mapping LLM JSON to a record (TicketTriage, with a real
enum-constrained Priority field), a List<ActionItem>, and a Map<String,Object> -- every case driven
by a hand-written ScriptedChatModel with no live LLM anywhere.

Key findings, all confirmed by disassembling spring-ai-client-chat-2.0.1.jar and spring-ai-model-2.0.1.jar
rather than trusting docs:

- StructuredOutputValidationAdvisor lives in org.springframework.ai.chat.client.advisor, in the same
  spring-ai-client-chat artifact as ToolCallingAdvisor -- unlike the tool-calling module's Tool Search
  Advisor pieces, it needs no separate Maven Central artifact or version pin.
- entity(Class, spec -> spec.validateSchema()) is sugar: DefaultCallResponseSpec.resolveAdvisorChain
  builds a real StructuredOutputValidationAdvisor from the same JSON schema BeanOutputConverter uses
  to parse the response, and pushes it onto the advisor chain for that one call.
- The schema/format instructions are baked into the user message once, up front, by entity() itself,
  before the advisor chain runs at all. A validation retry's only contribution is one appended line:
  "Output JSON validation failed because of: <the real schema-validator error>" -- each retry
  re-augments the ORIGINAL request, not the previous attempt's, so corrections never stack.
- Default maxRepeatAttempts is 3 (4 total attempts); default advisorOrder is 2147481647, near
  Ordered.LOWEST_PRECEDENCE.
- Exhausting every retry does NOT throw -- adviseCall's loop just returns the last (still invalid)
  response to the caller. Plain entity() with no validation, by contrast, throws immediately on the
  same bad JSON, since BeanOutputConverter.convert() is a separate Jackson deserialization step with
  no retry loop of its own. Both behaviors are captured from real runs (output/02, output/06).
- Spring AI 2.0's JSON stack is Jackson 3 (tools.jackson.databind), not classic com.fasterxml.jackson --
  visible directly in every one of this advisor's constructor and field signatures.

Companion module for "Structured Output in Spring AI 2.0: Records, JSON Schema and Self-Correcting
Responses" on ankurm.com.

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01FtpJvZfg4nvLvtzgJTDWpB
2026-09-23 17:18:32 +00:00

spring-ai

Runnable companion code for the Spring AI articles on ankurm.com. One directory per module; each module is one commit and carries its own README, tests and captured output.

Module What it is Article
getting-started/ One ChatClient bean, three endpoints (plain call, templated system prompt, streaming), and a test proving spring.ai.model.chat switches providers with zero code change. Spring Boot 4.1.1, Spring AI 2.0.1, Java 25. Spring AI 2.0 in 10 Minutes: ChatClient on Spring Boot 4.1
rag/ Ingest PDFs, chunk, retrieve from pgvector, rerank, answer, check the answer. Spring Boot 4.1.1, Spring AI 2.0.1, Java 25. Production-grade RAG with Spring AI and the complete example
mcp-server/ An order-lookup service exposed as MCP tools, a resource, and a prompt with @McpTool/@McpResource/@McpPrompt, served over Streamable HTTP (Spring AI 2.0's default MCP server transport). Spring Boot 4.1.1, Spring AI 2.0.1, Java 25. Build an MCP Server with Spring AI 2.0
mcp-client/ ChatClient calling tools from two real external MCP servers (filesystem, git) over stdio via defaultToolCallbacks(ToolCallbackProvider...), contrasted with a local @Tool method, with every call logged through one Micrometer ObservationHandler. Spring Boot 4.1.1, Spring AI 2.0.1, Java 25. Spring AI MCP Client: Calling External MCP Servers from ChatClient
mcp-secure/ The mcp-server article's order-lookup tools behind a real OAuth2 resource server: JWT validation, one scope per tool via @PreAuthorize, unauthenticated tool discovery rejected outright, and every call audit-logged through MDC -- denials included. Spring Boot 4.1.1, Spring AI 2.0.1, Spring Security 7.1.1, Java 25. Securing an MCP Server with Spring Security 7
tool-calling/ @Tool methods, ToolCallingAdvisor (the advisor-layer replacement for Spring AI 1.x's per-model tool loop), returnDirect, ToolContext, and ToolSearchToolCallingAdvisor for progressive disclosure across a 230-tool synthetic library -- every test driven by a hand-written ScriptedChatModel, no live model anywhere. Spring Boot 4.1.1, Spring AI 2.0.1, Java 25. Tool Calling in Spring AI 2.0
structured-output/ ChatClient.entity() mapping LLM responses to Java records, lists and maps; StructuredOutputValidationAdvisor retrying non-conforming JSON with a real enum-constrained schema, including a captured run that exhausts every retry without throwing. Spring Boot 4.1.1, Spring AI 2.0.1, Java 25. Structured Output in Spring AI 2.0

Upgrading from Spring AI 1.x: migration guide.

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Runnable companion code for the Spring AI articles on ankurm.com
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