{"record":{"id":"6c5e9c067080f7c3","repo":"alibaba/spring-ai-alibaba","slug":"tool-definition-is-null","errorCode":null,"errorMessage":"Tool definition is null","messagePattern":"Tool definition is null","errorType":"validation","errorClass":"IllegalStateException","httpStatus":null,"severity":"error","filePath":"spring-boot-starters/spring-ai-alibaba-starter-config-nacos/src/main/java/com/alibaba/cloud/ai/agent/nacos/tools/NacosMcpGatewayToolCallback.java","lineNumber":408,"sourceCode":"\n\t@Override\n\tpublic String call(@NonNull final String input) {\n\t\treturn call(input, new ToolContext(Maps.newHashMap()));\n\t}\n\n\t@Override\n\t@SuppressWarnings(\"unchecked\")\n\tpublic String call(@NonNull final String input, final ToolContext toolContext) {\n\t\ttry {\n\t\t\ttry {\n\t\t\t\tlogger.info(\"[call] input: {} toolContext: {}\", input, JacksonUtils.toJson(toolContext));\n\t\t\t} catch (Exception e) {\n\t\t\t\t// Ignore logging errors\n\t\t\t}\n\n\t\t\t// 参数验证\n\t\t\tif (this.toolDefinition == null) {\n\t\t\t\tthrow new IllegalStateException(\"Tool definition is null\");\n\t\t\t}\n\n\t\t\t// input解析\n\t\t\tlogger.info(\"[call] input string: {}\", input);\n\t\t\tMap<String, Object> args = new HashMap<>();\n\t\t\tif (!input.isEmpty()) {\n\t\t\t\ttry {\n\t\t\t\t\targs = objectMapper.readValue(input, Map.class);\n\t\t\t\t\tlogger.info(\"[call] parsed args: {}\", args);\n\t\t\t\t}\n\t\t\t\tcatch (Exception e) {\n\t\t\t\t\tlogger.error(\"[call] Failed to parse input to args\", e);\n\t\t\t\t\t// 如果解析失败，尝试作为单个参数处理\n\t\t\t\t\targs.put(\"input\", input);\n\t\t\t\t}\n\t\t\t}\n\n\t\t\tString protocol = this.toolDefinition.getProtocol();","sourceCodeStart":390,"sourceCodeEnd":426,"githubUrl":"https://github.com/alibaba/spring-ai-alibaba/blob/f82da0b50f35744c13968191be2b1cd2452ef550/spring-boot-starters/spring-ai-alibaba-starter-config-nacos/src/main/java/com/alibaba/cloud/ai/agent/nacos/tools/NacosMcpGatewayToolCallback.java#L390-L426","documentation":"Thrown by NacosMcpGatewayToolCallback.call when its internal toolDefinition field is null at invocation time, an IllegalStateException signaling the callback was not properly initialized. Call cannot proceed to dispatch the MCP request without a tool definition (name, protocol, remote server config).","triggerScenarios":"call(String input) invoked on a callback constructed without a toolDefinition — e.g. built from an incomplete/invalid Nacos MCP service descriptor, or the definition failed to load during bean construction and null was stored.","commonSituations":"Nacos service metadata missing the tool definition fields; building callbacks manually without passing the definition; race or ordering issue where the callback is used before definitions load.","solutions":["Verify how the callback is constructed and ensure a non-null ToolDefinition is supplied.","Check Nacos MCP registry metadata so the service exposes a complete tool definition.","Fail fast at construction: reject null definitions in the constructor instead of at call time.","If definitions load asynchronously, gate usage until initialization completes."],"exampleFix":"// before\ncallback.call(input); // callback built with null definition\n// after: guard at construction\nif (toolDefinition == null) {\n    throw new IllegalArgumentException(\"ToolDefinition must not be null when building NacosMcpGatewayToolCallback\");\n}\nNacosMcpGatewayToolCallback callback = new NacosMcpGatewayToolCallback(toolDefinition, ...);","handlingStrategy":"type-guard","validationCode":"boolean isCallable(NacosMcpGatewayToolCallback cb) {\n    try {\n        Field f = cb.getClass().getDeclaredField(\"toolDefinition\");\n        f.setAccessible(true);\n        return f.get(cb) != null;\n    } catch (ReflectiveOperationException e) { return false; }\n}\n// or expose a getter and check cb.getToolDefinition() != null before call()","typeGuard":"if (callback == null || callback.getToolDefinition() == null) {\n    throw new IllegalStateException(\"Callback not initialized with a tool definition\");\n}","tryCatchPattern":"try {\n    return callback.call(input);\n} catch (IllegalStateException e) {\n    if (\"Tool definition is null\".equals(e.getMessage())) {\n        logger.error(\"Rebuild the callback with a valid ToolDefinition loaded from Nacos\");\n    }\n    throw e;\n}","preventionTips":["Construct callbacks only through factory/registry paths that guarantee a definition.","Validate Nacos MCP metadata completeness at startup.","Fail fast in your own wrapper if the definition is absent before dispatching calls."],"tags":["nacos","mcp","null-check","initialization"],"backgroundTag":"null-argument","analyzedSha":"f82da0b50f35744c13968191be2b1cd2452ef550","analyzedAt":"2026-09-09T15:32:42.421Z","contentChangedAt":"2026-09-09T15:32:42.421Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}