Structured output and tool invocation

### Checked other resources - [x] This is a feature request, not a bug report or usage question. - [x] I added a clear and descriptive title that summarizes the feature request. - [x] I used the GitHub search to find a similar feature request and didn't find it. - [x] I checked the LangChain documentation and API reference to see if this feature already exists. - [x] This is not related to the langchain-community package. ### Package (Required) - [x] langchain - [x] langchain-openai - [ ] langchain-anthropic - [ ] langchain-classic - [ ] langchain-core - [ ] langchain-cli - [ ] langchain-model-profiles - [ ] langchain-tests - [ ] langchain-text-splitters - [ ] langchain-chroma - [ ] langchain-deepseek - [ ] langchain-exa - [ ] langchain-fireworks - [ ] langchain-groq - [ ] langchain-huggingface - [ ] langchain-mistralai - [ ] langchain-nomic - [ ] langchain-ollama - [ ] langchain-perplexity - [ ] langchain-prompty - [ ] langchain-qdrant - [ ] langchain-xai - [ ] Other / not sure / general ### Feature Description Currently, there is a conflict between the structured output of create_agent and the tool call. Can it be optimized in this direction: 1. Place the restrictions on the structured output at the last output. 2. Set structured output for the tool. Within the agent, the llm can call different tools and use different structured outputs as the input for the tool functions. A bit of insight, I wonder if it's feasible. ### Use Case The tool I invoked requires strictly structured input, which llm cannot achieve when calling ### Proposed Solution Currently, there is a conflict between the structured output of create_agent and the tool call. Can it be optimized in this direction: 1. Place the restrictions on the structured output at the last output. 2. Set structured output for the tool. Within the agent, the llm can call different tools and use different structured outputs as the input for the tool functions. A bit of insight, I wonder if it's feasible. ### Alternativ…