[Doc][Umbrella] Improve Calling LLMs documentation #1232

Parent: #1225

Goal

Improve the Calling LLMs documentation for 0.4 using the page hierarchy delivered by #1244. Organize implementation work by page, keep framework concepts separate from provider capabilities, and give each topic an authoritative explanation with clear links to related pages.

Work items

• [Doc] Improve Chat Models and built-in provider documentation #1248 — Improve Chat Models and built-in provider documentation
• [Doc] Improve Chat with Models and message documentation #1249 — Improve Chat with Models and message documentation
• [Doc] Improve Tool Use documentation #1250 — Improve Tool Use documentation
• [Doc] Improve Skills usage and source-loading documentation #1251 — Improve Skills usage and source-loading documentation
• [Doc] Improve Model Routing examples and behavior reference #1233 — Improve Model Routing examples and behavior reference

Prompts and MCP are included in the final cross-page review. Create additional focused issues only if that review finds substantive gaps; no separate rewrite is required just to mirror every navigation entry.

Coordination and delivery

• The structural PR [docs] Restructure documentation navigation and guides for 0.4 #1244 is merged. The child issues can proceed in parallel against the current page hierarchy, preserving improvements already delivered there.
• [Doc] Improve Chat Models and built-in provider documentation #1248 owns model declaration and provider-specific capabilities, naming, and migration guidance. [Doc] Improve Chat with Models and message documentation #1249 owns ChatMessage, framework content/media semantics, and the chat request/response flow. Coordinate shared capability statements and reciprocal links.
• [Doc] Improve Tool Use documentation #1250 owns Tool Use behavior, parameter-injection explanations, and parallel-call guidance. [Doc] Improve YAML API reference and usage guidance #1231 retains YAML configuration shape, constraints, defaults, and minimal examples. [Doc] Improve consistency, Action State Store, and configuration guidance #1234 retains concise configuration-reference entries and links to the feature guide.
• [Doc] Improve Skills usage and source-loading documentation #1251 owns general Skills configuration and source loading. [Doc] Improve Built-in ReAct Agent usage documentation #1230 retains ReAct-specific configuration, output behavior, and tools/Skills integration examples, linking to the Skills guide for shared concepts.
• [Doc] Improve Model Routing examples and behavior reference #1233 owns the Model Routing guide and coordinates with its existing API trackers. Finalize API-dependent sections against the delivered 0.4 implementation; this does not block unrelated documentation work.
• Apply [Doc] Improve Agent core concepts, Actions, Events, and execution guides #1229's Resource model and [Doc] Clarify API choices, language dimensions, and cross-language contracts #1227's language distinctions consistently. Each review finding has one owning issue; related pages coordinate the necessary supporting edits.

Final cross-page acceptance

• Chat Models, Prompts, Chat with Models, Model Routing, Tool Use, MCP, and Skills form a coherent progression with clear cross-links and no unnecessary duplicated explanations.
• Framework message contracts and provider/model capability limits agree, including multimodal support, source types, and tool calling.
• YAML, ReAct, configuration reference, and Calling LLMs use consistent terminology, defaults, supported APIs, and behavioral constraints.
• Representative examples and Java/Python/YAML support statements match the delivered 0.4 APIs; documentation builds and internal links pass verification, with execution coverage and limitations recorded.

Close this umbrella after its children and the integrated Calling LLMs review are complete. The broader documentation review remains under #1225.

Review coverage

• [Doc] Improve Chat Models and built-in provider documentation #1248: DOC-011, DOC-042, DOC-047.
• [Doc] Improve Chat with Models and message documentation #1249: DOC-043, DOC-044, DOC-045, DOC-046; coordinates provider-side supporting edits with [Doc] Improve Chat Models and built-in provider documentation #1248.
• [Doc] Improve Tool Use documentation #1250: DOC-050; coordinates the Tool Use side of DOC-037, owned by [Doc] Improve YAML API reference and usage guidance #1231.
• [Doc] Improve Skills usage and source-loading documentation #1251: DOC-038, DOC-039, and user guidance associated with the cross-language Skills API work.
• [Doc] Improve Model Routing examples and behavior reference #1233: DOC-048, DOC-049.

The child issues describe their actionable scope independently of the review inventory.