docs(sdk): add new field-based features

.github/workflows/check-broken-links.yml

@@ -34,7 +34,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: '20'
+          node-version: '22'
 
       - name: Install Mint CLI
         run: npm install -g mint@latest

sdk/guides/agent-file-based.mdx

@@ -1,6 +1,6 @@
 ---
 title: File-Based Agents
 description: Define specialized sub-agents as simple Markdown files with YAML frontmatter — no Python code required.
 ---
 
 import RunExampleCode from "/sdk/shared-snippets/how-to-run-example.mdx";
@@ -13,7 +13,7 @@
 
 ## Agent File Format
 
 An agent is a single `.md` file with YAML frontmatter and a Markdown body:
 
 ```markdown icon="markdown"
 ---
@@ -40,16 +40,18 @@
 Keep feedback concise and actionable. For each issue, suggest a fix.
 ```
 
 The YAML frontmatter configures the agent. The Markdown body becomes the agent's system prompt.
 
 ### Frontmatter Fields
 
 | Field | Required | Default | Description |
 |-------|----------|---------|-------------|
 | `name` | Yes | - | Agent identifier (e.g., `code-reviewer`) |
 | `description` | No | `""` | What this agent does. Shown to the orchestrator |
 | `tools` | No | `[]` | List of tools the agent can use |
-| `model` | No | `"inherit"` | LLM model (`"inherit"` uses the parent agent's model) |
+| `model` | No | `"inherit"` | LLM model profile to load and use for the subagent (`"inherit"` uses the parent agent's model) |
+| `skills` | No | `[]` | List of skill names for this agent (see [Skill Loading Precedence](/overview/skills#skill-loading-precedence) for resolution order). |
+| `max_iteration_per_run` | No | `None`| Maximum iterations per run. Must be strictly positive, or `None` for the default value. |
 | `color` | No | `None` | [Rich color name](https://rich.readthedocs.io/en/stable/appendix/colors.html) (e.g., `"blue"`, `"green"`) used by visualizers to style this agent's output in terminal panels |
 
 ### `<example>` Tags
@@ -160,7 +162,7 @@
 print(f"Registered {len(agent_names)} agents: {agent_names}")
 ```
 
 This scans both project-level and user-level directories, deduplicates by name, and registers each agent as a delegate that can be spawned by the orchestrator.
 
 ## Manual Loading
 
@@ -212,7 +214,7 @@
 ```
 
 The factory:
 - Maps tool names from the frontmatter to `Tool` objects
 - Appends the Markdown body to the parent system message via `AgentContext(system_message_suffix=...)`
 - Respects the `model` field (`"inherit"` keeps the parent LLM; an explicit model name creates a copy)