Agents

Constructing an agent

The verified constructor takes an ISessionService:

await using var agent = new Agent(new InMemorySessionService())
{
    Model = provider.CreateLanguageModel("claude-sonnet-4-5-20250929"),
    SystemPrompt = "You are a helpful assistant."
};

Key configuration properties

Important runtime knobs on Agent include:

• Model as either an ILanguageModel instance or a string model ID
• SystemPrompt
• ContextBuilder
• Temperature
• MaxTokens
• Thinking
• ProviderOptions
• Tools
• ToolTimeout
• WorkingDirectory
• MaxIterations
• ContinueOnMaxTokens
• UseStreaming
• AutoCompaction
• SubAgents
• Presets
• McpServers
• CliToolDirs, CliTools, SkillDirs, and SkillProvider

Model resolution

Model accepts either:

• a live ILanguageModel
• a string model ID such as claude-sonnet-4-5
• an explicit provider-prefixed string like anthropic:claude-sonnet-4-5

Samples usually create a provider first and call provider.CreateLanguageModel(...).

Presets and sub-agents

Full child agents can be assigned via SubAgents. Lightweight named delegation configs can be assigned via Presets.

Presets can define:

• AllowedTools
• Model
• MaxIterations
• Temperature
• Thinking

The parent agent materializes them on demand during delegation.

Working directory

Set WorkingDirectory when built-in file tools, memory, or other local operations need a concrete workspace boundary.

Thread-safety

Agent instances are not thread-safe. Use one active invocation per instance.