Interfaces
Interface: RuntimeConfig
Generated from the public TypeScript API.
Per-session runtime configuration applied to each accepted turn. Local
callbacks stay in the SDK process; the server stores serializable descriptors.
Runtime configuration is ephemeral and must be supplied after a server restart.
Session-scoped helper and subagent definitions, keyed by name.
Nonempty tool allowlist, including scoped expressions such as bash(npm:). An empty array adds no allowlist restriction; use disallowedTools: [""] to hide ordinary tools. Matching grants can bypass the permission callback.
Append application instructions after the selected base system prompt.
Provider/model used to classify unresolved permissions in auto mode.
V2 awaits tasks within the current turn. Detached durable jobs are outside this release.
Answer unresolved tool approval requests. Explicit allow rules can approve a tool before this callback runs. Set false to disable a prior callback on resume.
Fine-grained file checkpoint policy.
Programmatic commands invoked by Session.command(name, arguments).
Per-session automatic compaction and summary formatting.
Tool denylist. [”*”] disables tool execution, including the runtime’s StructuredOutput tool. Use deterministic deny rules for operations that must never be approved.
Provider-specific reasoning effort; unsupported combinations are rejected.
Enable automatic file checkpointing. Requires a Git-backed workspace with runtime snapshots enabled.
Control deferred tool discovery. Directly loaded tools remain governed by normal tool policy.
Callbacks keyed by lifecycle event. Callbacks remain local and must be rebound after restarting the application. An empty object clears prior hooks on resume.
Include working directory and platform context in the model’s system prompt.
Full custom system prompt (sugar for a custom systemPrompt). Cannot be combined with systemPrompt.
Positive estimated USD budget; a reached limit ends with error_max_budget. Provider accounting is authoritative.
Positive maximum number of assistant turns before error_max_turns.
Provider/model identifier used for the main agent turn.
Expected structured JSON output schema and bounded schema retry policy.
Approval policy for unresolved tool requests. This does not create an OS sandbox.
Inline plugin bundles or local Claude-format plugin directories.
SDK-hosted or external MCP descriptors. An explicit empty array clears prior MCP registrations on resume.
Instruction/config resource sources to load. SDK sessions default to an empty array.
Programmatic reusable skill descriptions and content.
Replace the base prompt with a string/custom prompt, or explicitly select the coding preset.
Provider reasoning configuration; unsupported model/provider combinations fail explicitly.