# Per-Node SDK Callbacks in Archon Workflows: Complete Hook Reference

> Explore 21 per-node SDK callback hooks in Archon workflows like PreToolUse and SessionStart. Intercept Claude Agent SDK events with regex matchers & static JSON responses for powerful control.

- Repository: [Cole Medin/Archon](https://github.com/coleam00/Archon)
- Tags: api-reference
- Published: 2026-04-10

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**Archon supports 21 distinct per-node SDK callback hooks—including `PreToolUse`, `PostToolUseFailure`, `SessionStart`, and `PermissionRequest`—that allow workflow nodes to intercept Claude Agent SDK events through optional regex matchers and static JSON responses.**

The **coleam00/Archon** workflow engine enables granular control over AI agent execution by defining **per-node SDK callbacks** directly within your DAG (directed acyclic graph) configuration. These hooks, validated against strict Zod schemas in the source code, map one-to-one to the