exo:hooks

Intercept Exo agent lifecycle events and runtime mutations via HookPoint registrations.

1|Updated Feb 16, 2026
One-click install
npx skills add https://github.com/midsphere-ai/exo --skill exo-hooks
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: exo:hooks
Source: https://github.com/midsphere-ai/exo/tree/main/skills/hooks
Command: npx skills add https://github.com/midsphere-ai/exo --skill exo-hooks

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Exo developers need a reliable mechanism to observe, influence, and mutate agent executions without embedding logic in core components.

Core Features & Use Cases

  • HookPoint-based interception across START, PRE/POST_LLM_CALL, PRE_TOOL_CALL, FINISHED, ERROR, and CONTEXT_WINDOW.
  • Runtime mutation of tools, handoffs, and MCP servers, plus message injection for live steering.
  • Use cases include observability, safety rails, dynamic tool loading, and ephemeral context injection for targeted steps.

Quick Start

Register a simple START hook to log the event and demonstrate adding a tool during a run.

Frequently Asked Questions about exo:hooks

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I add observability to agent lifecycles without changing core components?▼

You can add observability to agent lifecycles by registering HookPoint interceptions across events like START, PRE_LLM_CALL, and FINISHED to monitor runs externally without modifying core logic.

Can I dynamically mutate tools and inject messages during a live agent run?▼

Yes, you can dynamically mutate tools, handoffs, and MCP servers during a live agent run by using runtime mutation methods and ephemeral message injection via async hooks.

What lifecycle events are available for interception when controlling agent runs?▼

Available lifecycle events for interception include START, PRE and POST LLM_CALL, PRE_TOOL_CALL, FINISHED, ERROR, and CONTEXT_WINDOW, enabling precise control across execution stages.

How do I register a hook to log agent lifecycle events and add a tool at runtime?▼

Register a simple START hook via the HookManager API to log the event and demonstrate adding a tool during a run, applying async hook safety semantics for reliable execution.

When should I use hookpoints to build safety rails for agent executions?▼

Use hookpoints to build safety rails when you need to intercept PRE_TOOL_CALL or ERROR events, allowing you to block unsafe actions or inject corrective context dynamically during execution.

Do I need async hooks to handle runtime mutations across agent runs?▼

Yes, runtime mutations across agent runs require async hooks to ensure safety semantics and non-blocking execution when intercepting lifecycle events or mutating tools dynamically.