Goose Hooks Reference

Disclaimer: This document reflects our current understanding of Goose’s extensibility surface. It is a working reference for symposium development, not a substitute for the official docs. Details may be outdated or incomplete — always consult the primary sources.

Primary sources: Extensions · Configuration · GitHub repo

Goose does not implement lifecycle hooks. There are no shell-command or programmatic interception points for tool execution, session start/stop, or prompt submission. No hooks.json equivalent. No JSON stdin/stdout protocol.

What Goose Offers Instead

MCP Extensions

The primary extensibility mechanism. Extensions are MCP servers (stdio or HTTP) that expose new tools, resources, and prompts. Configured in ~/.config/goose/config.yaml under extensions:. Built-in extensions include Developer (shell, file editing), Computer Controller, Memory, and Todo. Custom extensions are standard MCP servers built in Python, TypeScript, or Kotlin. Extensions add capabilities but cannot intercept or modify existing tool behavior.

Permission Modes

The closest analog to hook-based control flow. Static configuration, not programmable logic.

Mode	Behavior
`auto`	Tools execute without approval (default)
`approve`	Every tool call requires manual confirmation
`smart_approve`	AI risk assessment auto-approves low-risk, prompts for high-risk
`chat`	No tool use

Per-tool permissions can be set to Always Allow, Ask Before, or Never Allow.

Goosehints / AGENTS.md

Instruction files injected into the system prompt. Influence LLM behavior through prompting, not deterministic interception.

File	Scope
`~/.config/goose/.goosehints`	Global
`.goosehints` (project root)	Project
`AGENTS.md`	Project

GOOSE_TERMINAL Environment Variable

Shell scripts can detect whether they’re running under Goose and alter behavior (e.g., wrapping git to block git commit). This is a shell-level workaround, not a Goose-native mechanism.

Other Mechanisms

.gooseignore — gitignore-style file access restriction
Recipes — YAML workflow packages
Custom slash commands
Subagents
ACP integration
Tool Router — internal optimization for tool selection

MCP Server Registration

Since Goose has no lifecycle hooks, symposium integrates exclusively via MCP server registration. Symposium registers itself as an extension in the Goose config file.

Configuration structure

The MCP server entry is added under extensions in the YAML config:

extensions:
  symposium:
    provider: mcp
    config:
      command: /path/to/cargo-agents
      args: [mcp]

Project-level: .goose/config.yaml
User-level: ~/.config/goose/config.yaml

Registration is idempotent — if the entry already exists with the correct values, no changes are made. Stale entries are updated in place.

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