---
title: "Tool annotations: definition and example | Agent MCP Directory"
description: "Tool annotations: Hints on a tool such as readOnlyHint and destructiveHint that tell clients how risky a call is. Defined with a sourced example."
canonical: https://agentmcpdirectory.com/glossary/tool-annotations
site: "Agent MCP Directory"
last_updated: 2026-11-04
section: "Glossary"
---

# Tool annotations: definition and example | Agent MCP Directory

> Tool annotations: Hints on a tool such as readOnlyHint and destructiveHint that tell clients how risky a call is. Defined with a sourced example.

Source: https://agentmcpdirectory.com/glossary/tool-annotations
Site: Agent MCP Directory
Last reviewed: 2026-11-04

# Tool annotations

Tool annotations: Hints on a tool such as readOnlyHint and destructiveHint that tell clients how risky a call is. Example: Claude's directory requires a title and readOnlyHint or destructiveHint on every tool. Next in the glossary is WebMCP: A draft browser API for pages to register JavaScript tools that an in-browser agent can call.

## Definition

Hints on a tool such as readOnlyHint and destructiveHint that tell clients how risky a call is.

## Example, with source

Claude's directory requires a title and readOnlyHint or destructiveHint on every tool. ([claude.com](https://claude.com/docs/connectors/building/submission), read 4 November 2026)

## Where it appears on this site

-   [Getting listed in registries](https://agentmcpdirectory.com/guides/get-listed-in-registries/)
-   [Tool descriptions and agent success](https://agentmcpdirectory.com/guides/tool-descriptions-and-agent-success/)

## Neighbouring terms

-   [Tool](https://agentmcpdirectory.com/glossary/mcp-tool/): A function an MCP server offers for the model to call, with a name, description and input schema.
-   [WebMCP](https://agentmcpdirectory.com/glossary/webmcp/): A draft browser API for pages to register JavaScript tools that an in-browser agent can call.

Edition

4 November 2026

Method

[How rows are verified](https://agentmcpdirectory.com/method/)

Data

[CSV and JSON](https://agentmcpdirectory.com/data/)

Markdown

[This page as markdown](https://agentmcpdirectory.com/glossary/tool-annotations/index.md)

## Sources

-   [Source for the Tool annotations example](https://claude.com/docs/connectors/building/submission), read 4 November 2026

Last reviewed 4 November 2026