# Let plugins register tools for the built-in MCP server (Tier 3 of the AI sidebar spec)

**URL:** <https://discourse.joplinapp.org/t/let-plugins-register-tools-for-the-built-in-mcp-server-tier-3-of-the-ai-sidebar-spec/51172>\
**Category:** Features\
**Created:** [7 October 2026 06:13 UTC](https://discourse.joplinapp.org/t/let-plugins-register-tools-for-the-built-in-mcp-server-tier-3-of-the-ai-sidebar-spec/51172 "2026-10-07T06:13:45Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![gerard.kieffer](https://avatars.discourse-cdn.com/v4/letter/g/b782af/32.png) [@gerard.kieffer](https://discourse.joplinapp.org/u/gerard.kieffer)\
**Post date:** [7 October 2026 06:13 UTC](https://discourse.joplinapp.org/t/let-plugins-register-tools-for-the-built-in-mcp-server-tier-3-of-the-ai-sidebar-spec/51172/1 "2026-10-07T06:13:45Z")

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Bonjour everyone,

Thanks for the built-in MCP server in 3.7, it works well.

But the set of MCP tools is fixed. Useful additions like listing backlinks, finding orphan notes or broken links, editing a specific section of a long note,they would require changing Joplin core. The only alternative today would be running a second MCP server next to the built-in one, (extra setup, duplicated tools ).

**Proposal**

Implement plugin tool registration as described in the AI sidebar spec (`ai_sidebar_tools.md`, "Tier 3 — Plugin-registered tools") ,so plugin tools appear both in the AI sidebar and through `/mcp`.

In v3.7.21 and on `dev`, `ToolIndex` only contains the built-in and editor tools, and `JoplinAi` has no way to register tools. Since the sidebar and the MCP server already share `ToolIndex`, this would mostly mean adding plugin tools to it and bridging calls to the plugin sandbox.

**some questions**

1. Is Tier 3 still planned, and is anyone working on it?
2. How should plugin tools fit with the per-tool settings (e.g. ID prefixed with the plugin ID, disabled by default) ?
3. Could a first version skip the custom `render` part ?

Merci!

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**Author:** ![laurent](https://avatars.discourse-cdn.com/v4/letter/l/ce7236/32.png) [@laurent](https://discourse.joplinapp.org/u/laurent)\
**Post date:** [7 October 2026 08:23 UTC](https://discourse.joplinapp.org/t/let-plugins-register-tools-for-the-built-in-mcp-server-tier-3-of-the-ai-sidebar-spec/51172/2 "2026-10-07T08:23:28Z")

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What tools in particular do you think would be needed? Could you provide a list? I think we could simply add them for now as the MCP feature is quite new so it's possible it's missing essential tools

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**Author:** ![gerard.kieffer](https://avatars.discourse-cdn.com/v4/letter/g/b782af/32.png) [@gerard.kieffer](https://discourse.joplinapp.org/u/gerard.kieffer)\
**Post date:** [7 October 2026 08:52 UTC](https://discourse.joplinapp.org/t/let-plugins-register-tools-for-the-built-in-mcp-server-tier-3-of-the-ai-sidebar-spec/51172/3 "2026-10-07T08:52:01Z")

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Thank you ! Here's my list. It's a very personal selection, based on how I use Joplin, and other Notes apps together with AI chatbots.

**Related to navigation:**

1. **`get_links`** (note\_id) - Outgoing links and backlinks of a note. In order to give AI the possibility to follow connections between notes having to search every time.
2. **`related_notes`** (note\_id): notes semantically similar to a given note, using the existing embeddings. This matches the "AI-generated note graphs" use case in the AI primitives spec.

**improvements for long notes** :

1. Section support in `read_note`. Possibility to return to the note's outline (headings only), and a `section` parameter to read a single heading's content. This saves tokens on long notes.
2. Section support in `update_note`: append or replace content under a given heading, so the AI doesn't need to resend or `replace_text` the whole body.

**Efficiency**

1. **`read_notes`** (note\_ids): read several notes in one call, to save round trips after a search.

**Maintenance** (lower priority)

1. **`find_broken_links`** and **`find_orphan_notes`** : internal links pointing to missing notes, and notes with no links in or out.

A few smaller server-side suggestions, not tools:

- Accept the token in an `Authorization: Bearer` header, not only in the URL.
- Add MCP tool annotations (`readOnlyHint`, `destructiveHint`) so clients can skip confirmations for read-only tools.
- Return compact JSON instead of pretty-printed JSON to save tokens.
- "search\_notes" loads the full body of every match before applying limit (it only needs bodies for the returned snippets), which may be slow on broad queries in large collections..

C'est tout 🙂  
Adding these to core would be great.

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**Author:** ![laurent](https://avatars.discourse-cdn.com/v4/letter/l/ce7236/32.png) [@laurent](https://discourse.joplinapp.org/u/laurent)\
**Post date:** [7 October 2026 15:16 UTC](https://discourse.joplinapp.org/t/let-plugins-register-tools-for-the-built-in-mcp-server-tier-3-of-the-ai-sidebar-spec/51172/4 "2026-10-07T15:16:43Z")

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Thanks for the feedback, I think some of these makes sense so I've started creating a few issues for it:

> **[Issues · laurent22/joplin](https://github.com/laurent22/joplin/issues?q=is%3Aissue+state%3Aopen+label%3AAI)**
>
> Joplin - the privacy-focused note taking app with sync capabilities for Windows, macOS, Linux, Android and iOS. - Issues · laurent22/joplin

Looks GitHub is falling apart at the moment so I can't add more for now, but I will later when it's back