Hello, I’m really impressed with DT Herschel and its MCP server.
I’d like to use it to integrate my Hermes Agent, but the DT-connector isn’t provided.
I’m using a local instance of the Hermes Agent server in a pod, installed on Nethserver 8.
How do I integrate it?
We don’t offer per-application support for third-party AI applications.
DEVONthink is looking for a local installation, possibly a ~/.hermes directory, though @cgrunenberg would have to confirm or deny that. Once I did a local install, I had the option enabled…
Only local installations are automatically detected and supported. In all other cases a manual configuration is required. See e.g. DEVONthink MCP with BoltAI2
I’m relieved, having been rather disappointed just now.
I can’t see why I should give up my Hermes Agent Server on the LAN in favour of a local installation on my MacBook.
Have you tried asking Hermes to install it? It can probably figure it out for you.
Thank you for asking. I didn’t have time enough. I will try later.
I tried it. But hermes could noct connect to my local MCP-Server. The reason is probably in the settings:
accept connections: from my Mac only
It’s not changeable to accept connection from my LAN.
Thats the test from my local terminal:
❯ curl -v -H "Authorization: Bearer z99-mytoken-JU" http://127.0.0.1:8420/
* Trying 127.0.0.1:8420...
* Established connection to 127.0.0.1 (127.0.0.1 port 8420) from 127.0.0.1 port 58010
* using HTTP/1.x
> GET / HTTP/1.1
> Host: 127.0.0.1:8420
> User-Agent: curl/8.20.0
> Accept: */*
> Authorization: Bearer z9-mytoken-JU
>
* Request completely sent off
< HTTP/1.1 404 Not Found
< Content-Length: 0
<
* Connection #0 to host 127.0.0.1:8420 left intact
Connections from the local host are not accepted either. Very irritating.
One of the hints in Devonthink: “Connections made from outside this Mac require an access token and a TLS certificate.”
But how am I supposed to import a certificate? That sounds rather complicated, especially as I can only use LE certificates at best.
Connecting from another device generally does require acquiring, installing, and trusting a proper TLS certificate. Self-signed certificates will not work. However, getting one is beyond the scope of our support. There is no one method of doing it and yes, it can be more complex than people may imagine (and not necessarily free).
I have now set up an SSH tunnel from the hermes pod to my laptop.
This means the connection appears as localhost:
Connected (895ms)
59 tools detected
Very nice.
I couldn’t find a description of the MCP API.
So I asked Hermes-Agent 
The 59 MCP tools cover seven functional areas:
===== 2.1 Databases & Navigation (6 tools) =====
| Tool | Description |
|---|---|
| ‘‘get_databases’’ | Retrieve all open DEVONthink databases (uuid, name, configuration) |
| ‘‘get_record_children’’ | List children of a group folder (with pagination for large groups) |
| ‘‘get_group_tree’’ | Retrieve the complete sub-tree structure of a group as JSON — one call instead of N repetitions |
| ‘‘get_record_parents’’ | Determine parent groups of a record (navigation Up) |
| ‘‘get_record_properties’’ | Retrieve all metadata of a record (uuid/single or uuids/batch, max 500) |
| ‘‘is_running’’ | Check whether DEVONthink is running on the Mac |
===== 2.2 Search & Lookup (9 Tools) =====
| Tool | Description |
|---|---|
| ‘‘search_records’’ | Full-text search using DEVONthink’s own query syntax (Boolean operators, field filters) |
| ‘‘lookup_records’’ | Lookup via ‘‘name’’, ‘‘URL’’, ‘‘path’’, ‘‘filename’’ or ‘‘comment’’ |
| ‘‘get_record_duplicates’’ | Find duplicates based on the content hash |
| ‘‘find_similar_records’’ | Find records similar to a reference document or text (DEVONthink AI) |
| ‘‘get_current_record’’ | Retrieve the record currently open in the DEVONthink Viewer |
| ‘‘get_selected_records’’ | Retrieve the records currently selected in DEVONthink |
| ‘‘get_record_links’’ | List incoming/outgoing links between records |
| ‘‘get_record_external_references’’ | Extract external links (URLs) from documents, grouped by schema |
| ‘‘get_record_unlinked_wiki_links’’ | Find wiki link names that do not refer to any existing record |
===== 2.3 Creating & editing records (6 tools) =====
| Tool | Description |
|---|---|
| ‘‘create_record’’ | Create a new record in DEVONthink (text, PDF, HTML, image, etc.) |
| ‘‘update_record’’ | Change properties: Name, Comment, URL, Rating, Label, Flag, Lock, Unread, Date |
| ‘‘update_record_content’’ | Update text content (modes: append, insert, replace) |
| ‘‘create_group_path’’ | Create folder hierarchy like ‘‘mkdir -p’’ — all intermediate groups are created |
| ‘‘merge_records’’ | Merge multiple records into a single document (PDF, images → PDF, RTF) |
| ‘‘set_record_annotation’’ | Create or update an annotation (note) on a record |
===== 2.4 Move, copy & delete (7 tools) =====
| Tool | Description |
|---|---|
| ‘‘move_record’’ | Move records to another group (including across databases) |
| ‘‘duplicate_record’’ | Duplicate records into a target group |
| ‘‘replicate_record’’ | Replicate records within the same database |
| ‘‘trash_record’’ | Move records to the Trash |
| ‘‘export_record’’ | Export records to the file system |
| ‘‘import_file’’ | Import or index files/folders into DEVONthink |
| ‘‘get_imported_record_path’’ | Retrieve the on-disk path of imported records |
===== 2.5 Reading & Extracting Content (6 Tools) =====
| Tool | Description |
|---|---|
| ‘‘get_record_text’’ | Retrieve the raw text of a text-based record |
| ‘‘extract_record_content’’ | Extract text optimised for AI consumption (optionally with a metadata preamble) |
| ‘‘extract_record_visuals’’ | Extract visual content as images for vision models (photos, diagrams, screenshots) |
| ‘‘extract_record_highlights’’ | All annotations of a dataset as a Markdown summary |
| ‘‘extract_record_mentions’’ | Find mentions of a dataset in OTHER documents |
| ‘‘get_record_thumbnails’’ | Retrieve thumbnails as base64 JPEGs |
===== 2.6 Editing & converting content (5 tools) =====
| Tool | Description |
|---|---|
| ‘‘convert_record’’ | Convert records to a different format (PDF → DOCX, HTML → PDF, etc.) |
| ‘‘ocr_record’’ | Perform OCR on images or scanned PDFs (creates a searchable PDF) |
| ‘‘transcribe_record’’ | Transcribe audio/video records using DEVONthink AI |
| ‘‘summarize_record_highlights’’ | Summarise a document’s annotations as a new record |
| ‘‘summarize_record_mentions’’ | Summarise mentions of a record in other documents |
===== 2.7 Tags & Metadaten (11 Tools) =====
| Tool | Description |
|---|---|
| ‘‘get_record_tags’’ | Retrieve tags of a record |
| ‘‘set_record_tags’’ | Set/replace/add/remove tags (mode: replace, add, remove) |
| ‘‘list_database_tags’’ | List all tags defined in a database |
| ‘‘get_record_custom_metadata’’ | Retrieve custom metadata fields |
| ‘‘set_record_custom_metadata’’ | Set custom metadata fields |
| ‘‘list_custom_metadata_fields’’ | List all user-defined custom metadata fields |
| ‘‘get_record_annotation’’ | Retrieve UUID of a record’s annotation |
| ‘‘get_record_reminder’’ | Retrieve a record’s reminder |
| ‘‘set_record_reminder’’ | Set a reminder |
| ‘‘clear_record_reminder’’ | Remove a reminder |
| ‘‘get_record_versions’’ | Retrieve the version history of a record |
===== 2.8 AI Features (3 Tools) =====
| Tool | Description |
|---|---|
| ‘‘classify_record’’ | AI-assisted categorisation — DEVONthink suggests the best group |
| ‘‘research_topic’’ | Topic research via DEVONthink AI: databases + web + Wikipedia + arXiv + PubMed |
| ‘‘chat_response’’ | One-off prompt to DEVONthink’s configured AI (engine follows user settings) |
===== 2.9 Web & external sources (5 tools) =====
| Tool | Description |
|---|---|
| ‘‘capture_web_page’’ | Save a web page to DEVONthink as HTML, Web Archive, Markdown or PDF |
| ‘‘download_pdf_from_doi’’ | Resolve a DOI and download an open-access PDF via CrossRef + Unpaywall |
| ‘‘resolve_doi_metadata’’ | Resolve DOI to bibliographic metadata (title, authors, journal, year) |
| ‘‘search_crossref’’ | Search the CrossRef database for journal articles, books and conference papers |
| ‘‘resolve_book_metadata’’ | Retrieve book metadata via Google Books and Open Library |
===== 2.10 Miscellaneous (1 tool) =====
| Tool | Description |
|---|---|
| ‘‘open_record’’ | Open record in DEVONthink (launches DEVONthink if necessary) |