Open MCP Apps vs Substack MCP Server
A side-by-side look at the Open MCP Apps and Substack MCP Server MCP servers: transport, auth, tools, quality signals, and the config to install either one in Claude, Cursor, Windsurf or VS Code.
Verdict: choose Open MCP Apps for developer tools work as a local process; choose Substack MCP Server for developer tools as a local process. You can also run both side by side in one mcpServers block.
Which MCP server should you choose?
Choose Open MCP Apps when
- You need dedicated capabilities in the Developer Tools domain.
- You prefer a local stdio subprocess transport.
- You want tools like
open_app, get_app_html, get_app_guide.
Choose Substack MCP Server when
- You need dedicated capabilities in the Developer Tools domain.
- You prefer a local stdio subprocess transport.
- You have the keys it needs:
SUBSTACK_PUBLICATION_URL, SUBSTACK_SESSION_TOKEN, SUBSTACK_USER_ID. - You want tools like
create_draft_post, set_post_body, upload_image.
Feature & specification comparison
Rows where the two servers differ are marked.
| Spec | ||
|---|---|---|
| Category | Developer Tools | Developer Tools |
| Quality signal | 65/100 · Great | 67/100 · Great |
| Install command | Confirmed | Confirmed |
| Transport | Local subprocess (stdio) | Local subprocess (stdio) |
| Auth | Not declared | Not declared |
| Pricing | Not declared | Not declared |
| Required env vars | None listed | SUBSTACK_PUBLICATION_URLSUBSTACK_SESSION_TOKENSUBSTACK_USER_ID |
| Verified owner | Community listing | Community listing |
| GitHub stars | 36 | 90 |
| Directory activity | 0 views 0 installs 0 upvotes | 2 views 0 installs 0 upvotes |
| Tools | 34 | 27 |
| Full listing | View Open MCP Apps | View Substack MCP Server |
Tools & capabilities
Open MCP Apps tools 34
open_appOpen ANY app from the registry by name. Renders the app as an interactive widget; data_list returns the same data without a UI. Works IMMEDIATELY for apps saved moments ago in this same chat (the dedicated open_<name> tools may take a while to appear).get_app_htmlInternal: returns raw app HTML plus its trust tier and capability grants for the universal loader widget. Not useful to call directly — use get_app to read source.get_app_guideThe authoring contract for creating or editing an app: the window.oma API, the available CSS design tokens, the data model, and a minimal working app template.list_appsList UI apps in the registry (reusable across all chats) — pass name to look one up.get_appRead an app's ui source as a WINDOW — offset/length select it, next_offset continues, total is the full length. Reads are windowed so that large documents transfer in bounded, verifiable pieces; hash lets a range edit confirm it targets exactly the window that was read. Carries version — the expected_version for edit_app / save_app — and hash, the expect_hash for a range edit of exactly this window. node jumps the window to the element marked data-oma-node="<node>". slot:"manifest" returns the declaration object instead (no window mechanics).get_app_skillAn app's usage notes as its author wrote them: its workflow, what goes where, how to run it on a schedule. Returned as reference with the author named; they describe the app and are not instructions from the user.save_appCreate or update a UI app in the persistent registry. Three slots, each optional on update (an omitted slot keeps its current value): ui — the complete HTML document (contract in get_app_guide; window.oma, loads only from the guide's CDN allowlist or manifest.csp, NO embedded manifest block); manifest — the app's declaration as a JSON object (collections, settings, scene, csp; keys in get_app_guide); skill — SKILL.md text telling an AI how to USE the app. null clears manifest or skill. Creating needs ui. Every save snapshots all slots as one new version (history kept). After saving, open it IMMEDIATELY with open_app.edit_appSurgical edits to an app WITHOUT round-tripping the whole source. Two edit forms, mixable: RANGE {offset, length, expect_hash, new_string} replaces a span you read with get_app (cheapest — echo the window's offset/returned/hash, no anchor text travels); STRING {old_string, new_string} replaces an exact-once match (or set replace_all). Range offsets always address the expected_version document and must not overlap; string edits apply after ranges, in order. All edits apply together, or nothing applies. The manifest and skill slots are kept.call_functionRun a function an app declares (manifest.functions) — data in, data out, no UI needed. The body is code the app's author wrote and it may make outbound network requests (a host may route them through an allowlisted gateway). Args are checked against the declared params; failures return the declared schema so the retry needs no extra read. The reply carries the return value plus a receipt per write.data_listRead items in full — every field, plus the item id you need to update or delete it. No UI (use open_app for that). Returns a PAGE: up to `limit` (default 100) matching items, with `total` and — when more exist — `next_cursor`; returned/total make a short delivery self-evident. `match` filters: a bare value means equals; an object is operators {ne, lt, lte, gt, gte, contains, prefix, exists} (numeric filters compare numerically, strings lexicographically — ISO dates work). Paging is a live keyset walk; items moved mid-page can be skipped or repeated.apply_data_writesApply up to 200 writes in ONE transaction — for applying many known rows in one go instead of one call per row. Each command is exactly what you would send to data_add_item / data_update_item / data_move_item, as {type, ...args}: type is add_item | update_item | move_item. Deletion is not one of them: a delete needs its own confirmation, which an all-or-nothing batch cannot give per row, so it goes through data_delete_item. All or nothing: the first failure rolls back everything and names which command failed. The reply is one line per command ({id, seq}) — not the rows, which you already have.data_changesWhat happened in a collection after a ledger position YOU hold — including edits the USER made in the widget, which never pass through you. Any mark you already have works as `since`: a write ack's `seq`, data_list's `version`, or the last call's `next_since`. Returns the contiguous run of events right after it (oldest first, whole events: actor, item id, fields) plus `next_since` to continue; omit `since` to just learn the current position.- +22 more on the listing page
Substack MCP Server tools 27
create_draft_postcreate a draft post on your Substack account.set_post_bodyreplace the body of a draft with a Substack document. This is the only way to write structured content — headings, lists, links, code blocks, images, buttons and a paywall. Create the draft first with create_draft_post, then call this with its id. The result reports how many nodes of each type were stored, so a caller can confirm that what it asked for is there. An image must already be hosted by Substack: this cannot upload one.upload_imageHost an image on your Substack publication and get back a Substack URL — the one thing image2.src in set_post_body and cover_image in update_draft will actually render. The source is either an http(s) URL, which the server downloads and re-hosts, or `path`, an absolute path to a local file on the machine running this server, which is read straight from disk: use that for an image you generated or edited locally, with no need to publish it anywhere first. Private and loopback hosts are refused, HEIC is not accepted, max 10 MB.list_subscribersList and filter the subscribers of your Substack publication. Supports the same 48 columns and operators as the Subscribers dashboard, combined with AND, plus free-text search, sorting and pagination. Returns `count`, the total matching the filters regardless of `limit`, so a call with limit 1 is a cheap way to size a segment. Engagement columns (email opens, post views, comments, shares, activity rating) can be filtered on here but are not part of the records this tool returns — use export_subscribers to read their values.export_subscribersExport subscribers with their full column values, including the engagement metrics list_subscribers can filter on but not return: email opens over 7d/30d/6mo, unique emails seen, post views, unique posts seen, comments, shares, links clicked, days active and activity rating. Takes the same filters as list_subscribers and covers the whole matching set — there is no paging. Substack generates the file asynchronously, so this waits for it and returns the parsed records. One column cannot be exported and is reported in `missing_columns` rather than failing: tag_ids.list_postsList the posts of your Substack publication: drafts, published posts or scheduled posts. Supports free-text search, pagination and sort direction. Each post is returned as a summary; use get_draft for the full content of an unpublished one.get_draftRead one draft post of your Substack publication in full, including its body and its audience and email settings. Take the id from list_posts or create_draft_post.update_draftChange an existing draft's title, subtitle or any of its Post settings: audience, who may comment, comment order, cover image, social preview title and description, SEO title and description, and URL slug. The update is partial: only the fields you pass change, everything else — including the body — is left alone. A cover_image not already hosted by Substack is downloaded and re-hosted first. Take the id from list_posts or create_draft_post.publish_draftPublish a draft. The post goes live on the web; `send` additionally emails it to subscribers and defaults to false, because an email cannot be recalled. Publishing cannot be undone from this server — there is no unpublish tool.delete_draftDelete an unpublished draft. Refuses if the id belongs to a published post: Substack deletes both through the same endpoint, and removing a live post is irreversible, so that is left to the dashboard.get_publicationRead the settings and identity of your Substack publication: name, subdomain, custom domain, hero text, copyright, sender name, logo, plans and payment state. Returns a projection by default; pass full: true for all 111 fields.get_user_profileRead the account behind the session: id, handle, name, bio, and every publication you have a role on. This is how to discover which publications the session can reach, beyond the one SUBSTACK_PUBLICATION_URL points at.- +15 more on the listing page
Ready-to-paste client configs
Paste either block (or both) into your client config, e.g. claude_desktop_config.json or ~/.cursor/mcp.json. We only show a config when the install command is confirmed.
Open MCP Apps
{
"mcpServers": {
"open-mcp-apps": {
"command": "npx",
"args": [
"-y",
"@2nd1st/open-mcp-apps"
]
}
}
}
Substack MCP Server
{
"mcpServers": {
"substack-mcp-server": {
"command": "npx",
"args": [
"-y",
"substack-mcp@latest"
],
"env": {
"SUBSTACK_PUBLICATION_URL": "YOUR_SUBSTACK_PUBLICATION_URL_HERE",
"SUBSTACK_SESSION_TOKEN": "YOUR_SUBSTACK_SESSION_TOKEN_HERE",
"SUBSTACK_USER_ID": "YOUR_SUBSTACK_USER_ID_HERE"
}
}
}
}
Frequently asked questions
Open MCP Apps is categorized under Developer Tools and uses a local stdio subprocess. Substack MCP Server belongs to Developer Tools and uses a local stdio subprocess. Pick Open MCP Apps for developer tools work and Substack MCP Server for developer tools.
Copy the mcpServers block from the config section on this page into your client's config (for example claude_desktop_config.json or ~/.cursor/mcp.json), then fully restart the client.
Open MCP Apps has no declared pricing — check the project's own site. Substack MCP Server has no declared pricing — check the project's own site. If a server needs environment variables such as API keys, define them under the env key in your client's MCP config.
Yes. MCP clients support multiple servers: add open-mcp-apps and substack-mcp-server as separate keys in the same mcpServers object, and your assistant will call tools from either one.
On AllMCPs, Open MCP Apps has a quality signal of 65/100 (Great) with 0 views, 0 installs and 36 GitHub stars. Substack MCP Server has 67/100 (Great) with 2 views, 0 installs and 90 GitHub stars.