Substack by Cotlet
REMOTE · COTLET.DEV · 3 COMPONENTS
Posts, Notes, messages, subscribers and stats for your publication.
Available components
Last scanned (2 hours ago)
Scores higher than 60% of remote servers
Reachable. Last reached 24 Oct 2026.
Category Marketing and SEO
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security66
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation check failed: no authorisation is required to call this server, and it exposes a tool marked destructive (cotlet_browser_click). See how to fix → View diagnostics → Fail
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- The HSTS (Strict-Transport-Security) header is present. View diagnostics → Pass
- DNSSEC is configured correctly; the domain's records validate against the full chain to the root. View diagnostics → Pass
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability84
- 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).Pass
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 7845 tokens (~115/item across 68 items; 67 tools + 1 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management0
- Stability check failed: schema churn in the 1 day we've observed: 3 tool removals, 0 breaking changes, 0 auth/transport breaks, 0 additions. See how to fix → Fail
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- All 8 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation.Pass
- An AI judge read all 69 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a current MCP spec version (2026-07-28).Pass
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 24 Oct 26 +1
- Stability: unverified → fail ▼ security
- A breaking change shipped without a version bump: still 0.1.0 ▼ security
- Tool “cotlet_balance” was removed ▼ security
- Tool “cotlet_browser_connect” was removed ▼ security
- Tool “cotlet_browser_sessions” was removed ▼ security
- The server rewrote its instructions, which are the text every model session reads security
- Tool “add_subscriber” rewrote its description, which is the text the model reads security
- Tool “cancel_scheduled_post” rewrote its description, which is the text the model reads security
- Tool “cotlet_browser_click” rewrote its description, which is the text the model reads security
- Tool “cotlet_browser_close” rewrote its description, which is the text the model reads security
- Tool “cotlet_browser_navigate” rewrote its description, which is the text the model reads security
- Tool “cotlet_browser_open” rewrote its description, which is the text the model reads security
- Tool “cotlet_browser_press” rewrote its description, which is the text the model reads security
- Tool “cotlet_browser_read” rewrote its description, which is the text the model reads security
- Tool “cotlet_browser_screenshot” rewrote its description, which is the text the model reads security
- Tool “cotlet_browser_scroll” rewrote its description, which is the text the model reads security
- Tool “cotlet_browser_select” rewrote its description, which is the text the model reads security
- Tool “cotlet_browser_type” rewrote its description, which is the text the model reads security
- Tool “cotlet_browser_upload” rewrote its description, which is the text the model reads security
- Tool “create_draft” rewrote its description, which is the text the model reads security
- Tool “create_post_tag” rewrote its description, which is the text the model reads security
- Tool “create_subscriber_tag” rewrote its description, which is the text the model reads security
- Tool “delete_comment” rewrote its description, which is the text the model reads security
- Tool “delete_post” rewrote its description, which is the text the model reads security
- Tool “duplicate_post” rewrote its description, which is the text the model reads security
- Tool “export_subscribers” rewrote its description, which is the text the model reads security
- Tool “follow_user” rewrote its description, which is the text the model reads security
- Tool “get_audience_insights” rewrote its description, which is the text the model reads security
- Tool “get_conversation” rewrote its description, which is the text the model reads security
- Tool “get_daily_stats” rewrote its description, which is the text the model reads security
- Tool “get_feed” rewrote its description, which is the text the model reads security
- Tool “get_post” rewrote its description, which is the text the model reads security
- Tool “get_post_engagement” rewrote its description, which is the text the model reads security
- Tool “get_post_stats” rewrote its description, which is the text the model reads security
- Tool “get_post_traffic” rewrote its description, which is the text the model reads security
- Tool “get_publication_stats” rewrote its description, which is the text the model reads security
- Tool “get_unread_counts” rewrote its description, which is the text the model reads security
- Tool “like_comment” rewrote its description, which is the text the model reads security
- Tool “like_post” rewrote its description, which is the text the model reads security
- Tool “list_activity” rewrote its description, which is the text the model reads security
- Tool “list_comments” rewrote its description, which is the text the model reads security
- Tool “list_conversations” rewrote its description, which is the text the model reads security
- Tool “list_note_replies” rewrote its description, which is the text the model reads security
- Tool “list_notes” rewrote its description, which is the text the model reads security
- Tool “list_post_tags” rewrote its description, which is the text the model reads security
- Tool “list_posts” rewrote its description, which is the text the model reads security
- Tool “list_recommendations” rewrote its description, which is the text the model reads security
- Tool “list_sections” rewrote its description, which is the text the model reads security
- Tool “list_subscriber_tags” rewrote its description, which is the text the model reads security
- Tool “list_subscribers” rewrote its description, which is the text the model reads security
- Tool “list_subscriptions” rewrote its description, which is the text the model reads security
- Tool “list_traffic_sources” rewrote its description, which is the text the model reads security
- Tool “pin_comment” rewrote its description, which is the text the model reads security
- Tool “publish_note” rewrote its description, which is the text the model reads security
- Tool “publish_post” rewrote its description, which is the text the model reads security
- Tool “recommend_publication” rewrote its description, which is the text the model reads security
- Tool “remove_comment” rewrote its description, which is the text the model reads security
- Tool “remove_subscriber” rewrote its description, which is the text the model reads security
- Tool “reply_to_comment” rewrote its description, which is the text the model reads security
- Tool “reply_to_note” rewrote its description, which is the text the model reads security
- Tool “schedule_post” rewrote its description, which is the text the model reads security
- Tool “search_substack” rewrote its description, which is the text the model reads security
- Tool “send_message” rewrote its description, which is the text the model reads security
- Tool “tag_post” rewrote its description, which is the text the model reads security
- Tool “unpublish_post” rewrote its description, which is the text the model reads security
- Tool “update_draft” rewrote its description, which is the text the model reads security
- Tool “tag_subscribers” rewrote its description, which is the text the model reads security
- Schema quality: pass → fail ▼ functional
- Stability: unverified → 0.03 ▲ functional
- Schema quality: good → excellent functional
- 23 Oct 26 69
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 24 Oct 2026 · Probed https://cotlet.dev/mcp/v1/substack
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=cotlet.dev | CN=YE1,O=Let's Encrypt,C=US | 12 Oct 2026 | 10 Jan 2027 | ECDSA 256 | ECDSA-SHA384 | 6afd7585ee8e24a40f5683c10835ec990a8 |
| SANs: *.cotlet.dev, cotlet.dev | ||||||
| CN=YE1,O=Let's Encrypt,C=US (CA) | CN=Root YE,O=ISRG,C=US | 3 Sept 2025 | 2 Sept 2028 | ECDSA 384 | ECDSA-SHA384 | 5ddd70dd31f801c85c186a7a04b80afe |
| CN=Root YE,O=ISRG,C=US (CA) | CN=ISRG Root X2,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | ECDSA-SHA384 | 872165fc34b6e5fba8add5b3705fb53a |
| CN=ISRG Root X2,O=Internet Security Research Group,C=US (CA) | CN=ISRG Root X1,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | SHA256-RSA | 6c8f1dc727c7117f7baf853ac980f9cd |
Background: What to check on a remote MCP endpoint →
DNSSEC secure
Validation of cotlet.dev. — Secure
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| dev. | present | 60074 | 8 | Verified |
| cotlet.dev. | present | 2371 | 13 | Verified |
| cotlet.dev. | Verified address RRset verified with the apex keys |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
| Header | Value |
|---|---|
| strict-transport-security | max-age=31536000; includeSubDomains |
| x-content-type-options | nosniff |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://cotlet.dev/mcp/v1/substack | Verified | 200 | |
| http (plaintext) | http://cotlet.dev/mcp/v1/substack | HTTPS enforced | 301 | https://cotlet.dev/mcp/v1/substack |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
list_subscriptions List subscriptions ~78
Publications you subscribe to, with your plan and whether their emails reach you. Returns every publication your account subscribes to, as Settings > Subscriptions lists them: name, link, plan (free, paid, comp, founding or gift, as Substack names the membership) and whether you get its emails. Your own publications are left out.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
list_traffic_sources List traffic sources ~110
Where your publication's visitors came from in a period, most views first. Returns Analytics > Traffic > Traffic sources: each source (the app, email, a website, search, social) with its category, views, unique visitors and the free and paid subscribers it brought. Sorted by views; page with next_cursor.
| Name | Type | Req | Description |
|---|---|---|---|
| cursor | string | – | next_cursor from the previous page. |
| limit | integer | – | Default: 20. |
| period | string | – | Default: 30d. |
No output schema declared.
No examples provided.
pin_comment Pin comment ~89
Pin a comment to the top of your post's comments, or unpin it. Pins one comment on a post of your publication above all others, as Pin in the comment menu does, or unpins it. A comment on someone else's post returns an error.
| Name | Type | Req | Description |
|---|---|---|---|
| comment_id | string | yes | Comment ID from list_comments. |
| unpin | boolean | – | Unpin instead. Default: false. |
No output schema declared.
No examples provided.
publish_note Publish Note ~169
Short post in Substack Notes, now or at a set time, optionally with a link card to one of your posts. Posts a Note under your name. Without publish_at it goes out now; with it, the Note waits in your scheduled Notes, status is scheduled and published_at is that time. Text is 1 to 1,000 characters. link_post_id must be a published post. By default you confirm each call; you can switch that off for this tool. Waits for the owner's approval.
| Name | Type | Req | Description |
|---|---|---|---|
| body | string | yes | Note text, up to 1,000 characters. |
| link_post_id | string | – | Attach one of your published posts as a link card. |
| publish_at | string | – | ISO 8601 with time zone. Omit to post now. |
No output schema declared.
No examples provided.
publish_post Publish post ~176
Publish a draft now. Publishes a draft immediately, on the web and, unless send_email is false, by email, to the audience set on the draft. Substack's own pre-publish check runs first; a missing title or an empty body stops the call. A sent email cannot be recalled. On a publication with sections the post goes to section_id, else to the section already set on the draft, else to the main publication. By default you confirm each call; you can switch that off for this tool. Waits for the owner's approval.
| Name | Type | Req | Description |
|---|---|---|---|
| post_id | string | yes | Post ID from list_posts. |
| section_id | string | – | Section ID from list_sections, or main. Default: the draft's section, else main. |
| send_email | boolean | – | Email it to subscribers. Default: true. |
No output schema declared.
No examples provided.
recommend_publication Recommend publication ~143
Recommend another publication to your readers, or stop recommending it. Adds a publication to your Recommendations, as Growth > Recommendations does: Substack suggests it to people who subscribe to you and notifies its author. blurb is the short reason readers see. With remove it takes the recommendation back. By default you confirm each call; you can switch that off for this tool. Waits for the owner's approval.
| Name | Type | Req | Description |
|---|---|---|---|
| blurb | string | – | Why you recommend it, shown to your readers (optional). |
| publication_id | string | yes | Publication ID, e.g. from search_substack posts. |
| remove | boolean | – | Stop recommending it instead. Default: false. |
No output schema declared.
No examples provided.
remove_comment Remove comment ~111
Remove someone's comment from your post as the publication's moderator. Hides a comment on a post of your publication, as Remove in the comment menu does: readers see that a moderator removed it, the text is gone, replies under it stay. Use delete_comment for your own comments. A comment on someone else's post returns an error. By default you confirm each call; you can switch that off for this tool. Waits for the owner's approval.
| Name | Type | Req | Description |
|---|---|---|---|
| comment_id | string | yes | Comment ID from list_comments. |
No output schema declared.
No examples provided.
remove_subscriber Remove subscriber ~114
Remove one email from your subscriber list. Removes a subscriber from your list, as Remove in the subscriber's menu does: they get no more emails from you and no notice. A paid subscription is cancelled and Substack refunds the unused part. An email not on your list returns an error; add_subscriber takes about a minute before the address is listed. By default you confirm each call; you can switch that off for this tool. Waits for the owner's approval.
| Name | Type | Req | Description |
|---|---|---|---|
| string | yes | Subscriber's email address. |
No output schema declared.
No examples provided.
reply_to_comment Reply to comment ~110
Reply as you under a comment on your post. Posts a reply under one comment on a post of your publication, under your name, visible to everyone who can read the post. A comment elsewhere on Substack returns an error. The author gets Substack's usual reply notification. By default you confirm each call; you can switch that off for this tool. Waits for the owner's approval.
| Name | Type | Req | Description |
|---|---|---|---|
| body | string | yes | Reply text. |
| comment_id | string | yes | Comment ID from list_comments. |
No output schema declared.
No examples provided.
reply_to_note Reply to Note ~138
Reply as you under any Note or Note reply. Posts a reply under a Note (yours or anyone's) or under a reply to one, visible to everyone who sees the Note. Text is 1 to 1,000 characters; Markdown bold, italics and links work. The author gets Substack's usual notification. By default you confirm each call; you can switch that off for this tool. Waits for the owner's approval.
| Name | Type | Req | Description |
|---|---|---|---|
| body | string | yes | Reply text, up to 1,000 characters. |
| note_id | string | yes | Note ID from list_notes, list_note_replies or search_substack. |
No output schema declared.
No examples provided.
schedule_post Schedule post ~224
Publish a draft at a set time, on the web and by email. Schedules a draft to go live at the time you set, on the web and, unless send_email is false, by email, to the audience set on the draft. The time needs a time zone and must be in the future. Substack's own pre-publish check runs first; a missing title or an empty body stops the call. A scheduled post stays editable until it goes out. On a publication with sections the post goes to section_id, else to the section already set on the draft, else to the main publication. By default you confirm each call; you can switch that off for this tool. Waits for the owner's approval.
| Name | Type | Req | Description |
|---|---|---|---|
| post_id | string | yes | Post ID from list_posts. |
| publish_at | string | yes | ISO 8601 with time zone. |
| section_id | string | – | Section ID from list_sections, or main. Default: the draft's section, else main. |
| send_email | boolean | – | Email it to subscribers. Default: true. |
No output schema declared.
No examples provided.
search_substack Search Substack ~104
Search all of Substack for people, posts and Notes. Runs Substack's search as the search box does and splits the results into people, posts and Notes. Use the IDs with follow_user, like_post, like_comment, reply_to_note, send_message or recommend_publication. Page with next_cursor; later pages may hold only posts and Notes.
| Name | Type | Req | Description |
|---|---|---|---|
| cursor | string | – | next_cursor from the previous page. |
| query | string | yes | Words to search for. |
No output schema declared.
No examples provided.
send_message Send message ~159
Send a direct message on Substack, in a conversation or to a person. Sends a private chat message under your name. With conversation_id it replies there; with user it writes to that person, in your existing conversation with them or a new one. Someone who does not follow you gets it as a message request. Give one of conversation_id or user. A sent message cannot be recalled. By default you confirm each call; you can switch that off for this tool. Waits for the owner's approval.
| Name | Type | Req | Description |
|---|---|---|---|
| body | string | yes | Message text. |
| conversation_id | string | – | Reply in this conversation from list_conversations. |
| user | string | – | Or start one with this handle (e.g. @mayachen) or user ID. |
No output schema declared.
No examples provided.
tag_post Tag post ~101
Add a tag to a post, or take it off. Puts one of your post tags on a draft or published post, or removes it with remove. A post can have several tags. Tagging twice keeps one tag.
| Name | Type | Req | Description |
|---|---|---|---|
| post_id | string | yes | Post ID from list_posts. |
| remove | boolean | – | Take the tag off instead. Default: false. |
| tag_id | string | yes | Tag ID from list_post_tags or create_post_tag. |
No output schema declared.
No examples provided.
tag_subscribers Tag subscribers ~125
Put a tag on subscribers by email, or take it off. Adds one of your subscriber tags to up to 50 subscribers, or removes it with remove. Emails not on your list come back in not_found and nothing else fails. A subscriber added a minute ago may not be findable yet; try again shortly.
| Name | Type | Req | Description |
|---|---|---|---|
| emails | array | yes | Subscribers' email addresses, up to 50. |
| remove | boolean | – | Take the tag off instead. Default: false. |
| tag_id | string | yes | Tag ID from list_subscriber_tags or create_subscriber_tag. |
No output schema declared.
No examples provided.
unpublish_post Unpublish post ~125
Take a published post off the web and back to drafts. Turns a published post back into a draft, as Unpublish in the editor does: it leaves your site, archive and the Substack app, and its link stops working. Comments and stats stay with the draft. Emails already sent stay in inboxes. Publish it again with publish_post. A post that is not published returns an error. By default you confirm each call; you can switch that off for this tool. Waits for the owner's approval.
| Name | Type | Req | Description |
|---|---|---|---|
| post_id | string | yes | Post ID from list_posts. |
No output schema declared.
No examples provided.
update_draft Update draft ~113
Change the title, subtitle, body or audience of a draft. Changes the fields you pass and leaves the others as they are. body_markdown replaces the whole body. Drafts and scheduled posts only: a published post returns an error. Nothing reaches your subscribers, so it runs without asking.
| Name | Type | Req | Description |
|---|---|---|---|
| fields | string | yes | JSON object with any of title, subtitle, body_markdown, audience, e.g. {"title": "New title"}. |
| post_id | string | yes | Post ID from list_posts. |
No output schema declared.
No examples provided.
How do I install the Substack by Cotlet MCP server?
Substack by Cotlet is a hosted endpoint at https://cotlet.dev/mcp/v1/substack, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · cotlet.dev
claude mcp add --transport http dev-cotlet-substack 'https://cotlet.dev/mcp/v1/substack'
What is the Substack by Cotlet MCP server?
Substack by Cotlet is an MCP server listed in the public MCP registry as dev.cotlet/substack. Posts, Notes, messages, subscribers and stats for your publication. This page covers its hosted endpoint (https://cotlet.dev/mcp/v1/substack).
Is the Substack by Cotlet MCP server safe to use?
Substack by Cotlet scores 70 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the Substack by Cotlet MCP server expose?
Substack by Cotlet exposes 67 tools: cotlet_whoami, cotlet_apps, cotlet_request_apps, cotlet_get_call, cotlet_upload_file, and 62 more. Their descriptions and schemas cost roughly 7,659 tokens of context every time the server is loaded.
Does the Substack by Cotlet MCP server require authentication?
No. We connected to Substack by Cotlet without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the Substack by Cotlet MCP server still maintained?
Substack by Cotlet is still listed as active in the MCP registry. We last reached this channel on 24 October 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.