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Svix MCP by usefulapi

io.usefulapi/svixusefulapi.iostreamable-httpv1.16.4Scanned

Send and debug webhooks — applications, endpoints, messages, delivery attempts and replays.

19 tools: 5 can delete or cancel things, 1 change things and 13 only read.

Tools: 5 delete, 0 irreversible, 1 write, 13 read.
  • Reads private data · 4
  • Reads text others write · 5
  • Can send data out · 2
  • No findings

Tools listed without sign-in. Remote posture

Anlyon alternative

6 of these tools change something. Run those as governed actions.

Declare what an action changes, and Anlyon puts it under a shared limit, binds every approval to the exact request, and grades the outcome. It works on any HTTPS API you can describe as an action.

Anlyon does not run, proxy or govern this MCP server. A tool your own code calls directly is not routed through Anlyon and is not governed by it.

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Tools

Grouped by what each tool does, most consequential first. Open one for its reasons and full description; descriptions are the publisher's own words.

19 tools

Deletes or cancels 5Claude Code: deny
  • svix_create_applicationCreate a new application (one tenant/customer of yours) in the Svix environment.No findings

    Why it is in this group

    • The name "svix_create_application" says "create": a word for a change.
    • The server marks it destructive (destructiveHint: true).
    Description, as the server wrote it
    Create a new application (one tenant/customer of yours) in the Svix environment. Svix REST: POST /api/v1/app.

    Annotations the server declares

    • title: Create an application
    • destructiveHint: true
  • svix_create_endpointRegister a webhook endpoint URL for one application, optionally scoped to specific event types and channels.No findings

    Why it is in this group

    • The name "svix_create_endpoint" says "create": a word for a change.
    • The server marks it destructive (destructiveHint: true).
    Description, as the server wrote it
    Register a webhook endpoint URL for one application, optionally scoped to specific event types and channels. Svix REST: POST /api/v1/app/{app_id}/endpoint.

    Annotations the server declares

    • title: Create an endpoint
    • destructiveHint: true
  • svix_recover_endpointReplay every failed message for one endpoint since a timestamp.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it destructive (destructiveHint: true).
    Description, as the server wrote it
    Replay every failed message for one endpoint since a timestamp. Runs as a background task — follow it with svix_list_background_tasks. Svix REST: POST /api/v1/app/{app_id}/endpoint/{endpoint_id}/recover.

    Annotations the server declares

    • title: Recover an endpoint's failed messages
    • destructiveHint: true
  • svix_resend_messageQueue one message for redelivery to one endpoint.Can send data outNo findings

    Why it is in this group

    • The name "svix_resend_message" says "resend": a word for sending, and what is sent cannot be taken back.
    • The server marks it destructive (destructiveHint: true).

    What it can reach

    • outboundThe name "svix_resend_message" says "resend": it sends or publishes something to other people.
    Description, as the server wrote it
    Queue one message for redelivery to one endpoint. The usual fix after a customer's endpoint was down. Svix REST: POST /api/v1/app/{app_id}/msg/{msg_id}/endpoint/{endpoint_id}/resend.

    Annotations the server declares

    • title: Resend a message to one endpoint
    • destructiveHint: true
  • svix_send_messageSend a webhook message to every endpoint of an application subscribed to the event type.Can send data outNo findings

    Why it is in this group

    • The name "svix_send_message" says "send": a word for sending, and what is sent cannot be taken back.
    • The server marks it destructive (destructiveHint: true).

    What it can reach

    • outboundThe name "svix_send_message" says "send": it sends or publishes something to other people.
    Description, as the server wrote it
    Send a webhook message to every endpoint of an application subscribed to the event type. This delivers real traffic to your customers' URLs. Svix REST: POST /api/v1/app/{app_id}/msg.

    Annotations the server declares

    • title: Send a message
    • destructiveHint: true
Changes things 1Claude Code: ask
  • svix_healthCheck that the Svix API is reachable and the API key works.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Check that the Svix API is reachable and the API key works. Returns 200 with an empty body when healthy. Svix REST: GET /api/v1/health.

    Annotations the server declares

    • title: Check API health
    • readOnlyHint: true
Only reads 13Show 13 read-only tools
  • svix_get_applicationFetch a single application by its Svix id or your own uid.No findings

    Why it is in this group

    • The name "svix_get_application" says "get": a word for reading.
    Description, as the server wrote it
    Fetch a single application by its Svix id or your own uid. Svix REST: GET /api/v1/app/{app_id}.

    Annotations the server declares

    • title: Get one application
    • readOnlyHint: true
  • svix_get_endpointFetch a single webhook endpoint, including its URL, subscribed event types and channels.Reads text others writeNo findings

    Why it is in this group

    • The name "svix_get_endpoint" says "get": a word for reading.

    What it can reach

    • untrusted-inputThe description's first sentence says "fetch" and "url": it reads web pages, which anyone can write.
    Description, as the server wrote it
    Fetch a single webhook endpoint, including its URL, subscribed event types and channels. Svix REST: GET /api/v1/app/{app_id}/endpoint/{endpoint_id}.

    Annotations the server declares

    • title: Get one endpoint
    • readOnlyHint: true
  • svix_get_endpoint_statsRead delivery statistics for one endpoint — counts of success, pending, sending and fail.No findings

    Why it is in this group

    • The name "svix_get_endpoint_stats" says "get": a word for reading.
    Description, as the server wrote it
    Read delivery statistics for one endpoint — counts of success, pending, sending and fail. The fastest way to see whether an endpoint is healthy. Svix REST: GET /api/v1/app/{app_id}/endpoint/{endpoint_id}/stats.

    Annotations the server declares

    • title: Get endpoint delivery stats
    • readOnlyHint: true
  • svix_get_event_typeFetch a single event type by name, including its description and JSON schema.No findings

    Why it is in this group

    • The name "svix_get_event_type" says "get": a word for reading.
    Description, as the server wrote it
    Fetch a single event type by name, including its description and JSON schema. Svix REST: GET /api/v1/event-type/{event_type_name}.

    Annotations the server declares

    • title: Get one event type
    • readOnlyHint: true
  • svix_get_messageFetch a single message, including its event type and payload.Reads private dataReads text others writeNo findings

    Why it is in this group

    • The name "svix_get_message" says "get": a word for reading.

    What it can reach

    • private-dataThe name "svix_get_message" says "get" and "message": it reads messages.
    • private-dataThe description's first sentence says "fetch" and "message": it reads messages.
    • untrusted-inputThe name "svix_get_message" says "get" and "message": it reads messages, which other people can write.
    • untrusted-inputThe description's first sentence says "fetch" and "message": it reads messages, which other people can write.
    Description, as the server wrote it
    Fetch a single message, including its event type and payload. Svix REST: GET /api/v1/app/{app_id}/msg/{msg_id}.

    Annotations the server declares

    • title: Get one message
    • readOnlyHint: true
  • svix_list_applicationsList the applications (your tenants/customers) in the Svix environment.No findings

    Why it is in this group

    • The name "svix_list_applications" says "list": a word for reading.
    Description, as the server wrote it
    List the applications (your tenants/customers) in the Svix environment. Svix REST: GET /api/v1/app.

    Annotations the server declares

    • title: List applications
    • readOnlyHint: true
  • svix_list_attempts_by_endpointList delivery attempts against one endpoint, newest first.No findings

    Why it is in this group

    • The name "svix_list_attempts_by_endpoint" says "list": a word for reading.
    Description, as the server wrote it
    List delivery attempts against one endpoint, newest first. Filter by status to find the failures. Svix REST: GET /api/v1/app/{app_id}/attempt/endpoint/{endpoint_id}.

    Annotations the server declares

    • title: List delivery attempts for an endpoint
    • readOnlyHint: true
  • svix_list_attempts_by_messageList every delivery attempt Svix made for one message, across endpoints — status, response code and body.Reads private dataReads text others writeNo findings

    Why it is in this group

    • The name "svix_list_attempts_by_message" says "list": a word for reading.

    What it can reach

    • private-dataThe name "svix_list_attempts_by_message" says "list" and "message": it reads messages.
    • private-dataThe description's first sentence says "list" and "message": it reads messages.
    • untrusted-inputThe name "svix_list_attempts_by_message" says "list" and "message": it reads messages, which other people can write.
    • untrusted-inputThe description's first sentence says "list" and "message": it reads messages, which other people can write.
    Description, as the server wrote it
    List every delivery attempt Svix made for one message, across endpoints — status, response code and body. This is the tool for answering 'why did this webhook not arrive?'. Svix REST: GET /api/v1/app/{app_id}/attempt/msg/{msg_id}.

    Annotations the server declares

    • title: List delivery attempts for a message
    • readOnlyHint: true
  • svix_list_background_tasksList Svix background tasks (bulk replays, expunges, imports) with their status.No findings

    Why it is in this group

    • The name "svix_list_background_tasks" says "list": a word for reading.
    Description, as the server wrote it
    List Svix background tasks (bulk replays, expunges, imports) with their status. Use it to follow up a recover or replay. Svix REST: GET /api/v1/background-task.

    Annotations the server declares

    • title: List background tasks
    • readOnlyHint: true
  • svix_list_endpoint_messagesList the messages destined for one endpoint, with each message's delivery status.Reads private dataReads text others writeNo findings

    Why it is in this group

    • The name "svix_list_endpoint_messages" says "list": a word for reading.

    What it can reach

    • private-dataThe name "svix_list_endpoint_messages" says "list" and "message": it reads messages.
    • private-dataThe description's first sentence says "list" and "message": it reads messages.
    • untrusted-inputThe name "svix_list_endpoint_messages" says "list" and "message": it reads messages, which other people can write.
    • untrusted-inputThe description's first sentence says "list" and "message": it reads messages, which other people can write.
    Description, as the server wrote it
    List the messages destined for one endpoint, with each message's delivery status. Svix REST: GET /api/v1/app/{app_id}/endpoint/{endpoint_id}/msg.

    Annotations the server declares

    • title: List messages for an endpoint
    • readOnlyHint: true
  • svix_list_endpointsList the webhook endpoints registered for one application.No findings

    Why it is in this group

    • The name "svix_list_endpoints" says "list": a word for reading.
    Description, as the server wrote it
    List the webhook endpoints registered for one application. Svix REST: GET /api/v1/app/{app_id}/endpoint.

    Annotations the server declares

    • title: List endpoints
    • readOnlyHint: true
  • svix_list_event_typesList the event types defined in the environment — the catalogue endpoints can subscribe to.No findings

    Why it is in this group

    • The name "svix_list_event_types" says "list": a word for reading.
    Description, as the server wrote it
    List the event types defined in the environment — the catalogue endpoints can subscribe to. Svix REST: GET /api/v1/event-type.

    Annotations the server declares

    • title: List event types
    • readOnlyHint: true
  • svix_list_messagesList the webhook messages sent for one application, newest first.Reads private dataReads text others writeNo findings

    Why it is in this group

    • The name "svix_list_messages" says "list": a word for reading.

    What it can reach

    • private-dataThe name "svix_list_messages" says "list" and "message": it reads messages.
    • private-dataThe description's first sentence says "list" and "message": it reads messages.
    • untrusted-inputThe name "svix_list_messages" says "list" and "message": it reads messages, which other people can write.
    • untrusted-inputThe description's first sentence says "list" and "message": it reads messages, which other people can write.
    Description, as the server wrote it
    List the webhook messages sent for one application, newest first. Filter by event type, channel, tag or time window. Svix REST: GET /api/v1/app/{app_id}/msg.

    Annotations the server declares

    • title: List messages
    • readOnlyHint: true

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Exfil surface

Which tools read private data, which read text someone else can write, and which can send data out. One of each is a path a prompt injection can use.

40 paths in this server alone from private data, through text someone else wrote, to a way out. Denying 2 outbound tools breaks every one.

Reads private data4
Reads files, mail, messages, databases, secrets, calendars or repositories.
Reads text others write5
Brings in text someone else can write: web pages, inbound email, messages, issues and comments.
Can send data out2
Can carry data to people or systems: it sends, posts or publishes, or takes a recipient, channel or URL.
deny to break every path
{
  "permissions": {
    "deny": [
      "mcp__svix__svix_resend_message",
      "mcp__svix__svix_send_message"
    ]
  }
}

Other servers in the same agent add their own tools to these paths. Audit your whole setup to see them together.

Remote posture

What anyone on the internet sees at the remote endpoint: an anonymous initialize and tools/list, and the public OAuth metadata.

Tools listed without sign-in

Looked at Oct 22, 2026, 15:31 UTC, unchanged since Oct 22, 2026. No credentials were sent and no tool was called. What is looked at.

Reachable
yes
HTTP status of an anonymous initialize
200
tools/list served without credentials
yes
Tools that change things, listed without credentials
6
Protocol version
2025-06-18
WWW-Authenticate on 401
not observed
resource_metadata in WWW-Authenticate
not observed
RFC 9728 protected resource metadata
https://svix.usefulapi.io/.well-known/oauth-protected-resource/mcp
Authorization servers
https://svix.usefulapi.io
Legacy HTTP+SSE transport
no
Dynamic client registration
yes
Client ID metadata documents
no
  • HighThe whole server

    The endpoint served tools/list without credentials, and the list has 6 tools that change things (5 destructive, 1 write). Whether a call also works without credentials was not tested: tools are never called.

    Matched text

    https://svix.usefulapi.io/mcp: tools/list returned 19 tools to an anonymous client, including svix_create_application (destructive), svix_create_endpoint (destructive), svix_send_message (destructive), svix_resend_message (destructive), svix_recover_endpoint (destructive) and 1 more

    What this check looks for

Findings

Matches of fixed checks, with the text they matched.

No check matched anything in these tool definitions. That is not a safety guarantee.

History

Changes to its tool definitions and to its remote endpoint, newest first.

No change seen yet. Its tools are rescanned every day, and a remote endpoint is looked at once a week.

All changes to this server

Install

Pinned to version 1.16.4. Values in angle brackets are yours to fill in.

claude mcp add --transport http svix https://svix.usefulapi.io/mcp
claude mcp add --transport http svix https://svix.usefulapi.io/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change or a way out, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__svix__svix_list_applications",
      "mcp__svix__svix_get_application",
      "mcp__svix__svix_list_endpoints",
      "mcp__svix__svix_get_endpoint",
      "mcp__svix__svix_get_endpoint_stats",
      "mcp__svix__svix_list_messages",
      "mcp__svix__svix_get_message",
      "mcp__svix__svix_list_attempts_by_message",
      "mcp__svix__svix_list_attempts_by_endpoint",
      "mcp__svix__svix_list_endpoint_messages",
      "mcp__svix__svix_list_event_types",
      "mcp__svix__svix_get_event_type",
      "mcp__svix__svix_list_background_tasks"
    ],
    "ask": [
      "mcp__svix__svix_health"
    ],
    "deny": [
      "mcp__svix__svix_create_application",
      "mcp__svix__svix_create_endpoint",
      "mcp__svix__svix_send_message",
      "mcp__svix__svix_resend_message",
      "mcp__svix__svix_recover_endpoint"
    ]
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. A read that can send data out (it takes a URL, say) asks first too. It assumes the server is installed as svix. Review it before you use it.

Capability tags behind 7 rules
  • mcp__svix__svix_get_endpoint untrusted-input
  • mcp__svix__svix_list_messages private-data, untrusted-input
  • mcp__svix__svix_get_message private-data, untrusted-input
  • mcp__svix__svix_list_attempts_by_message private-data, untrusted-input
  • mcp__svix__svix_list_endpoint_messages private-data, untrusted-input
  • mcp__svix__svix_send_message outbound
  • mcp__svix__svix_resend_message outbound

Pin

Keep the decision: fail CI when the tools change, follow every change, or show a badge.

Pin in CI

Fail a build when the tools you reviewed are not the tools the server serves today.

curl -s "https://anlyon.dev/api/v1/servers/io.usefulapi/svix/verify?hash=431f4733c8ab81e21a77ef74e0a47f2a58789a89234bf876e3166c22eaaf1a41" | jq -e '.changed == false'

Pinned hash 431f4733c8ab, from Oct 22, 2026, 11:20 UTC.

Watch

Get told when its tools change: a new tool, a new description, a new class.

https://anlyon.dev/servers/io.usefulapi/svix/changes.xml

An Atom feed. Works in any feed reader or Slack's RSS app.

Badge

anlyon.dev badge for io.usefulapi/svix
[![anlyon.dev](https://anlyon.dev/badge/io.usefulapi/svix.svg)](https://anlyon.dev/servers/io.usefulapi/svix)

Source: MCP Registry · repository. Synced Oct 22, 2026, 11:18 UTC.