Plain.com MCP Server (tellahq/plain-mcp) is an MCP server listed on the M8ven Trust Index. It scores 56 out of 100, grade D. It declares 78 tools. No publisher has claimed this listing.
Provides comprehensive access to the Plain.com API with over 70 tools for managing support threads, customers, and help centers. It enables users to handle communications, automate support workflows, and manage documentation directly through natural language.
Caution. Specific findings reduced this grade. They are listed on the page. Grades reflect the full trust pyramid: code, verification depth, and reputation. New projects cap at C until adoption is earned.
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The grade above is for the source repository. Registries can serve a different version, so we mark the ones we were not able to read.
These names and descriptions are the publisher's own, read from the source code. We print them as written. Our assessment is the findings above, not this list.
list_help_centersList all help centers in the workspace
get_help_centerGet details of a specific help center
create_help_centerCreate a new help center
update_help_centerUpdate an existing help center
delete_help_centerDelete a help center
update_help_center_custom_domainSet a custom domain for a help center
verify_help_center_custom_domainVerify DNS ownership of a custom domain for a help center
list_help_center_articlesList articles in a help center
get_help_center_articleGet a specific help center article by ID
get_help_center_article_by_slugGet a help center article by its URL slug
upsert_help_center_articleCreate or update a help center article
delete_help_center_articleDelete a help center article
generate_help_center_articleAuto-generate a help center article from a support thread using AI
list_help_center_article_groupsList article groups (categories) in a help center
get_help_center_article_groupGet a specific article group by ID
create_help_center_article_groupCreate a new article group (category) in a help center
update_help_center_article_groupUpdate an article group
delete_help_center_article_groupDelete an article group
get_help_center_indexGet the navigation index/structure of a help center
update_help_center_indexUpdate the navigation index/structure of a help center
create_knowledge_sourceCreate a knowledge source for AI to reference
delete_knowledge_sourceDelete a knowledge source
upsert_customerCreate or update a customer
delete_customerDelete a customer
mark_customer_as_spamMark a customer as spam
unmark_customer_as_spamRemove spam marking from a customer
get_customerGet detailed customer information by ID
create_customer_eventCreate a custom event on a customer timeline
create_threadCreate a new support thread for a customer
assign_threadAssign a thread to a user
unassign_threadRemove assignment from a thread
change_thread_priorityChange the priority of a thread
update_thread_titleUpdate the title of a thread
delete_threadPermanently delete a thread
create_thread_eventCreate a custom event on a thread timeline
list_label_typesList all available label types
create_label_typeCreate a new label type
add_labels_to_threadAdd labels to a thread
remove_labels_from_threadRemove labels from a thread
upsert_companyCreate or update a company
delete_companyDelete a company
upsert_tenantCreate or update a tenant
delete_tenantDelete a tenant
list_snippetsList all snippets (canned responses)
create_snippetCreate a new snippet (canned response)
update_snippetUpdate an existing snippet
delete_snippetDelete a snippet
list_webhooksList all webhook targets
create_webhookCreate a new webhook target
update_webhookUpdate a webhook target
delete_webhookDelete a webhook target
list_usersList workspace users
get_workspaceGet current workspace information
send_emailSend a new email to a customer (starts a new thread)
send_chatSend a chat message to a customer
list_autorespondersList all autoresponders
create_autoresponderCreate a new autoresponder
delete_autoresponderDelete an autoresponder
list_tiersList all support tiers
create_tierCreate a new support tier
delete_tierDelete a support tier
list_customer_groupsList all customer groups
create_customer_groupCreate a new customer group
add_customer_to_groupsAdd a customer to one or more groups
remove_customer_from_groupsRemove a customer from one or more groups
list_thread_field_schemasList all custom thread field schemas
upsert_thread_fieldSet a custom field value on a thread
delete_noteDelete an internal note from a thread
list_threadsList support threads with optional filters. Note: statusDetail (CREATED, NEW_REPLY, etc.) is not available in list results - use get_thread for that.
get_threadGet detailed thread information including conversation timeline
search_customersSearch for customers by email
get_queue_statsGet a quick overview of the support queue with counts by status
reply_to_threadReply to a support thread. The reply will be sent to the customer via the original channel (email, chat, etc.)
mark_thread_doneMark a support thread as done/resolved
mark_thread_todoMark a support thread as todo (re-open it)
change_thread_status_to_todoChange thread status to Todo with optional status detail. Use this instead of mark_thread_todo when you need to set a specific status detail.
snooze_threadSnooze a support thread. Use WAITING_FOR_CUSTOMER (no duration) to snooze until customer replies, or WAITING_FOR_DURATION with duration_seconds for time-based snooze.
create_noteCreate an internal note on a thread (not visible to customer)
Disclosed vulnerabilities in this server's declared npm dependencies (via OSV). Whether each is reachable depends on the installed versions.
@modelcontextprotocol/sdk has cross-client data leak via shared server/transport instance reuse
Anthropic's MCP TypeScript SDK has a ReDoS vulnerability
Model Context Protocol (MCP) TypeScript SDK does not enable DNS rebinding protection by default
PLAIN_API_KEY"": "your-api-key"Tool annotations
No tools have read-only/destructive annotations
Add readOnlyHint or destructiveHint annotations to every tool so hosts can warn users before invoking.
All four hints declared on every tool
78/78 tools missing one or more hints — list_help_centers (missing: readOnlyHint, destructiveHint, idempotentHint, openWorldHint); get_help_center (missing: readOnlyHint, destructiveHint, idempotentHint, openWorldHint); create_help_center (missing: readOnlyHint, destructiveHint, idempotentHint, openWorldHint), +75 more. OpenAI's directory rejects tools where any of the four hints are missing or non-boolean.
For every tool, set all four hints (readOnlyHint, destructiveHint, idempotentHint, openWorldHint) to explicit true/false values that match the handler’s actual behaviour.
Tool inputs are validated
70/78 tool handlers declare input schemas (90%)
Declare an inputSchema with zod/joi/yup on every tool definition.
Tool handlers catch errors
Only 0/78 tool handlers wrap calls in try/catch (0%)
Wrap each tool handler body in try/catch and return a structured error response.
License file
No license file
Add a LICENSE file (MIT, Apache-2.0, etc.).
Tests exist
No test files found
Add tests that exercise each declared tool.
Production dependencies are patched
0 critical, 3 high severity in production deps — @modelcontextprotocol/sdk@1.23.0 (high), @modelcontextprotocol/sdk@1.23.0 (high)
Run npm audit fix, or upgrade the affected packages to a non-vulnerable version.
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[](https://m8ven.ai/mcp/tellahq/plain-mcp)?variant=verified from the URL.Vetting this one by hand? Tool Check is an MCP that scores other MCPs. Add it once and ask Claude, ChatGPT, or any MCP client to grade a server, surface CVEs, check the publisher, and suggest safer alternatives — before you install.
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