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PubNub Model Context Protocol MCP Server for Cursor and Claude
PubNub MCP server has significant definition quality gaps. Tool names lack consistent verb-noun structure (e.g., 'pubnub_subscribe_and_receive_messages' is verbose; 'pubnub_app_context' is vague). Descriptions are present but generic, most lack actionable context about when to use each tool vs. alternatives. Parameter schemas use Zod enums for some tools but lack comprehensive type definitions and validation rules. Output schemas are not documented. Error handling is minimal, no recovery guidance or categorization. The server mixes documentation tools (read_*) with operational tools (publish_*, signal_*) without clear separation. Tool composition is weak: 'pubnub_app_context' accepts a free-form 'operation' string instead of discrete, typed operations.
Retrieves message history from one or more PubNub channels.
Retrieves presence information for one or more PubNub channels.
Publishes a message to a PubNub channel.
Manages PubNub App Context (metadata) for users, channels, and memberships.
Subscribes to PubNub channels and receives messages in real-time.
Retrieves official PubNub Chat SDK documentation for a given programming language and topic. Returns documentation in markdown format.
Tool 'pubnub_app_context' accepts free-form 'operation' string instead of typed enum. LLM cannot infer valid operations without hallucinating values.
Tool names lack consistent verb-noun structure. 'pubnub_subscribe_and_receive_messages' violates single-responsibility (contains 'and'). 'pubnub_app_context' is vague, does it read, write, or both?
Output schemas are not documented. LLM cannot plan downstream tool calls or extract required fields (e.g., does get_pubnub_messages return message_id, channel, timestamp?).
| Scored | Grade | Overall | Spec posture | Rubric |
|---|---|---|---|---|
| 2026-09-23 | D | 55 | 2026-07-28+ | v2 |
Retrieves PubNub resource documentation including how-to guides, best practices, and conceptual information.
Retrieves official PubNub SDK documentation for a given programming language and API reference section. Call this tool for low-level API details, code examples, and usage patterns. Returns documentation in markdown format. For conceptual guides, best practices, and how-tos, also call the read_pubnub_resources tool.
Sends a signal message to a PubNub channel.
Provides instructions and scaffolding for writing a PubNub application.
Descriptions for 'read_pubnub_chat_sdk_docs' and 'read_pubnub_resources' are generic (40-50 chars). Missing guidance on when to call each vs. alternatives. No dependency hints.
No error handling guidance. Tools return generic errors without recovery hints. E.g., if publish fails, should LLM retry, check permissions, or verify channel exists?