"Signal" matching MCP servers:

Enables AI agents to capture URLs and files, search and triage the inbox/library, read and chat with sources, and manage topics through MCP.

The most complete Signal MCP server and CLI.

Local-first inspectable memory substrate for Claude Code. Three read-only MCP tools (search_pairs, compact_session, substrate_info) over a signal-scored parse of ~/.claude/projects/, zero outbound calls.

Structured knowledge API for AI agents — fractal knowledge graphs, signal datasets, authority evidence reviews, open problems, and capability specs. Pay-per-query or subscription via Lightning, Stripe, or USDC.

A local-first persistent memory server that provides AI agents with deterministic, multimodal information retrieval across different sessions and projects. It enables long-term memory continuity using a 5-signal hybrid search engine and cognitive reasoning loops designed for complex development workflows.

Provides long-term memory for AI agents through time-decay validity scoring, so stored facts, notes, and entities are automatically forgotten or flagged as stale instead of being recalled forever. Enables logging high-signal memories, searching them with freshness guidance, extracting daily timelines, and maintaining long-lived entity references across sessions.

This MCP server enables AI agents to extract, verify, and cache factual claims from text using Claude Haiku and semantic fingerprinting, with tools for content verification, signal verification, and fact memory search.

A read-only MCP server that interprets cat behavior signals with evidence and context, helping users understand their cat's actions.

Provides shared long-term memory and proactive suggestions across AI coding agents, enabling persistent user preferences and behavior rules that are remembered and applied across different tools. Includes memory capture, recall, extraction, and suggestion tools with a local-first and privacy-focused design.