AI tool comparison
Metrics SQL by Rill vs Mnemos
Which one should you ship with? Here is the side-by-side panel verdict, pricing read, reviewer split, and community vote comparison.
Developer Tools
Metrics SQL by Rill
One SQL semantic layer so AI agents stop hallucinating your KPIs
75%
Panel ship
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Community
Paid
Entry
Metrics SQL is a SQL-based semantic layer from Rill Data that solves a specific and painful problem: AI agents that query your data warehouse tend to hallucinate aggregation logic, producing metrics that look plausible but are mathematically wrong. Metrics SQL lets analysts define business metrics once — revenue, MAU, conversion rate, ROAS — in a governed definition layer, and then exposes those definitions as queryable SQL tables. Every dashboard, notebook, and AI agent resolves from the same source. The technical approach is elegant: rather than inventing a new DSL, Metrics SQL extends SQL itself. An agent that knows SQL can query `SELECT * FROM metrics.weekly_revenue` and get correctly computed numbers without needing to know how revenue is defined, which tables it joins, or how edge cases like refunds are handled. The semantic layer intercepts the query, applies the governed definition, and returns correct results. The implications for AI-native data stacks are significant. Currently, one of the biggest failure modes for AI analysts and BI agents is inconsistent metric computation — different agents or dashboards produce different numbers for 'revenue' because they implement aggregation logic differently. Metrics SQL addresses this at the infrastructure level, not by improving agent prompting.
Developer Tools
Mnemos
Local vector memory for Claude Desktop with 3D conversation visualization
75%
Panel ship
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Community
Free
Entry
Claude Desktop has no memory across sessions. You close the window and it forgets everything. Mnemos is an open-source MCP server that fixes this by watching your conversation files in real-time, indexing them with local ONNX embeddings (MiniLM-L6-v2), and enabling hybrid semantic + keyword search — all without a single byte leaving your machine. The v1.1 release adds a genuinely striking feature: a 3D semantic visualization that maps your conversations into a clustered constellation using UMAP dimensionality reduction and Three.js. You can scrub through a chronological timeline and watch the knowledge graph build in real time. It is, frankly, prettier than it needs to be. Built on .NET 9, SQLite FTS5, and React/Vite, Mnemos is one of the more technically ambitious "Claude memory" projects to appear on HN this week. The offline-first, MIT-licensed approach puts it in a different league from cloud-synced alternatives.
Reviewer scorecard
“We've been burned by data agents that invent their own GROUP BY logic and produce wrong numbers that look right. Metrics SQL solves this at the infrastructure level — define revenue once, have every agent query the same definition. The SQL-native interface means no new tools for agents to learn; they just use the tables.”
“This solves a real, painful problem with zero cloud dependency. The hybrid FTS5 + vector search is the right architecture — you get speed and semantic richness without compromising privacy. The .NET 9 stack is slightly niche but the setup looks smooth.”
“The value here is only as good as how well-maintained your metric definitions are — if analysts don't keep them updated, agents query stale or wrong definitions and you've added a layer of false confidence. Adopting a semantic layer also creates vendor dependency; migrating away from Rill's cloud later is a real switching cost. For smaller teams without dedicated data engineering, maintaining a semantic layer is overhead.”
“It is a one-person Show HN project posted literally today with 2 GitHub stars. The 3D visualization is cool but has nothing to do with actually improving recall quality. Also: how often do you actually need to search old Claude conversations vs. just starting fresh?”
“Data governance and AI agents are on a collision course. As more business decisions are delegated to AI, the correctness of KPI computation becomes load-bearing — a hallucinated revenue figure that influences a product decision is a serious failure mode. Metrics SQL represents a class of infrastructure that will become mandatory as AI takes on more analytical work.”
“Local-first AI memory is the correct long-term architecture. Every AI system we rely on should have this kind of persistent, private, searchable context layer. Mnemos is a prototype of what OS-level AI memory will eventually look like, and seeing it built today matters.”
“I rely on AI to pull weekly performance data, and the number of times it's given me different 'correct' answers for the same metric is maddening. Having a single governed source that every AI query resolves against means I can trust the numbers I'm making decisions on. That trust is worth a lot.”
“The 3D constellation visualization genuinely excites me — there is art in watching your conversation history render as a navigable space. For writers and researchers who use Claude heavily, the ability to rediscover old threads through semantic search could unlock something meaningful.”
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