Mellum by JetBrains

A harness is the runtime wrapper that turns a bare language model into an agent — the layer that runs tools, holds memory, assembles context, and enforces limits. The model does the reasoning; the harness does everything the model can't do on its own. It's the part that decides whether you shipped a chatbot or a real agent — and it's why the same model feels brilliant in one tool and useless in another.

Claude Code has built-in memory — a CLAUDE.md file it reads each session — but it only holds short, hand-written notes. To make it understand a large codebase or docs set, you add a second brain: turn the repo into a knowledge graph, fold that into an Obsidian vault, and let the agent query the map instead of re-reading every file.

Claude Code can do most of your SEO — build a crawlable static site, write and optimize pages, fix the technical layer, even bottle the whole workflow into a reusable skill. What it can't do is invent authority or pick keywords, and if you let it generate 10,000 pages you'll get de-indexed, not ranked. Here's the honest, hands-on version for a maker whose site shipped last week.