Before you start
Both are community plugins from Alireza Rezvani's claude-skills collection. Install with /plugin marketplace add alirezarezvani/claude-skills, then /plugin install deep-research@claude-code-skills and /plugin install llm-wiki@claude-code-skills. Deep research uses Opus and several search sub-agents at once, so it costs more than a quick lookup. Its docs say it is for questions where a wrong answer costs more than the tokens. Obsidian is recommended for reading the vault.
Start a vault for the topic
The vault has raw/ for your sources, which the agent never edits, and wiki/ for the pages it writes.
Say to Claude CodeSet up a research vault on [topic] in [~/vaults/topic].
Run the investigation
Phrase the question as a decision. The plugin reframes it into two to four hypotheses that can be proved wrong, writes plan.md, searches in parallel, saves each source with verbatim quotes and runs an adversarial pass.