Context engineering for your notes.
A local-first Markdown editor that structures your vault the way you structure context for your coding agent — plain .md files your AI can query like a database, not brute-force through.
Most Markdown editors are great for writing. They're terrible for agents.
Standard Markdown vaults confuse LLM agents. Tools like Claude Code or RepoAgent have to scan your entire directory from scratch — burning through context or pulling irrelevant files.
HermesMarkdown structures your vault so agents know exactly what to parse before they open a single file.
Agents scan before they read
HermesMarkdown automatically generates a lightweight AGENTS.md index. Agents parse this file first to filter by metadata (read_when, scope) without loading raw notes into the context window. Precise retrieval, zero wasted tokens.
- Automated detection of ambiguous cross-references or sprawling frontmatter
- Real-time structural score card (0–100) computed purely on-device
That index updates as you write — no separate step, no manual re-indexing. Scored across the four operations of context engineering: write, select, compress, isolate.
Write. Select. Compress. Isolate.
The four operations of context engineering — controlling what your agent sees on every call. HermesMarkdown builds each one into the vault itself.
Write
Every note lives in a plain .md file in your vault — not locked in a conversation, not lost when the context window rolls over.
Select
scope and read_when frontmatter tell your agent which files matter for a given task, before it reads a single word of body text.
Compress
Agents load your vault in three tiers — read_when, then scope, then full content — so they get just enough, not everything.
Isolate
WikiLinks make relationships between notes explicit. Agents follow a link instead of grepping your whole vault to guess what's related.
Start fresh or open what you already have
Open any existing local folder as a vault instantly — no migration, no conversion. Or create a new one from a starter pack: HermesMarkdown names the directory, writes the .hermes/ scaffolding, and drops you straight into a working vault. Four packs ship out of the box: empty slate, Notes/PKM, Engineering, and Personal Finance.
Every pack ships with frontmatter schema and an AGENTS.md index already in place — not just filled-in templates, but a vault that's agent-readable from the first file.
Nothing but the page, until you ask for more
Full-screen by default. A pinned icon rail on the left expands the file tree, search, and panels on demand — nothing else visible until you need it. Open files side by side, drag tabs between panes. Checkboxes toggle on click, dates open a calendar picker, Ctrl+Click any WikiLink to jump instantly.
Live formulas & keyboard-driven workflows
A keyboard-first table editor with native Excel-style formulas — =SUM(B), AVERAGE, IF — computed live in the editor. Tables on the same page can reference each other: =SUM(Income!B) pulls the total from a table named by its heading. Trigger slash commands anywhere to insert templates, calculate metrics, or format layouts instantly.
- #todo transitions dynamically to #prog and #done via native keyboard interaction
- Export tables to CSV — everything writes back to clean, auto-padded Markdown
You bring your own AI keys
Connect your Anthropic or Google Gemini API key. HermesMarkdown uses it to auto-generate scope fields, suggest related links, and improve your writing inline. Your keys stay in your browser — we never see them or proxy your requests.
No cloud. Your notes stay yours.
Built on a local-first philosophy. Your files reside exclusively on your machine in standard, human-readable Markdown — no account, no upload, no lock-in. Open any local directory as a vault, filter by tag or date, connect notes via WikiLinks. Opt-in Google Drive sync available for cross-device backups.
- Your notes and API keys never leave your device
- Complete ownership of your data and knowledge graph
Own your context. Own your output.
A Markdown editor structured for context engineering. Plain .md files. Runs in your browser, saves to your machine.