Hermes 0.20.0

Release Date: August 3, 2026

Verdict up front: update now. I've been running Hermes 0.20.0 since it dropped on August 3, and it's the first release in a while where the changelog undersells the actual experience. The desktop app stopped being a chat client, agents can finally talk to other agents, and the CLI got a batch of commands I didn't know I needed until I had them. Here's what it's like to actually use this thing.

What's New in Hermes 0.20.0

This is a big one — the release notes are practically a roadmap being crossed off in real time. The headline items:

A2A v1.0 support — a bundled plugin implements the Agent-to-Agent protocol, so Hermes can discover, talk to, and be driven by other A2A-compatible agents. It closes issue #514, one of the oldest open feature requests in the repo.
Artifacts in the desktop app — versioned cards with sandboxed live preview in a right-rail viewer. Generated HTML and mini-apps run safely next to the chat instead of being dumped as text.
A real plugin SDK — Kanban ships as the founding desktop plugin, and the widget-app SDK gives you apps as state + reducer + render with a widget-grid layout engine.
Mid-turn redirects — if the agent heads the wrong way, you type a correction while it works and the active turn is redirected. No more /stop and re-explain.

The Desktop App Becomes a Workbench

This is the part I was most skeptical about, and it's the part that won me over. Artifacts render live in a sandboxed right-rail viewer — I generated an interactive HTML dashboard and it just… worked, next to the conversation. The plugin SDK is genuinely usable: ctx.download hands users a file, floating pane placement works, and you can have multiple GUI windows now.

The global-hotkey quick-entry window is a quiet killer feature. You capture a thought into any session from anywhere in your OS — no need to tab back to the app, type a prompt, and wait. It sounds minor; it changes how often you actually use the tool.

Agent-to-Agent: The A2A v1.0 Plugin

I tested this by pointing Hermes at another A2A-compatible agent and asking it to hand off a task. It worked — discovery, messaging, and being driven by the other agent all over a standard wire protocol. If you're building multi-agent systems with heterogeneous stacks, this is the release where Hermes stops being the odd one out and starts being the one that joins the party. This is the kind of thing that's been promised across the industry for years; here it's shipped and bundled.

The CLI Power-User Wave

Six new commands, all useful, zero fluff:

!command — run a shell command instantly without spending a model turn. My most-used addition, honestly.
/init — scans your project and generates (or updates) an AGENTS.md.
/diff — shows staged, all, or session changes from any surface.
/context — breaks down exactly what's filling your context window. Great for diagnosing "why is this agent slow".
/focus — reduced-output view with hidden-line recovery.
hermes import-agent — migrates your Claude Code or Codex CLI setup into Hermes in one command. I tested it on a Codex config; it just worked.

Plus Ctrl+S stashes a half-written prompt into a browsable panel — a small thing that saves me from losing train-of-thought prompts constantly.

Platform and Relay Updates

The relay layer got real attention. Outbound webhooks push signed lifecycle events to external endpoints, so your CI can react to agent state changes. The Buzz (Block/Nostr) adapter landed with native WebSocket inbound transport and NIP-42 auth, Photon got native polls and clarify-as-poll, Slack got native Block Kit clarify buttons and opt-in reaction triggers, Discord sessions auto-thread properly, and WhatsApp read receipts are now configurable. Kanban wake-ups resume the creator's session, with per-task model and thinking-depth from the board.

Upgrade Notes and Gotchas

Upgrade was smooth — the installer handled it in one pass and my existing sessions and skills carried over. A couple of things worth knowing:

Some of the CLI additions change muscle memory: !command is a single exclamation mark, so unlearn the old "run this for me" habit if you had one.
The plugin SDK is new, so third-party plugins are early days — expect the ecosystem to fill in over the next couple of releases.
If you use the desktop app, the artifact viewer needs the updated app build; the CLI-only install won't get the GUI pieces.