# Hermes Agent v0.4.0: OpenAI-compatible API server, 6 messaging adapters, prompt caching

> Hermes gains an OpenAI-compatible `/v1/chat/completions` endpoint plus a jobs REST API, six new messaging platform adapters, and four new inference providers. Gateway prompt caching preserves the Anthropic cache across turns, and gateway approval moves from bare text to explicit `/approve` and `/deny` commands.

| | |
|---|---|
| **Tool** | Hermes Agent |
| **Version** | v2026.3.23 |
| **Kind** | release |
| **Published** | 2026-03-24 |
| **Observed** | 2026-08-11 |
| **Significance** | 4/5 |
| **Breaking** | yes |
| **Categories** | feature, api-change, breaking, capability, model-support, pricing |

## What changed


- OpenAI-compatible API server exposing `/v1/chat/completions`, plus `/api/jobs` REST API for cron management; hardened with input limits, field whitelists, SQLite response persistence, and CORS origin protection
- New adapters: Signal, DingTalk, SMS (Twilio), Mattermost, Matrix, Webhook — joining Telegram, Discord, WhatsApp; gateway auto-reconnects failed platforms with exponential backoff
- New inference providers: GitHub Copilot (OAuth + token validation), Alibaba Cloud/DashScope, Kilo Code, OpenCode Zen/Go
- `@file` and `@url` context references with CLI tab completion
- `hermes mcp` CLI for installing, configuring, and authenticating MCP servers over OAuth 2.1 PKCE
- Gateway prompt caching: AIAgent instances cached per session so the Anthropic prompt cache survives across turns, cutting cost on long conversations
- Context compression overhaul — structured summaries with iterative updates, token-budget tail protection, configurable summary endpoint, fallback model
- Behaviour change: CLI streaming is now on by default, with spinner and tool-progress display during streaming
- Behaviour change: gateway approval requires explicit `/approve` and `/deny` commands, replacing bare text approval
- New CLI commands: `/statusbar`, `/queue`, `/permission`, `/browser`, `/cost`
- 200+ bug fixes, including streaming chunk concatenation and linebreak handling, and spinner suppression in non-TTY environments


## Sources

- [github_release](https://github.com/NousResearch/hermes-agent/releases/tag/v2026.3.23) — retrieved 2026-08-11

## Community

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Canonical: https://changelogs.info/hermes-agent/v2026-3-23
Entity: https://changelogs.info/hermes-agent
Event ID: `evt_2026-03-24_hermes-agent_v2026-3-23`
Licence: event synthesis © changelogs.info, CC BY 4.0. Linked sources belong to their vendors.