Hermes Agent Demystified — Why AI Twitter Won't Shut Up About It
Breaking down Hermes Agent from Nous Research — what skills, GEPA, and self-improving workflows actually mean under the hood. No hype, just how it works.
I kept seeing Hermes Agent from Nous Research pop up everywhere — Twitter threads, Discord channels, YouTube breakdowns. Everyone calling it "the self-improving AI agent."
My first reaction? "Cool, another coding agent. We already have Claude Code, Cursor, Codex, OpenHands..."
But then I actually read through their repo and documentation. And okay — there's something genuinely interesting here. Not magic. Not AGI. But a clever idea that most people are either overhyping or completely misunderstanding.
Let me break it down the way I understand it.
What Hermes Actually Does
At its core, Hermes is an AI agent that can use tools, read files, execute commands, browse websites, and complete tasks.
Nothing new so far. Claude Code does this. Cursor does this. Codex does this.
The interesting part — Hermes tries to improve itself over time.
Instead of completing a task and forgetting everything, Hermes attempts to learn reusable workflows it calls "skills." That word matters. Not "fine-tuning." Not "training." Skills.
How Every Other Agent Works
Here's the typical agent loop:
User gives task → Agent executes → Task done → Everything forgotten.
Next time you ask something similar? Starts from zero. No memory of what worked before, what failed, what was efficient.
Every single time — blank slate.
How Hermes Changes This
Hermes adds a reflection step after execution:
User gives task → Agent executes → Agent reflects on what happened → Creates or updates a skill → Stores it → Uses it automatically next time.
Real example — you ask Hermes to review a GitHub pull request. After finishing, it realizes this workflow worked well:
- Read changed files
- Check security issues
- Check performance concerns
- Check coding standards
- Generate review comments
Hermes saves this as a reusable skill. Next PR review request? It loads that skill instead of figuring everything out from scratch.
What a "Skill" Actually Is
This is where people get confused. They hear "skill" and imagine some trained neural network module.
Nope.
A skill is usually just a structured markdown file. Instructions, best practices, examples, workflows, tool usage patterns — organized into a reusable playbook.
That's it. A markdown file.
# GitHub Review Skill
1. Read changed files
2. Check security vulnerabilities
3. Check performance impact
4. Generate review summary
5. Prioritize critical findings
If you've ever written a CLAUDE.md file or a system prompt — congratulations, you've basically written a skill.
The Retrieval Problem — 500 Skills, Limited Context
Now imagine Hermes accumulates 500 skills over time. It can't load all of them into context every time — that would blow up the token count.
So it does something similar to RAG (Retrieval-Augmented Generation):
New task comes in → Semantic search across skill library → Load top matching skills → Execute with those skills in context.
For a GitHub review request, it might pull in:
- Code Review Skill
- Security Review Skill
- Git Analysis Skill
Only what's relevant gets injected. Everything else stays in storage.
This is clean engineering — not magic.
GEPA — The Part That Actually Generates Hype
GEPA stands for Genetic-Pareto Prompt Evolution.
Sounds intimidating. The idea is surprisingly simple.
Traditional AI improvement: Collect data → Train model → Spend thousands on GPUs → Deploy.
GEPA improvement: Collect execution traces → Find where agent failed → Create improved skill variations → Test them → Keep the winner.
No model training. No GPU costs. Just better instructions.
How GEPA Works — A Real Example
Say Hermes has this skill:
"Review code and provide feedback."
GEPA notices the agent keeps missing security vulnerabilities in reviews. So it creates variations:
- Version A: "Review security before code style."
- Version B: "Check authentication and authorization first."
- Version C: "Run OWASP security checks before quality checks."
All three get tested against real tasks. The version that catches the most real bugs survives. The rest get discarded.
This is literally natural selection applied to prompts. The strong instructions survive. The weak ones die.
Why "Genetic" Evolution?
Because it follows the same pattern:
Original skill → Create mutations → Test fitness → Keep survivors → Repeat.
Instead of DNA, the genetic material is prompt text. Instead of environmental pressure, the selection pressure is task success rate.
It's not a metaphor — it's genuinely the same algorithm biologists describe, applied to text instead of organisms.
What's Under the Hood
When people hear "self-improving AI," their brain jumps to AGI, Skynet, recursive self-improvement spirals.
The reality is boring — in the best possible way.
Hermes is built from:
- LLM — the reasoning engine (could be any model)
- Memory — persistent storage across sessions
- Tool calling — file I/O, shell commands, web browsing
- Skill files — markdown playbooks
- Semantic search — RAG over skill library
- Reflection — post-task analysis
- GEPA — evolutionary optimization of skills
The core loop: Task → Tools → Memory → Skill Retrieval → Execution → Reflection → Skill Improvement.
That's the whole system. No hidden neural network training. No gradient descent. No weight updates.
My Honest Take — Is This Revolutionary?
Partly.
Tool usage? Not new. Claude Code, Cursor, Codex, OpenHands — all do this already.
Memory and skills? Claude Code has CLAUDE.md files and memory banks. Cursor has .cursorrules. These are manually created skills.
The genuinely new part is automated skill improvement without human intervention. Instead of an engineer manually rewriting prompts when something fails, Hermes tries to do it itself through GEPA.
That's the real innovation — not any single component, but the automated feedback loop connecting them.
The Uncomfortable Truth
Here's what nobody in the hype threads wants to admit:
Most AI agents today — including the ones you're paying $20-200/month for — are built from markdown files, prompt templates, vector search, memory, and tool calling.
Hermes isn't magic. It's a very clever combination of existing components.
But that feedback loop — the part where skills evolve automatically based on real execution data — that's genuinely interesting engineering. It's the difference between a static playbook and one that rewrites itself based on what actually works.
One Line Summary
Hermes Agent = LLM + Memory + Automatic Skill Creation + GEPA-based Workflow Evolution.
It doesn't become smarter by changing neural network weights. It becomes more effective by improving its own operating manual — automatically.
Think of it as an AI employee that writes, tests, and improves its own SOPs. That's it. That's the whole idea.
And honestly? That simple idea might be more useful than most of the "revolutionary AI" launches I see every week.
The Hermes Agent repo is public if you want to dig deeper: github.com/nousresearch/hermes-agent
If you want all my research documents on harness engineering, agent architectures, and GEPA — just mail me. I'll share everything.