
A PhD student’s RETEX after two years with AI agents
Multiscale Modeling and Simulation Laboratory (MSME), Gustave Eiffel University, Champs-sur-Marne, France
2026-06-18

Why I became interested
2023 – internship with the Paris Fire Brigade
2024–today – regular use in my PhD work
literature code debugging writing slides

Too many papers
Find and compare faster
Implementation friction
Prototype and debug faster
A useful assistant?
Only with human judgement

An AI agent is like a very fast junior collaborator:
Useful for execution and exploration. Scientific originality and judgement remain my responsibility.
\[P(\text{token}_t \mid \text{tokens}_{<t})\]
It produces plausible continuations.
Useful? Very often.
True by default? No.

Hallucination and evaluation discussion: OpenAI (2025).
Chat

Question -> response
Agent

Goal -> tools -> actions -> results
My highest-value use is not “write code for me.”
It is: help me reach results I can check sooner.
Tool connections are standardized in part through MCP: Model Context Protocol (2026).
Interactive survey prepared for my previous seminar; pricing shown inside is a dated snapshot and should be verified before any decision.
Example: NotebookLM
Upload selected sources, then ask focused questions:
Where do two papers disagree?
Which assumptions define the method?
NotebookLM uses uploaded sources to answer requests: Google NotebookLM Help (2026).

An implementation is cheap. A validated result is valuable.
The clearer I am about the outcome, the less freedom the model has to invent the problem.
A serious prompt may be dozens or hundreds of lines.

Objective
Add a manufactured-solution convergence test for <equation/method>.
Context to read first
Read src/<operator>, test/<nearest existing test>, docs/MATH.md.
Scientific constraints
The exact solution is ... Evaluate L2 error at refinements [...].
Implementation contract
Start with a plan. Make the smallest patch. Run <command>.
Final response
List changed files, commands run, numerical results and uncertainty.Useful failures
Dangerous failures
The agent can run checks. I decide whether the result supports a scientific claim.
Example CLI commands
| Command | Use |
|---|---|
/init |
create project guidance |
/clear |
new independent topic |
/compact |
summarize context |
/rewind |
undo a bad direction |
/help |
discover commands |

Command examples originate from my Claude CLI notes; exact commands vary by tool.
Built-in features
CLAUDE.md loaded at start/skill)The same model, extended by your project context and tools.
Claude Code documentation: Anthropic Docs (2026).
Context window
An agent sees only the material provided or retrieved in the current working context.
Do not make it re-read the entire project for every question.
Search and formatting do not require the same reasoning budget as architecture or numerical diagnosis.
Persistent context
AGENTS.md / CLAUDE.md
build, test, conventions
MATH.md
equations and assumptions
SKILL.md
reusable Julia workflow

Files are versioned memory. Tests are executable memory.
AGENTS.md: operating manual for an agent
In CartesianGeometry.jl
integrate(...)
-> select backend
-> compute moments
-> return GeometricMoments
:vofi :voftools :implicitintegration
Validation encoded for the agent
Extracted from CartesianGeometry.jl/AGENTS.md, lines 1–17, 35–55 and 262–271.
MATH.md: scientific context that persistsCut-cell definition
\[V_C = \int_{C \cap \{\phi \le 0\}} dV\]
\[\mathbf{b}_C = \frac{1}{V_C} \int_{C \cap \{\phi \le 0\}} \mathbf{x}\,dV\]
Why give this to an agent?
Definitions from CartesianGeometry.jl/MATH.md, lines 7–44 and 119–157.
SKILL.md: Julia development rulesInstructions given to the agent
SArray for fixed collections.BenchmarkTools.jl before optimizing.Example Julia skill supplied for this talk; reusable Codex skills are documented in OpenAI (2026).
3 agents working in parallel on a single project:



Hosted US services
OpenAI, Anthropic, Google
Easy to access and powerful; material is processed through a provider service.
European alternative
Mistral AI
I tested Codestral, Devstral, and Mistral Studio.
Work nice for smaller tasks, but not yet a full replacement for hosted services.
Local open-weight model
More control, but:
Devstral local, reduced setup: run on a Mac M3 10 GPUs.
Before sending material
What leaves my machine?
May it be retained or trained on?
Who controls deployment and keys?
A relevant option
Mistral documents that API data is not used for model training and provides self-deployment routes for compatible models.
This does not replace checking project or partner rules.
AI agents do not replace research judgement.
They can free time for it.
Where could an agent remove friction in your work?
What tests or checks would make you trust its output?
What data must never leave your control?