Author profile

Lena Hartwell

Open Systems Lab, Germany

Records in AEX CONTINUUM (9)

PreprintsResearch ArticleNot peer reviewed

Mining Failure Modes from Agent Trajectories at Scale

Aisha Rahman, Lena Hartwell

Version 1 · 21 October 2026 · 10.xxxx/ctm.pp.2026.0007

Abstract PDF 2,065 6901 cited

PreprintsResearch ArticleNot peer reviewed

Prompt-Injection Resilience in Browser-Embedded Assistants

Marcus Tan, Sofia Lindqvist, Lena Hartwell

Version 1 · 2 October 2026 · 10.xxxx/ctm.pp.2026.0006

Abstract PDF 912 2880 cited

BooksMonograph

Evaluating Language Model Agents: Principles, metrics and practice

Lena Hartwell, Kofi Mensah

1st edition · 312 pages · ISBN 978-0-00-100001-2 · 30 September 2026 · 10.xxxx/ctm.bk.2026.0001

Read book PDF 5,240 2,8606 cited

ProceedingsFull paperBest paper

Retry Budgets for Tool-Using Agents: When Is Trying Again Worth It?

Aisha Rahman, Lena Hartwell

RTUA 2026 · pp. 1–9 · 3 July 2026 · 10.xxxx/ctm.pr.2026.0001

Abstract PDF 1,420 5602 cited

Research ArchiveSlides

Keynote Slides: Reliability Is a Measurement Problem

Version 1.0 · CC BY 4.0 · 13 June 2026 · 10.xxxx/ctm.ar.2026.0009

View record 520 2440 cited

Research ArchiveDataset

CTM-Bench: Task Set, Perturbations and Evaluation Harness

Marcus Tan, Kofi Mensah, Lena Hartwell

Version 1.2 · CC BY 4.0 · 12 June 2026 · 10.xxxx/ctm.ar.2026.0001

View record 3,860 2,2409 cited

PublishingReview ArticlePeer reviewed

A Survey of Evaluation Practices for Language-Model Agents: What is measured, how it is measured, and what is missing

Kofi Mensah, Ingrid Novak, Lena Hartwell

Version 2 · 4 reviewer reports · 22 May 2026 · 10.xxxx/ctm.pb.2026.0003

Abstract PDF 6,210 2,87011 cited

PublishingResearch ArticlePeer reviewed

Retrieval-Augmented Tool Selection for Long-Horizon Language Agents: Choosing from thousands of tools without placing them all in the prompt

Lena Hartwell, Tomás Ibarra, Marcus Tan

Version 2 · 4 reviewer reports · 27 February 2026 · 10.xxxx/ctm.pb.2026.0001

Abstract PDF 4,821 1,9367 cited

Research ArchiveSoftware

Tool-Selection Evaluation Harness

Lena Hartwell, Tomás Ibarra

Version 0.9.1 · MIT · 27 February 2026 · 10.xxxx/ctm.ar.2026.0002

View record 1,960 8843 cited