APPENDIX A: GLOSSARY OF TERMS AND ACRONYMS

TERMS BEGINNING WITH H Hallucination: when a model states something false with confidence, such as a made-up fact or source. Handler: the piece of code that actually carries out a tool when it is called. Handoff: fully passing control of a task from one agent to another. Handoff document: a written guide that lets a new person take over a component. Handoff note: a note written at the end of one session to start the next. Handoff object: a small, structured package of the facts the next agent needs, used instead of passing along the whole history. Hands-on competency: a skill you must demonstrate by doing. Harness: the software around a model that runs tools, manages memory and context, handles errors, and keeps the agent inside safe limits. Harness engineer: a person who builds the dependable system around a model. Harness engineering: the discipline of designing everything around a model so that an agent works reliably in the real world. Hash: a fingerprint of a file used to confirm integrity. Held-out set: a hidden test set not used for tuning. Heuristic: a practical rule of thumb that usually works but is not guaranteed to be right. Holistic leaderboard: one that judges across many scenarios and measures. Honest capability claim: a description that stays true on the system's worst day. Hook: code that runs automatically at a defined moment in an agent's work. Host, client, server: the application, its connection piece, and the program offering capabilities. Hosted model: a model that runs on a provider's computers and that you reach over the internet. Hot tier: the active context window. HTTPS: the short form of Hypertext Transfer Protocol Secure (HTTPS). Human evaluation: having real people judge the quality of an agent's output. Human-in-the-loop: a design in which a person must review or approve certain steps before the system continues. Hybrid search: combining meaning search and keyword search. Hypertext Transfer Protocol Secure (HTTPS): the standard way web traffic is sent with encryption so others cannot read it along the way.