---
title: "Agent harnesses need session search"
date: 2026-08-04
canonical: https://solmaz.io/x/2084521965239288185/
x_url: https://x.com/onusoz/status/2084521965239288185
license: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)
---

We are well into the agentic era, and the two big token harnesses Codex and Claude Code still do not give a search_session tool/CLI to agents by default?

For it to search back in its session for stuff that got lost after compaction?

Harnesses not produced by the big labs on the other hand might have this, like @AmpCode (read_thread, find_thread) and @goose_oss (Chatrecall)

Which could either mean...

a) Anthropic and OpenAI are being laggard
b) They are intentionally keeping the base harness simple, because it hasn't been requested by enough people
c) They have evidence that adding that complexity does not improve performance or even hurts it
d) They bet that compaction will be so good, that it won't be necessary

---

I don't believe (a) is true for either company

(b) and (c) are more likely, (c) especially if they noticed a tendency for the model to call search_session unnecessarily (though imo this can be solved by limiting the number of times that the model can call that)

(d) is logically false at the limit, but may be true in practice for >90% of the cases

It is false because LLMs compress lossily, and "lossy" by definition implies: there exists at least one case where the session gets so big, that the model will not be able to compress every relevant info into the allotted summary size

But I have seen that a considerable amount of people (including me or those at openai, see @reach_vb's quoted tweet) just keep using the same session for stuff. So a session being used for months straight will definitely not going to contain everything that happened in the summary

Just that fact alone necessitates search_session IMO, should the model learn to use it sparingly in the lossy edge cases
https://x.com/reach_vb/status/2068422255470579724

*Part 1/2 of a thread; root: https://solmaz.io/x/2084521965239288185/*
*Quotes a post by @reach_vb (https://x.com/reach_vb/status/2068422255470579724); its text is omitted here because it is not covered by this site's license.*