Resuming the session you had yesterday
find it across every agent, then reopen it in the right one
Every agent can resume its own last session. None of them can tell you which session you want, and none of them can see the one you had in a different tool — which is where the answer usually is.
Find it first
deja "connection pool exhausted"
Search runs over every agent's transcripts on the machine at once, and each hit carries the harness it belongs to and its session id. That is the step the tools themselves cannot do: claude --resume lists Claude's sessions, codex resume lists Codex's, and neither knows the other exists.
Then reopen it
deja resume <id>
It prints the command that reopens that exact conversation, including the directory it has to run in when the tool scopes its session list by working directory:
cd '/path/to/project' && grok --resume 01a03433-0c67-7331-8eb1-cd6173d4c8f9
Sixteen of the twenty harnesses deja indexes can be reopened this way. The other four are refusals with a reason rather than silence: aider appends to a transcript file and has no notion of reopening one conversation, Roo and Zed reopen from their own UI rather than a terminal, and neither of DeepSeek Harness's two apps takes a session id. The format registry records which is which, and why.
When resuming is the wrong tool
Reopening a session brings back the whole conversation, including the parts that were wrong before they were right. Often what you want is the conclusion, not the road to it:
deja ctx <id-prefix>
That returns the session as a digest — what was decided, which files it touched, which commands ran — small enough to paste into a session you are already in. Finding a session covers the search side in more detail.
The part that is not about this
The index covers every agent's transcripts on the machine — each in its own format — including sessions from before deja was installed. Indexing and search are local: BM25 over the transcripts, credentials stripped as the index is built (privacy).