last: omp (Oh My Pi) panes fall back to the screen; Herdr already provides the exact transcript path

[jonathannd02]

Summary

plannotator-tui last cannot resolve transcripts for omp ("Oh My Pi") panes. omp is not in the supported host list, so herdr last (and therefore Herdr Annotate's annotate.last / prefix+shift+o) takes the unsupported-host fallback and shows the pane's recent screen output instead of the agent's last reply.

The interesting part: Herdr already hands you the exact transcript path for these panes, and your existing reader already parses the format correctly. So this can be a very small fix.

Environment

• plannotator-tui 0.3.0, as bundled by herdr-annotate 0.3.0 (commit 8dc0de1)
• Herdr 0.8.2; reproduced on macOS arm64 and Linux x86_64
• Agent: omp; Herdr integration omp reports current (v8)

What happens

herdr last resolves the pane and opens the doc pane with only a host name and a pid (captured by wrapping HERDR_BIN_PATH with a logging stub):

CALL: pane process-info --pane <pane>
CALL: plugin pane open --plugin plannotator-tui --entrypoint doc --placement overlay --focus
        --env PLANNOTATOR_TUI_HOST=omp
        --env PLANNOTATOR_TUI_MESSAGE_PID=<pid>
        --env PLANNOTATOR_TUI_DELIVER_TO=<pane>

omp is not among claude, codex, copilot, droid, pi, so it hits the documented path
… is not supported yet; supported hosts: … → — showing the pane's recent output instead,
with the header reading <agent> · screen rather than <agent> · last message.

Same pane, same moment, comparing the resolution the doc pane performs against the correct answer:

invocation	result
last --host omp --pid <pid> --print	1537 bytes; an assistant message that is not the newest
last --session <transcript> --print	3893 bytes; the actual newest assistant reply

--pick 0, --pick 1 and --pick 2 all return the same 1537 bytes, so this is not an index off-by-one.

Expected

last on an omp pane shows that pane's newest assistant reply, with the header omp · last message.

Why this should be cheap

1. Herdr resolves the transcript per pane, and it is a path. For omp panes the ref kind is path, so no discovery is needed at all:

$ herdr agent get <pane>
{"agent":"omp",
 "agent_session":{"agent":"omp","kind":"path","source":"herdr:omp",
                  "value":"~/.omp/agent/sessions/<mangled-cwd>/<ISO8601>Z_<uuidv7>.jsonl"}}

herdr api schema defines AgentSessionRefKind as ["id", "path"] and AgentSessionInfo as {source, agent, kind, value} (all required). The string agent_session does not occur anywhere in the shipped 0.3.0 binary, so this field appears to be unused today.

2. The format already parses. last --session <that path> --print returns exactly the right reply. Only discovery is missing, not parsing.

3. The on-disk layout matches your own pi fixtures. omp writes:

~/.omp/agent/sessions/<mangled-cwd>/<ISO8601>Z_<uuidv7>.jsonl

Compare crates/plannotator-tui-hosts/tests/fixtures/pi-sessions/--work-project--/2026-08-28T10-00-00-000Z_01a00000-0000-7000-8000-000000000001.jsonl — same mangled-cwd directory, same <timestamp>_<uuidv7>.jsonl naming. Record types are {"type":"message","role":"assistant"|"user"|"toolResult"} alongside session, title, model_change and custom records.

4. Env-based discovery cannot work here. An omp pane exports only HERDR_BIN_PATH, HERDR_ENV, HERDR_PANE_ID, HERDR_SOCKET_PATH, HERDR_STARTUP_CWD, HERDR_TAB_ID, HERDR_WORKSPACE_ID. There is no PI_CODING_AGENT_SESSION_DIR, no PI_CODING_AGENT_DIR, and no OMP_* equivalent, so the pi reader's env probes find nothing even if omp were aliased to it. Under Herdr, agent_session is the only reliable source.

Suggested fix

Either of these solves it; the first is narrow, the second fixes a whole class:

1. Add crates/plannotator-tui-hosts/src/omp.rs with root ~/.omp/agent/sessions (or alias omp onto pi.rs with a second root), plus a fixture mirroring pi-sessions/.
2. When HERDR_ENV=1, prefer Herdr's agent_session over host+pid discovery: on kind: "path", read value directly and skip the host table entirely.

Option 2 would also cover the other agents Herdr integrates but plannotator-tui does not — herdr integration status lists 17 agent integrations against your 5 hosts.

Happy to test a patch against a real omp setup.

[backnotprop]

Confirmed, thanks for the exact trace. Going with your option 2 first: herdr last now reads herdr agent get and forwards agent_session to the pane (PR #26), so a kind: path session is opened directly. An omp host (pi's format under ~/.omp/agent) and format sniffing for unknown hosts follow in the next PR; then 0.3.1 and a pin bump in herdr-annotate. I'll ping you here to verify on a real omp pane.

[backnotprop]

Shipped in plannotator-tui 0.3.1, pinned by herdr-annotate on main (c63dfc9): herdr last now forwards Herdr's agent_session to the pane, so an omp pane opens the exact transcript Herdr reports; there is also an omp host (pi's format under ~/.omp/agent) and format sniffing for any session path without a known host. Reinstall to pick it up: herdr plugin install plannotator/herdr-annotate. Could you confirm on your omp pane that the header reads omp · last message and the newest reply is the one shown? I'll close on your word.

[backnotprop]

Closing as shipped in 0.3.1 (herdr-annotate main pins it). Verified against the oh-my-pi source: sessions under ~/.omp/agent, OMPCODE marker, and Herdr's agent_session path opened directly. Reopen with a trace if an omp pane still shows the screen fallback.