fix(pi-plugin): support pi-web multi-session and RPC hosts

[elrond298]

Summary

This PR adapts the Pi plugin for pi-web, where multiple Pi sessions share one persistent Node.js process and commands run through Pi’s RPC mode.

It addresses shared-process session isolation, duplicate startup work, unsafe subagent CLI detection, RPC command feedback, and /ctx-dream failures before the first model turn.

Changes

Session isolation

• Replace the process-global child-session flag with an AsyncLocalStorage<boolean> marker.
• Update the marker through the public subagents:child:session-created and subagents:child:disposed events.
• Suppress initialization only for in-process child subagents.
• Allow independent sessions in the same pi-web process to initialize normally.
• Remove child lifecycle listeners during session_shutdown to prevent stale handlers after reloads.

Process-wide startup maintenance

• Claim deferred startup maintenance once per process.
• Schedule the legacy-memory identity rekey introduced by database migration v22 only once per process.
• Schedule the session-to-project mapping backfill only once per process.
• Load session history only after acquiring the durable backfill lease, avoiding redundant JSONL scans.

Safer subagent CLI detection

• Reuse process.argv[1] only when it identifies a supported Pi CLI; otherwise use the packaged executable, bundled CLI, or PATH fallback as appropriate.
• This prevents embedded hosts such as Next.js from accidentally launching another web server when creating a subagent.

RPC command presentation

• Preserve model-invisible command entries while presenting them through the RPC UI.
• Show short progress updates through ctx.ui.notify.
• Show formatted results in modal dialogs through ctx.ui.custom.
• Apply this behavior to /ctx-status, /ctx-embed, /ctx-recomp, /ctx-session-upgrade, and /ctx-dream.

Dreamer registration

• Track Dreamer registration ownership per Pi extension instance.
• Prevent one session’s shutdown from deregistering a same-project sibling.
• Transfer the active registration to a remaining worktree owner when necessary.
• Synchronize the current project’s Dreamer registration immediately before a manual /ctx-dream run.
• This allows /ctx-dream to work before the first before_agent_start event.

Verification

• bun run --cwd packages/pi-plugin build
• bun run --cwd packages/pi-plugin test — 804 passed, 0 failed
• bun test packages/plugin/src/features/magic-context/session-project-backfill.test.ts — 9 passed, 0 failed
• git diff --check

Regression coverage includes:

• independent same-process sessions versus child-session suppression
• lifecycle listener cleanup during shutdown
• process-wide startup maintenance claimed through full runtime initialization
• lazy backfill lease gating without session-history reads
• owner-aware Dreamer registration, shutdown isolation, and ownership transfer
• single-timer Dreamer handoff when remaining owners repeat a worktree directory
• embedded-host Pi CLI discrimination
• RPC notification and modal-dialog routing
• pre-execution /ctx-dream registration synchronization

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Summary by cubic

Supports pi-web multi-session and RPC hosts in packages/pi-plugin and isolates work by session and owner. Old behavior suppressed all same‑process inits and drained all jobs on shutdown; new behavior suppresses only in‑process child subagents, drains only the shutting‑down session’s historian/recomp and the active owner’s Dreamer jobs, and presents command output through the live RPC context.

• Scope child-session detection to lifecycle AsyncLocalStorage; remove lifecycle listeners on session_shutdown; keep agent_end synchronous.
• Claim process‑wide startup tasks once and defer session‑history reads until the backfill lease is acquired.
• Dreamer registration is shared per project and owner-aware: require an active registration owner for manual runs, ensure registration before /ctx-dream, resolve manual runs through the active owner’s options, reject ownerless/deregistered requests, transfer/handoff ownership on exit, notify all owners after adjunct updates, preserve process‑shared argument order across extension reloads, prevent stale runs across worktrees, and track complete manual runs (including lease waits) during shutdown.
• Route command output through the live RPC context: short progress via ctx.ui.notify; detailed results or rpcDisplay: "dialog" via ctx.ui.custom. Applied to /ctx-status, /ctx-embed, /ctx-recomp, /ctx-session-upgrade, /ctx-wrapup, /ctx-flush, and /ctx-dream.
• Await only the matching session’s historian and recomp during session_shutdown; drain only the active owner’s in‑flight Dreamer work with timeouts.
• Resolve subagent CLI safely: reuse process.argv[1] only when the host is the Pi CLI; otherwise prefer the packaged binary, bundled CLI, or pi on PATH. Never spawn with a shell.

^{Written for commit abc835f. Summary will update on new commits.}

Greptile Summary

This PR adapts the Pi plugin to persistent, multi-session RPC hosts while isolating session lifecycle state and process-wide maintenance.

• Uses async-context child-session detection instead of a process-global active-session latch.
• Coordinates Dreamer registration and shutdown through per-instance ownership.
• Scopes historian and recomp draining by session.
• Routes command progress and detailed results through each live RPC context.
• Hardens subagent CLI selection for embedded hosts.
• Defers session-history scans until the durable backfill lease is acquired.

Confidence Score: 5/5

The PR appears safe to merge because no blocking failure remains within the eligible follow-up-review scope.

No blocking failure remains.

Important Files Changed

Filename	Overview
packages/pi-plugin/src/index.ts	Reworks persistent-process initialization, child-session suppression, startup maintenance, project registration, and session-scoped shutdown.
packages/pi-plugin/src/dreamer/index.ts	Adds process-shared owner-aware Dreamer registration, handoff, manual-run validation, and owner-scoped draining.
packages/pi-plugin/src/commands/pi-command-utils.ts	Introduces command-context-bound RPC notifications and dialogs while retaining model-invisible status entries.
packages/pi-plugin/src/subagent-runner.ts	Selects supported Pi launch targets without accidentally reusing an embedded host executable.
packages/pi-plugin/src/context-handler.ts	Defers session-history loading until the durable project-backfill lease permits the scan.
packages/pi-plugin/src/pi-recomp-runner.ts	Keys in-flight recomp work by session so one session does not drain another session’s tasks.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
  H[Persistent pi-web process] --> S1[Pi session A]
  H --> S2[Pi session B]
  S1 --> C1[Session-scoped context and background work]
  S2 --> C2[Session-scoped context and background work]
  S1 --> D[Process-shared Dreamer registry]
  S2 --> D
  D --> O[Active project owner]
  O --> T[Scheduled and manual Dreamer runs]
  H --> M[Once-per-process startup maintenance]
  S1 --> R1[Live RPC command context A]
  S2 --> R2[Live RPC command context B]
  R1 --> U1[Session A notifications and dialogs]
  R2 --> U2[Session B notifications and dialogs]

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_{Reviews (6): Last reviewed commit: "fix(pi-plugin): require owners for manua..." | Re-trigger Greptile}

Context used:

• Knowledge Base — Pi plugin integration
• Knowledge Base — Pi session context and memory

[cubic-dev-ai]

All reported issues were addressed across 17 files

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[cubic-dev-ai]

All reported issues were addressed across 17 files

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[alfonso-magic-context]

Thanks for this — especially as a first contribution. The diagnosis is right: the #247 process-global latch is what makes the second pi-web session skip Magic Context entirely, and routing child suppression through subagents:child:session-created/disposed plus AsyncLocalStorage is the correct seam. Once-per-process startup maintenance, not reusing a non-Pi argv[1], Dreamer sibling ownership, and keeping ctx-status entries model-invisible while presenting them in RPC are all the right instincts. And noted that you already pushed the Dreamer owner-handoff stabilization mid-review — that resolves one of the items we had flagged, and that kind of responsiveness makes this easy to shepherd.

Two clarifications so we don't talk past each other:

1. "RPC hosts" here is Pi RPC mode (ctx.ui.notify/ctx.ui.custom). It does not change Magic Context's RPC server, which must stay on 127.0.0.1 with a bearer token. We checked; this PR does not touch that.
2. The old "second init in the process is a no-op" test should change — that contract is the bug for pi-web. Please keep the child-only skip test (you did).

Before we can merge:

• Dreamer registeredProjects on globalThis (same jiti moduleCache:false reason as the child marker), so two sessions in one repo don't start two timers.
• session_shutdown draining only that session's in-flight work — in pi-web, shutdown is not process exit.
• RPC presentation using the command's live ctx, not a session_start closure.
• The #177 "never spawn bare pi" test kept alongside the new embedded-host test.
• packages/pi-plugin/PARITY.md updated for RPC dialogs, the multi-session process model, and the latch → ALS change.

We've approved CI for this PR so your next push gets the full check suite. Really solid work — happy to re-review quickly.

[cubic-dev-ai]

All reported issues were addressed across 21 files (changes from recent commits).

<sub>Tip: Review your code locally with the cubic CLI to iterate faster.

Re-trigger cubic</sub>

[cubic-dev-ai]

All reported issues were addressed across 4 files (changes from recent commits).

<sub>Tip: Review your code locally with the cubic CLI to iterate faster.

Re-trigger cubic</sub>

[elrond298]

Rebased onto the latest master (52e650c6) and force-pushed the updated branch. No functional changes were made as part of the rebase.