A per-cell timeout used to kill the persistent Python kernel, losing
all session state. The kernel.ts timeout path now sends SIGINT first
(letting the cell raise KeyboardInterrupt) and only escalates to
shutdown after a 5s grace window if the interrupt is ignored.
KernelExecuteResult gains an optional kernelKilled flag (defaulting to
false, propagated by the escalation timer and the unexpected-exit
handler). executor.ts formats two distinct timeout annotations: one
that says the kernel is still alive and reset:true would clear state,
one that says the kernel was killed and will be recreated.
- disposeAllKernelSessions removes sessions from the registry before awaiting shutdown, preventing queued work from seeing a registered-but-disposing session and spawning a replacement kernel.
- replaceSessionKernel re-checks registry membership after old-kernel shutdown and after starting a replacement, shutting the replacement down if the session was disposed mid-replace.
- owner-scoped disposal now preserves ownerIds when shutdown is unconfirmed so a later disposeKernelSessionsByOwner(ownerId) can retry.
- executeOnSession's runQueued callback now re-checks sessions.get(sessionId) === session at slot entry and before the dead-kernel replace retry; if the session was removed by disposeAllKernelSessions / disposeKernelSessionsByOwner / resetSession during the queue wait, the queued caller now rejects with PythonExecutionCancelledError instead of spawning an untracked replacement kernel on a stale session object.
- Both dispose paths now inspect KernelShutdownResult.confirmed and retain (or re-insert) sessions whose shutdown was unconfirmed or rejected, logging a warn so a later dispose can retry the kernel instead of orphaning the subprocess.
- Added `tools.artifactHeadBytes` and `tools.outputMaxColumns` settings with defaults in `SETTINGS_SCHEMA`.
- Expanded `OutputSink` with `headBytes`/`maxColumns` and middle truncate logic with elision markers and tracking.
- Updated output-meta to resolve sink settings, emit truncation metrics, and use `truncateMiddle` for spills.
- Integrated head and column limits into JS/Python/Bash/SSH/read output flows, with `:raw` skipping read truncation.
- Documented new output middle-elision and column-cap behavior in `CHANGELOG.md`.
- Added truncation tests for `OutputSink`, `truncateMiddle`, and read-tool line handling.
- Replaced Python execution with a local `python -u runner.py` subprocess and NDJSON stdin/stdout framing.
- Removed shared-gateway architecture, including coordinator lifecycle APIs, `useSharedGateway` wiring, and `jupyter` CLI/actions.
- Simplified setup checks to a plain Python 3 availability probe and removed automatic dependency-install fallbacks.
- Updated kernel cancellation and display processing to use status frames, SIGINT/SIGTERM escalation, and normalized output coercion.
- Added `python-runner` integration and display tests while deleting legacy websocket and kernel lifecycle test suites.
- Added parent-to-subagent artifact manager adoption so subagents reuse the parent `ArtifactManager` and write artifacts into a shared directory with shared IDs.
- Passed the shared artifact manager through tool/session context into subagent executor startup and exposed it via `SessionManager` and `ToolSession` for lookup.
- Updated kernel environment and artifact-resolution paths to prefer `PI_ARTIFACTS_DIR`, falling back to existing session-file-based behavior when absent.
The warmup path no longer produces prelude docs, so the cached-session
warmup it implemented added no value over the create-on-first-execute
path that withKernelSession already covers. Remove warmPythonEnvironment,
the backend warm() hook, the eval-tool warmup loop, the createTools
warmup preflight, and the forcePythonWarmup option. Simplify
ExecutorBackendCallOptions into ExecutorBackendExecOptions since execute
is now the only consumer.
- Added a unified eval framework with parser grammar, backend interfaces, and JS/Python execution result types.
- Added eval tool docs and updated prompts for fenced cells, `eval.py`/`eval.js`, and fallback behavior.
- Replaced the built-in `python` tool with `eval` across registry, rendering, interactive modes, and tool settings.
- Migrated Python execution runtime from `src/ipy` to `src/eval/py`, renamed state fields, and removed legacy introspection.
- Refactored browser tooling from in-process VM helpers to worker-managed tab supervisors and protocol transport.
- Added eval parser fallback and JS tool-bridge tests, updated imports, and removed obsolete python-mode suites.
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