The RPC transport did not treat cancellation as an independent, resettable
control plane, so two lifecycle contract violations shared a root cause:
A. Server-side: the stdin loop in `rpc-mode.ts` awaited each commands
`handleCommand` before pulling the next frame, so `abort_bash` queued
behind the `bash` it must cancel. Extracted `dispatchRpcInputFrame` and
dispatch `bash` in the background: the input loop keeps reading, so
`abort_bash` (or any other command) can preempt an in-flight shell.
Response correlation still rides `command.id`; ordering across
concurrent commands is documented as not guaranteed.
B. Client-side: `RpcClient.stop()` aborted the shared `#abortController`
but never replaced it, so a subsequent `start()` handed a pre-aborted
signal to `readJsonl` and the stdout reader exited immediately with a
spurious "Agent process exited before ready" while the spawned child
leaked in `#process`. Mint a fresh `AbortController` inside `start()`
and clean up the child on any post-spawn failure.
Adds:
- `dispatchRpcInputFrame` unit tests covering the concurrent bash + abort
ordering, serial dispatch of other commands, and background error
reporting.
- `RpcClient` lifecycle tests covering start->stop->start on the same
instance (via a mock fixture agent) and retry after a failed start.
- Documents the bash concurrency contract in `docs/rpc.md`.
Fixes#4079
- Added host tool execution framework with HostTool, HostToolContext, and host_tool() factory for custom tool integration.
- Added RpcConcurrencyError exception and _PromptLifecycleCoordinator to enforce single-flight constraint on prompt lifecycle methods.
- Enhanced JSON parsing with 10 validation helpers and enum frozensets for safe field extraction with detailed error messages.
- Replaced manual event/error list management with _BoundedHistory for bounded-size history with offset tracking.
- Added deep JSON cloning to prevent external mutations of stored payloads and improved UTF-8 error handling in subprocess stderr.
- Added custom_tools parameter to RpcClient and set_custom_tools() method for runtime tool registration.
- Added typed event listeners and granular event handling for all RPC notification types.
- Added set_todos RPC command and todoPhases session state field for todo phase management.
- Added RpcClient initialization parameters (thinking, tools, no_session, rpc_defaults) for startup configuration.
- Added install_headless_ui() method and todo management methods (get_todos, set_todos, clear_todos).
- Added TodoItem and TodoPhase dataclasses with parser functions for structured todo representation.
- Added RPC mode behavior: disables session title generation by default and resets workflow settings to built-in defaults.
- Moved documentation files from packages/coding-agent/docs/ to root docs/ directory to flatten the documentation structure.
- Updated all internal documentation links to account for the new file locations, adjusting relative paths to maintain correct references across the monorepo.
- Updated README.md and issue template configuration to reference documentation at the new root docs/ location instead of packages/coding-agent/docs/.
roboomp