Adding a CLI command to Neru

Neru is a daemon plus a thin CLI. Almost every command serializes an IPC request to the running daemon over its per-user Unix socket or Windows named pipe. A new command therefore touches three layers plus docs. Skipping the IPC layer and calling app code directly from internal/cli is wrong even when it compiles.

The chain

1. Cobra command in internal/cli/<name>.go, registered in an init() like its siblings. Mode-shaped commands (hints/grid/scroll variants) go through BuildModeCommand(ModeConfig{...}) in command_builders.go instead of hand-rolling cobra. Look at hints.go first. Long help text follows the house style: prose, then flag explanations, then an Examples: block.
2. IPC transport is already generic (internal/adapter/ipc), so you only add an action string. Keep the wire shape in one place and reuse existing request helpers in internal/cli/cliutil.
3. IPC handler in internal/app/ipcctrl. Handlers register into Controller.Handlers via the sub-controller for their family (lifecycle, modes, actions, info, overlay, scroll, …). Extend the matching RegisterHandlers, and don't add a case to the controller.
4. The actual work lives in internal/app/services/* or a mode, never in the handler. Handlers parse, delegate, and shape the ipc.Response.
5. Man pages: regenerate with just genman (backed by ./cmd/genman). Cobra metadata is the source, so if the man page reads wrong, fix the command's Short/Long, not the output.
6. Docs: update docs/reference/cli.md. It is the single home for CLI reference facts.
7. IPC reference: a new IPC command gets a row in the Commands table of docs/reference/ipc.md. internal/architecture/ipc_reference_test.go fails while the table and the commands the daemon answers differ.
8. Schemas: when a reply type changes, run just genschema. internal/architecture/ipc_schema_test.go fails while schemas/ipc.schema.json is out of date.

Mode flags are different

A flag on a mode command (hints --action left_click) is not registered by hand. It is one entry in the descriptor table in internal/domain/modecmd, carrying its own parse, its own render, and the modes that accept it. That entry is what offers the flag on the command line, what the daemon and the config validator read it with, and what writes its row in the reference.

After adding, removing or re-wording one, run just genflagref to rewrite the generated region of docs/reference/cli.md. An architecture test (internal/architecture/mode_flag_contract_test.go) fails while a descriptor is unregistered or missing from that region, and while a mode command offers a flag the table never declared.

Tests

• Command wiring and flag parsing: follow the table-driven patterns in internal/cli/cli_test.go / *_internal_test.go.
• Handler behavior: internal/app/ipcctrl/*_test.go with port mocks from internal/ports/mocks. Assert the response shape and that the right service call happened, not internals.
• Anything platform-gated must degrade with derrors.CodeNotSupported, and a contract test pins that (root AGENTS.md, "Hard rules").

Verify

just build
./bin/neru <command> --help     # against a running daemon: ./bin/neru launch
just genman

Then the standard pre-commit gate from AGENTS.md.