OwnCord/docs/plans/slash-commands.md

Plan: Slash command dispatcher in WS

Status: design only, not implemented Owner: TBD Tracks: deferred feature backlog (post-beta; see CHANGELOG "Deferred work") Estimated effort: 1–2 weeks of focused work

Why

Discord's command system is the primary surface every bot/app uses. OwnCord already ships:

• A plugin runtime (Server/plugin/) with a commands capability,
• plugin.Registry.RegisterCommand and plugin.Registry.DispatchCommand (Server/plugin/host_commands.go),
• A V2 WS dispatcher (Server/ws/handlers_chat.go, Server/ws/command.go) that already routes typed Command structs to pure handlers,
• A chat_send payload that flows through MessageService.SendMessage.

…but chat_send content beginning with / is currently treated as a literal message. There is no dispatcher that recognises /help, no autocomplete, no per-command argument schema, and the Registry.DispatchCommand plumbing is dead code.

This plan wires the existing pieces together and adds the surface that clients need to render slash commands the way Discord does.

Non-goals

• Not an OAuth2/app directory (Tier 2 work — separate plan).
• Not a hosted "verified bot" registry — local plugins only.
• Not modal interactions or buttons/select menus (component v2). These are a follow-up; the v1 surface is text reply + ephemeral reply.
• Not a re-implementation of MessageService — slash commands take a separate path so they don't pollute the message table.

Surface design

Wire format

Two new client→server messages:

// 1. Command invocation (from /chat input or autocomplete pick)
{
  "type": "command_invoke",
  "req_id": "c-42",
  "payload": {
    "channel_id": 17,
    "name": "kick",
    "args": [
      {"name": "user",   "value": "12345"},
      {"name": "reason", "value": "spam"}
    ]
  }
}

// 2. Autocomplete query (sent on every keystroke after `/`)
{
  "type": "command_autocomplete",
  "req_id": "c-43",
  "payload": {
    "channel_id": 17,
    "name": "kick",
    "focused": "user",
    "partial": "ali",
    "args": [{"name": "user", "value": "ali"}]
  }
}

Two new server→client messages:

// Successful invocation reply (ephemeral by default).
{
  "type": "command_reply",
  "req_id": "c-42",
  "payload": {
    "ephemeral": true,
    "content":   "Kicked alice for: spam.",
    "embeds":    [],
    "broadcast": null
  }
}

// Autocomplete suggestions.
{
  "type": "command_autocomplete_result",
  "req_id": "c-43",
  "payload": {
    "choices": [
      {"label": "alice (id 12345)", "value": "12345"},
      {"label": "alistair (id 67)", "value": "67"}
    ]
  }
}

The ephemeral reply is delivered only to the invoking client (it never hits MessageSentChannelEvent). The optional broadcast field, when non-null, becomes a real chat_message posted by a synthetic Bot:<plugin-name> identity so the channel timeline records it.

Manifest changes

Plugin manifests gain a commands block. The manifest is the source of truth for the per-command schema; the runtime never trusts what the plugin says at dispatch time. Example:

{
  "name": "moderation-tools",
  "version": "0.2.0",
  "entrypoint": "mod.wasm",
  "permissions": ["commands", "events"],
  "commands": [
    {
      "name": "kick",
      "description": "Remove a user from the server.",
      "default_member_permissions": ["kick_members"],
      "options": [
        {
          "name": "user",
          "type": "user",
          "description": "Who to kick.",
          "required": true,
          "autocomplete": true
        },
        {
          "name": "reason",
          "type": "string",
          "description": "Optional reason recorded in audit log.",
          "max_length": 256
        }
      ]
    }
  ]
}

Manifest.Validate (Server/plugin/manifest.go) gets a new validateCommands() step:

• name: same regex as plugin names (^[a-z][a-z0-9_-]{0,31}$), forced lowercase, no spaces, no slashes, max 32 chars.
• description: 1–100 chars, no NUL/control bytes.
• options: max 25, each name unique, recurses on nested groups.
• option.type: closed enum (string, int, bool, user, channel, role, mention, attachment, subcommand, subcommand_group).
• default_member_permissions: closed enum matched against permissions.Permission constants (so a typo fails at install, not at dispatch).

Same defense profile as the existing manifest validation: the closed-set checks live in manifest.go next to validCapabilities.

Schema additions

A new table to support server-installed plugin commands without duplicating the manifest — needed so the WS hub can answer command_autocomplete requests without doing a JSON walk on every keystroke:

-- migrations/016_plugin_commands.sql
CREATE TABLE plugin_commands (
    plugin_id    INTEGER NOT NULL REFERENCES plugins(id) ON DELETE CASCADE,
    name         TEXT    NOT NULL,
    schema_json  TEXT    NOT NULL,         -- the validated `commands[i]` blob
    permissions  INTEGER NOT NULL DEFAULT 0, -- packed permission bits
    PRIMARY KEY (plugin_id, name)
);
CREATE UNIQUE INDEX plugin_commands_name_uq ON plugin_commands(name);

The unique index on name enforces that two enabled plugins can't both own /ban — install of the second one fails. This is intentional: command namespace collisions are confusing for users.

Code surface

File	Change
Server/ws/message_types.go	Add MsgTypeCommandInvoke, MsgTypeCommandAutocomplete, MsgTypeCommandReply, MsgTypeCommandAutocompleteResult.
Server/ws/command.go	Add CommandInvokeCmd, CommandAutocompleteCmd structs and constructors. Validate name regex + arg count cap (25) at parse time so the dispatcher trusts its input.
Server/ws/handlers_command.go	New file. handleCommandInvokeV2, handleCommandAutocompleteV2. Pure handlers — return a Result like the existing chat handlers.
Server/ws/handlers.go	Register the new handlers via r.RegisterV2(MsgTypeCommandInvoke, handleCommandInvokeV2, deps).
Server/ws/deps.go	Add a CommandDeps carrying *plugin.Registry, service.PermissionService, and service.MessageService.
Server/plugin/host_commands.go	Extend DispatchCommand to take a typed arg map (map[string]any) instead of []string. Add Autocomplete(ctx, name, focused, partial).
Server/plugin/manifest.go	Add Commands []CommandSpec to Manifest, validateCommands(), and a Manifest.Command(name) lookup.
Server/store/sqlite_plugin_commands.go	New file. CRUD over the plugin_commands table.
Server/migrations/016_plugin_commands.sql	New migration.
Client/tauri-client/src/state/commands.ts	New module. Caches per-server command list (fetched at auth_ok time via a new commands_list REST endpoint), feeds the autocomplete UI.
Client/tauri-client/src/components/Composer/SlashCommandPopup.tsx	New component — autocomplete dropdown that opens when the message buffer starts with /.
docs/protocol.md	Document the four new wire messages.

Permission model

default_member_permissions is enforced server-side in handleCommandInvokeV2 before the plugin is invoked, by calling PermissionService.HasChannelPerm for each declared permission. Plugins do not get to decide who can use their commands; the manifest declares, the host enforces.

Slash commands inherit the existing channel ACL: command_invoke for a channel the user can't view_channel in returns ErrCodeForbidden with no plugin invocation, no telemetry leak.

Built-in commands

Two slash commands ship in-tree (no plugin required), to validate the dispatcher and to give bare-metal deployments something useful:

Command	Implementation	Why in-tree
/me <text>	Built-in handler in handlers_command.go	Discord parity, IRC tradition.
/shrug	Built-in handler	Same. Trivial.

A future PR can add /poll, /remind, /nick etc. — all should follow the same handler shape so a plugin author can read the source as the canonical example.

Concurrency & lifecycle

• Plugin command registration happens at Registry.activateAll time (already exists for the wazero build) and at installFromDisk for the default build.
• plugin_commands rows are written inside the same transaction as plugins so a half-installed plugin can never have orphan rows.
• DispatchCommand runs the plugin handler off the WS goroutine with a 3 s context deadline (configurable via config.yaml > plugins.command_deadline_ms). A slow command must not block chat_send for the same client.
• The 3 s budget is enforced by passing context.WithTimeout into Registry.DispatchCommand; the wazero runtime already accepts a ctx on every host call.

Failure modes & UX

Failure	Server response	Client UX
No such command	command_reply ephemeral: Unknown command: /foo	Red banner under composer.
Plugin runtime not built (default build)	Existing fallback in DispatchCommand returns the helpful error message	Same banner, no crash.
Plugin handler timeout (>3s)	command_reply ephemeral: /foo timed out + audit log entry	Banner + telemetry tag.
Plugin handler panics	Recovered in the runtime, ephemeral error, plugin auto-disabled after 3 panics in 60s	Banner + plugin marked unhealthy in admin panel.
Permission denied	command_invoke returns ErrCodeForbidden before invocation	Banner: "You lack permission".
Argument validation fails	command_invoke returns ErrCodeBadPayload with the field name	Composer highlights the bad option.

Testing strategy

Unit:

• manifest_test.go — extend with command validation (name regex, option type enum, max 25 options, max 100 char description).
• host_commands_test.go — DispatchCommand with a stub Instance, arg-map round trip, auto-disable after panics.
• handlers_command_test.go — pure handler test using the existing V2 test pattern (stubMessageSvc, stubPermSvc).

Integration:

• Add a new in-tree test plugin under Server/plugin/examples/echo (no wasm needed — installable via the default build) that registers /echo and is loaded inside ws_integration_test.go.

Contract:

• docs/protocol.md round trip — JSON examples kept in sync with the parser via golden tests.

Telemetry

Three new counters under commands_*:

• commands_invoked_total{name,plugin,result}
• commands_autocomplete_total{name,plugin}
• commands_duration_ms_bucket{name,plugin} (histogram)

Existing OTel skeleton (Server/telemetry/) gets a new tracer.Start(ctx, "command.invoke") span around DispatchCommand.

Rollout

1. Land schema migration + manifest validation behind the existing default build. New plugins can declare commands but the WS dispatcher still treats / as plain text.
2. Land WS dispatcher + /me / /shrug built-ins. Slash commands work for in-tree handlers, plugin commands still no-op.
3. Land the autocomplete RPC + client UI. Composer learns to open the popup on /.
4. Land Registry.DispatchCommand wiring so plugin commands route through. Gate behind -tags wazero for the actual invocation; the default build returns the existing helpful "runtime not built" message.

Each step is independently shippable.

Open questions

1. Bot identity for broadcast replies. When a slash command produces a broadcast, who is the author? Options: (a) a virtual Bot:<name> user with a synthetic ID in a reserved namespace, (b) the invoking user (Discord style: "Used /poll"). I'm leaning (b) for simplicity — it avoids new identity rows — but it loses the visual distinction. TBD in review.
2. Component v2 (buttons / selects). Out of scope for v1 but the wire-format reservations should leave room for a components array on command_reply. Worth adding the field as []any now even though nothing renders it, so v2 isn't a breaking change.
3. Cross-plugin command imports. Discord allows one app to use another's commands. We don't, and shouldn't until there's a real reason — the namespace flatness is a feature for a self-hosted product.
4. DM-context commands. Some commands make sense in DMs (/poll), some don't (/kick). Add a manifest field contexts: ["channel", "dm"] defaulting to ["channel"].

Files-to-touch checklist (for the implementing agent)

• Server/migrations/016_plugin_commands.sql
• Server/plugin/manifest.go — CommandSpec, validateCommands
• Server/plugin/manifest_test.go — command validation table
• Server/plugin/host_commands.go — typed args, autocomplete
• Server/store/sqlite_plugin_commands.go
• Server/ws/message_types.go — four new constants
• Server/ws/command.go — CommandInvokeCmd, CommandAutocompleteCmd
• Server/ws/handlers_command.go — V2 handlers + /me + /shrug
• Server/ws/handlers.go — register new handlers
• Server/ws/deps.go — CommandDeps
• Server/ws/handlers_command_test.go
• Server/api/router.go — GET /api/v1/commands (cached schema dump)
• Client/tauri-client/src/state/commands.ts
• Client/tauri-client/src/components/Composer/SlashCommandPopup.tsx
• docs/protocol.md — four new wire messages
• CHANGELOG.md — Phase D entry