feat: Integrate plugin commands from upstream PR #4411

[shuv1337]

Summary

Integrate the plugin commands feature from upstream PR sst/opencode#4411 which allows plugins to register custom slash commands that execute code.

Context

The upstream PR adds a powerful new plugin.command hook that enables plugins to register their own /commands in the TUI. This unlocks use cases like:

• /prune - prune tool outputs from session
• Toggling plugin features on/off
• Creating composable workflows
• Custom session manipulation commands

Acceptance Criteria

• Plugin commands appear in autocomplete when typing /
• Plugin commands with sessionOnly: true only show when a session exists
• Command aliases work (e.g., /hi resolves to /hello)
• Plugin command execution works with error handling
• SDK types are updated with sessionOnly and aliases fields
• SDK rebuild works (cd packages/sdk/js && bun run script/build.ts)

Implementation Details

Files to Update

File	Changes
packages/plugin/src/index.ts:145-192	Add plugin.command hook interface to Hooks
packages/opencode/src/plugin/index.ts:53-76	Exclude plugin.command from trigger, add client() export
packages/opencode/src/command/index.ts:23-79	Add sessionOnly/aliases to schema, load plugin commands, support alias lookup
packages/opencode/src/session/prompt.ts:1413-1498	Execute plugin commands with error handling
packages/opencode/src/cli/cmd/tui/component/prompt/autocomplete.tsx:207-222	Filter sessionOnly commands, add aliases to options
packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx:506-518	Resolve command aliases
packages/sdk/js/src/gen/types.gen.ts	Add sessionOnly to Command type
packages/sdk/js/src/v2/gen/types.gen.ts	Add sessionOnly and aliases to Command type

Key Changes

1. New Plugin Hook Interface (packages/plugin/src/index.ts)

"plugin.command"?: {
  [key: string]: {
    description: string
    aliases?: string[]
    sessionOnly?: boolean
    execute(input: { sessionID?: string; client: ReturnType<typeof createOpencodeClient> }): Promise<void>
  }
}

2. Command Schema Updates (packages/opencode/src/command/index.ts)

// Add to Command.Info schema
sessionOnly: z.boolean().optional(),
aliases: z.array(z.string()).optional(),

3. Plugin Command Loading (packages/opencode/src/command/index.ts)

const plugins = await Plugin.list()
for (const plugin of plugins) {
  const commands = plugin["plugin.command"]
  if (!commands) continue
  for (const [name, cmd] of Object.entries(commands)) {
    if (result[name]) continue
    result[name] = {
      name,
      description: cmd.description,
      template: "",
      sessionOnly: cmd.sessionOnly,
      aliases: cmd.aliases,
    }
  }
}

4. Plugin Command Execution (packages/opencode/src/session/prompt.ts)

• Check for plugin commands before built-in commands
• Execute with { sessionID, client } context
• Handle errors gracefully with user feedback

Example Plugin Command

import type { Plugin } from "@opencode-ai/plugin"

export const CommandsPlugin: Plugin = async (ctx) => {
  return {
    "plugin.command": {
      hello: {
        description: "Say hello",
        aliases: ["hi"],
        sessionOnly: true,
        async execute({ sessionID, client }) {
          await client.session.sendMessage({
            path: { id: sessionID! },
            body: { content: "Hello from plugin command!" },
          })
        },
      },
    },
  }
}

Tasks

• Cherry-pick or manually apply changes from upstream PR
• Verify no conflicts with fork-specific changes
• Rebuild SDK: cd packages/sdk/js && bun run script/build.ts
• Test plugin command registration
• Test autocomplete with sessionOnly filtering
• Test alias resolution
• Test error handling for failed plugin commands
• Run full test suite

References

• Upstream PR: feat(plugin commands): allows for code execution on plugin registered slash commands anomalyco/opencode#4411
• PR Diff: gh pr diff 4411 --repo sst/opencode