OpenCode: 20 power-user tips

This round was different: I didn't study a release. I studied a rewrite still in progress, on the default branch, before it ships.

The eight lessons

1. Admit first, run later: the session_input inbox, steer and queue.
2. Never rewrite the system prompt: Context Epochs and mid-conversation updates.
3. Record once, replay forever: the http-recorder package.
4. Bound what the model sees: the tool-output store, 2,000 lines or 50 KB.
5. One API, even in-process: the embedded SDK's in-memory fetch.
6. Rebuild on the main branch: specs/v2 and the schema changelog.
7. Configured is not allowed: policy in one findLast.
8. Compact before you overflow: session/compaction.ts.

The lessons describe v2. The tips below are for OpenCode as it ships today, checked against its docs. The leader key is Ctrl+X by default.

20 power-user tips

In the TUI

1. Plan before you build. Tab switches between the Build and Plan agents. Plan asks before every file edit and shell command, so it's a safe place to explore.
2. Pull in files. Type @ for a fuzzy file search; the file's content is added to the conversation.
3. Run a command inline. Start a message with !, like !ls -la, and the output joins the conversation as a tool result.
4. Undo includes your files. /undo (Ctrl+X U) removes the last message and reverts the file changes it made; /redo brings them back. Your project needs to be a git repo.
5. Learn the leader key. Ctrl+X then N new session, L sessions, M models, C compact, T themes.
6. Write long prompts in your editor. /editor (Ctrl+X E) opens $EDITOR. /export (Ctrl+X X) saves the conversation as Markdown.
7. Change effort, not just visibility. Ctrl+T cycles model variants (reasoning effort). /thinking only shows or hides the thinking blocks.
8. Call a subagent by name. @general help me search for this function. Use Leader+↓ to jump into the child session it creates.
9. Let it write its own rules. /init walks you through creating or updating AGENTS.md.
10. Share a session. /share creates a link; /unshare removes it.

Make it yours

11. Custom commands are Markdown. .opencode/commands/test.md becomes /test. Use $ARGUMENTS, or $1, $2 for positional arguments.
12. Feed live output into a command. Inside a command file, !`git log --oneline -10` runs and inserts the output into the prompt.
13. Tune permissions per tool. In opencode.json: "permission": { "*": "ask", "bash": "allow", "edit": "deny" }.
14. Auto mode, with brakes. opencode --auto approves anything not explicitly denied. Your deny rules still apply.

Outside the TUI

15. One-shot runs. opencode run "Explain how closures work". Add --format json for raw JSON events.
16. Skip the cold start. Run opencode serve once, then opencode run --attach http://localhost:4096 "…" so MCP servers don't boot on every run.
17. Attach from anywhere. opencode attach http://host:4096 connects the TUI to a server running somewhere else.
18. Review a PR in one command. opencode pr 123 checks out the PR branch and starts OpenCode on it.
19. Summon it on GitHub. opencode github install sets up the app and workflow; then comment /opencode or /oc on an issue or PR and it runs in your Actions runner.
20. Know what it costs. opencode stats --days 7 --models shows token usage and cost, with a per-model breakdown.

What's next

Three codebases, three coding agents, three very different ideas of how to build one: compare them on the lessons page. The next codebase lands on X first: follow @tarekkh1997, or subscribe via RSS.