feat: add OpenCode adapter

Thin OpenCode plugin injecting the ponytail ruleset via experimental.chat.system.transform, reusing the shared instruction builder. Verified end-to-end on OpenCode 1.17.4. Supersedes #15.
2026-06-13 03:20:44 +02:00
parent 1556f10bc6
commit 46c5c28b35
8 changed files with 156 additions and 1 deletions
@@ -0,0 +1,65 @@
+// ponytail — OpenCode plugin.
+//
+// Injects the ponytail ruleset into every chat's system prompt at the active
+// intensity, and persists /ponytail mode switches. Reuses the shared instruction
+// builder so Claude Code, Codex, pi, and OpenCode all read one source of truth.
+//
+// OpenCode loads this as a server plugin — add it to your opencode.json:
+//   { "plugin": ["./.opencode/plugins/ponytail.mjs"] }
+
+import { createRequire } from 'module';
+import fs from 'fs';
+import os from 'os';
+import path from 'path';
+
+// The shared instruction builder is CommonJS; bridge to it from this ES module.
+const require = createRequire(import.meta.url);
+const { getPonytailInstructions } = require('../../hooks/ponytail-instructions');
+const { getDefaultMode, normalizePersistedMode } = require('../../hooks/ponytail-config');
+
+// OpenCode has no flag-file convention of its own; keep mode beside its config.
+const statePath = path.join(
+  process.env.XDG_CONFIG_HOME || path.join(os.homedir(), '.config'),
+  'opencode',
+  '.ponytail-active',
+);
+
+function readMode() {
+  try {
+    return normalizePersistedMode(fs.readFileSync(statePath, 'utf8').trim()) || getDefaultMode();
+  } catch (e) {
+    return getDefaultMode();
+  }
+}
+
+function writeMode(mode) {
+  fs.mkdirSync(path.dirname(statePath), { recursive: true });
+  fs.writeFileSync(statePath, mode);
+}
+
+export default async ({ client } = {}) => {
+  const log = (level, message) => {
+    try { client && client.app && client.app.log({ body: { service: 'ponytail', level, message } }); } catch (e) {}
+  };
+
+  return {
+    // Append the ruleset to the system prompt every turn.
+    'experimental.chat.system.transform': async (_input, output) => {
+      const mode = readMode();
+      if (mode === 'off') return;
+      output.system.push(getPonytailInstructions(mode));
+    },
+
+    // Persist `/ponytail <level>` so the next turn's injection follows it.
+    // ponytail: mode applies from the next message, not the current one — the
+    // transform reads the flag the command writes. Good enough; switch to a
+    // synchronous store if same-turn switching ever matters.
+    'command.execute.before': async (input) => {
+      if (!input || input.command !== 'ponytail') return;
+      // `off` is persisted like any mode; the transform reads it and stays silent.
+      const mode = normalizePersistedMode((input.arguments || '').trim()) || getDefaultMode();
+      writeMode(mode);
+      log('info', 'ponytail ' + mode);
+    },
+  };
+};