feat: let opencode sub-agents delegate privately

CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- **opencode sub-agents can delegate privately.** `send_to_session` takes `private`, which
+  keeps the answer to its ticket: no note at the session's prompt, and only
+  `wait_for_answer` with that ticket returns it. Needs a lich with `lich send --private`.
+
 ## [0.13.1] - 2026-09-13
 
 ### Fixed

opencode/lich.js

@@ -171,10 +171,19 @@ async function lichTools($, helper) {
         prompt: s.string().describe("What to ask that session's agent to do."),
         project,
         timeout_seconds: s.number().optional().describe("Seconds to wait. Capped at 90."),
+        private: s
+          .boolean()
+          .optional()
+          .describe(
+            "Set this when you are a sub-agent running inside a session rather than the " +
+              "session's own agent. The answer is then yours alone: no note announces it at " +
+              "the session's prompt, and only wait_for_answer with this ticket returns it.",
+          ),
       },
       execute: (args) =>
         run([
           "send",
+          ...(args.private === true ? ["--private"] : []),
           ...flag("--project", args.project),
           "--timeout",
           String(waitSeconds(args.timeout_seconds)),

tests/opencode-tools.test.mjs

@@ -154,6 +154,21 @@ test('a task carries its target, its prompt and a bounded wait', async () => {
   assert.equal(shell.calls[3].args[2], '90')
 })
 
+test('private is only passed when it is really true', async () => {
+  const shell = fakeShell()
+  await inLich(shell, async (tools) => {
+    for (const value of [undefined, false, 'true', 1]) {
+      await tools.send_to_session.execute({ session: 'docs', prompt: 'x', private: value })
+    }
+    await tools.send_to_session.execute({ session: 'docs', prompt: 'x', private: true })
+  })
+
+  for (const call of shell.calls.slice(0, -1)) {
+    assert.ok(!call.args.includes('--private'), `--private sent for ${JSON.stringify(call.args)}`)
+  }
+  assert.deepEqual(shell.calls.at(-1).args, ['send', '--private', '--timeout', '90', 'docs', 'x'])
+})
+
 test('force is only passed when it is really true', async () => {
   const shell = fakeShell()
   await inLich(shell, async (tools) => {