diff --git a/plugins/aidd-telemetry/README.md b/plugins/aidd-telemetry/README.md
index e918f3a0..bfbc5123 100644
--- a/plugins/aidd-telemetry/README.md
+++ b/plugins/aidd-telemetry/README.md
@@ -135,15 +135,20 @@ tokens; turning tokens into money is a separate service's job.
 - **Codex needs one interactive approval.** Its hook trust is per entry, and a headless run
   never sees the prompt — so a Codex session journals nothing until someone approves once,
   in an interactive session, and says nothing while it does not.
-- **OpenCode misses a server process's first session**, and `opencode run` is always a first
-  session. Measured, not asserted: one live `opencode 1.14.20` run (2026-08-31, started with
-  `--print-logs`) shows the plugin's own event hook firing for roughly 38 events of other
-  types, and its debug log shows `session.created` genuinely published on the bus after the
-  plugin loaded — yet it never reached the hook. Two further runs neither confirm nor refute
-  this: one without debug logging, one that captured no plugin events at all — see
-  `scripts/__tests__/fixtures/README.md`, "OpenCode's plugin events" for exactly what
-  each run shows. `session.idle` (the turn-end signal) is unaffected and reaches every
-  session.
+- **OpenCode never announces a session, so the plugin opens it.** Measured, not asserted:
+  one live `opencode 1.14.20` run (2026-08-31, started with `--print-logs`) shows the
+  plugin's own event hook firing for roughly 38 events of other types, and its debug log
+  shows `session.created` genuinely published on the bus after the plugin loaded — yet it
+  never reached the hook. Two further runs neither confirm nor refute this: one without
+  debug logging, one that captured no plugin events at all — see
+  `scripts/__tests__/fixtures/README.md`, "OpenCode's plugin events" for exactly what each
+  run shows. `session.idle` (the turn-end signal) is unaffected and reaches every session.
+  Since a session nobody announced would otherwise leave the journal with no run file — and
+  so drop the turn-end and every task declaration after it, for every `opencode run` there
+  has ever been — the first call a session produces opens it, carrying the directory that
+  call was already going to use. What is lost is only what `session.created` alone could
+  have said: on a server serving more than one directory, a session it never announced is
+  journalled under the plugin's own init-time directory rather than its own.
 - **A task is declared from a tool call's own arguments, on every host now.** Claude Code,
   Codex, Copilot and Cursor each hand their hook a tool call whose own arguments can name a
   file under a task folder — a `Read`, a `Bash` command line, an object keyed `path` — and
diff --git a/plugins/aidd-telemetry/hooks/opencode-plugin.js b/plugins/aidd-telemetry/hooks/opencode-plugin.js
index e7533e77..860fb0a1 100644
--- a/plugins/aidd-telemetry/hooks/opencode-plugin.js
+++ b/plugins/aidd-telemetry/hooks/opencode-plugin.js
@@ -48,12 +48,12 @@ function runJournal(event, payload) {
 // delivered" - see the fixtures' own README entry for that run's log and two further
 // attempts that could not distinguish the two.
 //
-// Every `opencode run` invocation is a first session, so this cache stays empty for it in
-// practice today, and `session.idle`/`message.part.updated` fall back to `input.directory`
-// below - this plugin's own init-time directory, which happens to be correct for the
-// single-directory case `opencode run` is. The plugin README already named this limit
-// ("OpenCode misses a server process's first session"); this comment is the same fact,
-// now anchored to a measurement rather than left as an assertion.
+// Every `opencode run` invocation is a session OpenCode never announced, so nothing fills
+// this cache from `session.created` there, and `session.idle`/`message.part.updated` fall
+// back to `input.directory` below - this plugin's own init-time directory, which is
+// correct for the single-directory case `opencode run` is. `journalCallsFor` writes that
+// same directory back into this cache when it opens such a session, so the session is
+// opened once and every later event reads the directory its own opening used.
 const directoryBySessionId = new Map();
 
 // Mirrors `lib/task-declared.cjs`'s own `TASK_PATH_PATTERN` and `lib/host.cjs`'s
@@ -118,8 +118,16 @@ function declaredTaskCallFor(event, sessionDirectories, fallbackDirectory) {
 /** One OpenCode event in, the journal call it produces out - or `null` for an event this
  * plugin does not act on. Pure but for the one map mutation `session.created` makes on
  * its way through: kept separate from `runJournal`'s spawn so a captured event can be
- * asserted against without running node as a child process. */
-export function journalCallFor(event, sessionDirectories, fallbackDirectory) {
+ * asserted against without running node as a child process.
+ *
+ * Reached as a property of the plugin below, never as a second named export. OpenCode's
+ * loader calls every function-valued export of a file in `plugin/` as a plugin factory of
+ * its own: measured against opencode 1.14.20 in a freshly installed project, this function
+ * exported beside the plugin was called with one argument, returned `null`, and `opencode
+ * run` died reading `.auth` off it before any session started - the tool this plugin
+ * measures, unusable in every project the framework had installed. A property is invisible
+ * to that loader, and a non-function export would have been ignored by it too. */
+function journalCallFor(event, sessionDirectories, fallbackDirectory) {
   if (event.type === "session.created") {
     const sessionId = event.properties.info.id;
     const cwd = event.properties.info.directory;
@@ -137,9 +145,50 @@ export function journalCallFor(event, sessionDirectories, fallbackDirectory) {
   return null;
 }
 
+/** The session id an event names, whichever field its own type carries it in. */
+function sessionIdOf(event) {
+  if (event.type === "session.created") return event.properties.info.id;
+  return event.properties.sessionID;
+}
+
+/** Every journal call one OpenCode event produces, in the order the journal must receive
+ * them - empty for an event this plugin does not act on.
+ *
+ * `journalCallFor` alone leaves `opencode run` measuring nothing. OpenCode publishes
+ * `session.created` on its own bus and never delivers it to a plugin's event hook
+ * (measured, 2026-08-31 - see plugins/aidd-telemetry/README.md, "OpenCode never announces a
+ * session"), and `opencode run` is always such a session. So the journal
+ * never receives a `session_start`, never creates the run file the rest of the session
+ * appends to, and drops the `turn-end` and every task declaration that follows - while
+ * `telemetryLocalRead` declares the tool covered and `aidd telemetry read`, which reads
+ * only sessions the run journal knows, can never find one. A declaration with nothing
+ * behind it, the same fault this plugin's own second export was.
+ *
+ * So the first call for a session nobody announced opens it. The `session-start` carries
+ * the directory that following call was already going to use - never a new guess: for a
+ * session no `session.created` named, that is this plugin's own init-time directory,
+ * exactly what `journalCallFor` already hands `turn-end` and `tool-used`. An announced
+ * session is untouched, and no session is opened twice. */
+function journalCallsFor(event, sessionDirectories, fallbackDirectory) {
+  const sessionId = sessionIdOf(event);
+  const announced = sessionId !== undefined && sessionDirectories.has(sessionId);
+  const call = journalCallFor(event, sessionDirectories, fallbackDirectory);
+  if (call === null) return [];
+  if (announced || call.script === "session-start") return [call];
+  sessionDirectories.set(sessionId, call.payload.cwd);
+  const opening = { tool: "opencode", session_id: sessionId, cwd: call.payload.cwd };
+  return [{ script: "session-start", payload: opening }, call];
+}
+
 export const AiddTelemetry = async (input) => ({
   event: async ({ event }) => {
-    const call = journalCallFor(event, directoryBySessionId, input.directory);
-    if (call) runJournal(call.script, call.payload);
+    for (const call of journalCallsFor(event, directoryBySessionId, input.directory)) {
+      runJournal(call.script, call.payload);
+    }
   },
 });
+
+// The spawn-free test seams, hung off the one export rather than standing beside it - see
+// journalCallFor's own comment for the measurement that rules out a second export.
+AiddTelemetry.journalCallFor = journalCallFor;
+AiddTelemetry.journalCallsFor = journalCallsFor;
diff --git a/scripts/__tests__/aidd-telemetry-cost-skill.test.js b/scripts/__tests__/aidd-telemetry-cost-skill.test.js
index f9904fe0..fb098c14 100644
--- a/scripts/__tests__/aidd-telemetry-cost-skill.test.js
+++ b/scripts/__tests__/aidd-telemetry-cost-skill.test.js
@@ -222,9 +222,17 @@ test("the plugin README gives every partly-measurable tool its reason, not just
     assert.ok(readme.includes(tool), `${tool} is named`);
     assert.ok(readme.includes(reason), `${tool}'s reason, not just its name`);
   }
+  // OpenCode's limit shrank rather than vanished: the plugin now opens a session OpenCode
+  // never announced, so a run is journalled and readable - but a session it never announced
+  // is journalled under the plugin's own directory, which is only right when the server
+  // serves one. Both halves are pinned: the fact, and what it still costs.
   assert.ok(
-    readme.includes("OpenCode misses a server process's first session"),
-    "OpenCode's own remaining limit is named, not silently dropped once it could declare a task"
+    readme.includes("OpenCode never announces a session"),
+    "OpenCode's unannounced session is named, not silently dropped once it could declare a task"
+  );
+  assert.ok(
+    readme.includes("journalled under the plugin's own init-time directory"),
+    "what an unannounced session still costs is named, not left as a solved problem"
   );
 });
 
diff --git a/scripts/__tests__/aidd-telemetry-opencode-payloads.test.js b/scripts/__tests__/aidd-telemetry-opencode-payloads.test.js
index c4e0d530..79c3b6a7 100644
--- a/scripts/__tests__/aidd-telemetry-opencode-payloads.test.js
+++ b/scripts/__tests__/aidd-telemetry-opencode-payloads.test.js
@@ -30,16 +30,124 @@ function loadFixture(name) {
 // `opencode-plugin.js` as CommonJS and choke on its `export` syntax. OpenCode's own loader
 // does not consult that field at all - the extension is the only thing that differs from
 // what ships.
-let journalCallForPromise;
-async function journalCallFor() {
-  if (!journalCallForPromise) {
+let pluginModulePromise;
+async function pluginModule() {
+  if (!pluginModulePromise) {
     const twin = path.join(fs.mkdtempSync(path.join(os.tmpdir(), "aidd-opencode-payloads-")), "opencode-plugin.mjs");
     fs.copyFileSync(PLUGIN_SOURCE, twin);
-    journalCallForPromise = import(pathToFileURL(twin).href).then((mod) => mod.journalCallFor);
+    pluginModulePromise = import(pathToFileURL(twin).href);
   }
-  return journalCallForPromise;
+  return pluginModulePromise;
+}
+
+async function journalCallFor() {
+  return (await pluginModule()).AiddTelemetry.journalCallFor;
+}
+
+async function journalCallsFor() {
+  return (await pluginModule()).AiddTelemetry.journalCallsFor;
 }
 
+// OpenCode loads every function-valued named export of a file in `plugin/` as a plugin
+// factory of its own. Measured live against opencode 1.14.20 in a freshly installed
+// project: a second such export returning `null` killed `opencode run` with
+// `TypeError: null is not an object (evaluating 'S.auth')` before any session started, so
+// installing this framework made the tool it measures unusable. A non-function export is
+// ignored by that same loader, which is why the spawn-free seam this file needs rides on
+// the plugin function as a property instead of standing beside it as a second export.
+test("the plugin file exports one plugin factory, never a second one OpenCode would call", async () => {
+  const exported = await pluginModule();
+  const factories = Object.keys(exported).filter((name) => typeof exported[name] === "function");
+  assert.deepEqual(factories, ["AiddTelemetry"]);
+});
+
+// `opencode run` is always a session OpenCode never announced: measured, `session.created`
+// is published on its own bus and never reaches a plugin's event hook (plugins/aidd-telemetry
+// /README.md, "OpenCode misses a server process's first session"). Without these four cases the
+// journal receives a turn-end for a run file that was never created, drops it, and every
+// OpenCode session reads back as nothing at all - while the tool is declared covered.
+test("session.idle for a session nobody announced opens it first, so the journal has a run file to write into", async () => {
+  const calls = await journalCallsFor();
+  const idle = loadFixture("opencode-session-idle.json");
+
+  const produced = calls(idle, new Map(), "/home/user/fallback");
+
+  assert.deepEqual(
+    produced.map((call) => call.script),
+    ["session-start", "turn-end"],
+  );
+  assert.deepEqual(
+    produced.map((call) => call.payload.cwd),
+    ["/home/user/fallback", "/home/user/fallback"],
+  );
+  assert.equal(detectHost(produced[0].payload), "opencode");
+});
+
+test("a task declaration in a session nobody announced opens it first too, never arriving before its own run file", async () => {
+  const calls = await journalCallsFor();
+  const part = loadFixture("opencode-tool-part-completed.json");
+
+  const produced = calls(part, new Map(), "/home/user/probe/project-opencode-task");
+
+  assert.deepEqual(
+    produced.map((call) => call.script),
+    ["session-start", "tool-used"],
+  );
+  assert.equal(produced[0].payload.session_id, produced[1].payload.session_id);
+});
+
+test("a session already announced is never opened a second time", async () => {
+  const calls = await journalCallsFor();
+  const sessionDirectories = new Map();
+
+  calls(loadFixture("opencode-session-created.json"), sessionDirectories, "/home/user/fallback");
+  const produced = calls(
+    loadFixture("opencode-session-idle.json"),
+    sessionDirectories,
+    "/home/user/fallback",
+  );
+
+  assert.deepEqual(
+    produced.map((call) => call.script),
+    ["turn-end"],
+  );
+});
+
+test("a session OpenCode did announce produces its one session-start, never a doubled one", async () => {
+  const calls = await journalCallsFor();
+
+  const produced = calls(
+    loadFixture("opencode-session-created.json"),
+    new Map(),
+    "/home/user/fallback",
+  );
+
+  assert.deepEqual(
+    produced.map((call) => call.script),
+    ["session-start"],
+  );
+});
+
+test("a second session.idle on one already-opened session adds no second session-start", async () => {
+  const calls = await journalCallsFor();
+  const idle = loadFixture("opencode-session-idle.json");
+  const sessionDirectories = new Map();
+
+  calls(idle, sessionDirectories, "/home/user/fallback");
+  const produced = calls(idle, sessionDirectories, "/home/user/fallback");
+
+  assert.deepEqual(
+    produced.map((call) => call.script),
+    ["turn-end"],
+  );
+});
+
+test("an event this plugin does not act on opens no session either", async () => {
+  const calls = await journalCallsFor();
+
+  assert.deepEqual(calls({ type: "message.updated", properties: {} }, new Map(), "/x"), []);
+});
+
 test("session.idle, captured live, turns into a turn-end call the journal recognises as opencode", async () => {
   const builder = await journalCallFor();
   const event = loadFixture("opencode-session-idle.json");