Add Codex plugin sharing a host-agnostic stop-hook core

.agents/plugins/marketplace.json

@@ -0,0 +1,20 @@
+{
+  "name": "mainframe",
+  "interface": {
+    "displayName": "Mainframe"
+  },
+  "plugins": [
+    {
+      "name": "mainframe",
+      "source": {
+        "source": "url",
+        "url": "https://github.com/mainframecomputer/mainframe-plugins.git"
+      },
+      "policy": {
+        "installation": "AVAILABLE",
+        "authentication": "ON_INSTALL"
+      },
+      "category": "Productivity"
+    }
+  ]
+}

.codex-plugin/plugin.json

@@ -0,0 +1,24 @@
+{
+  "name": "mainframe",
+  "version": "0.1.0",
+  "description": "Create and share short video updates from agent work.",
+  "author": {
+    "name": "Mainframe",
+    "email": "support@mainframe.app"
+  },
+  "homepage": "https://mainframe.app",
+  "repository": "https://github.com/mainframecomputer/mainframe-plugins.git",
+  "license": "UNLICENSED",
+  "keywords": ["mainframe", "agent-skills", "mcp", "hooks", "video"],
+  "skills": "./skills",
+  "mcpServers": "./.mcp.json",
+  "hooks": "./hooks/codex/hooks.json",
+  "interface": {
+    "displayName": "Mainframe",
+    "shortDescription": "Create and share short video updates from agent work.",
+    "longDescription": "Watch what your agents did instead of reading through all of it. Each task wraps up with a short narrated video in your own voice and company branding, so you stay up to date at a glance and can share it with your team.",
+    "developerName": "Mainframe",
+    "category": "Productivity",
+    "logo": "./assets/logo.png"
+  }
+}

.cursor-plugin/marketplace.json

@@ -5,13 +5,13 @@
     "email": "support@mainframe.app"
   },
   "metadata": {
-    "description": "Create and share short Mainframe video updates from coding-agent work."
+    "description": "Create and share short video updates from agent work."
   },
   "plugins": [
     {
       "name": "mainframe",
       "source": ".",
-      "description": "Create and share short Mainframe video updates from coding-agent work."
+      "description": "Create and share short video updates from agent work."
     }
   ]
 }

.cursor-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "mainframe",
   "version": "0.1.0",
-  "description": "Create and share short Mainframe video updates from coding-agent work.",
+  "description": "Create and share short video updates from agent work.",
   "author": {
     "name": "Mainframe",
     "email": "support@mainframe.app"

AGENTS.md

@@ -1,20 +1,22 @@
 # Agent notes
 
-This repository packages the Mainframe Cursor plugin. Keep it focused on the Cursor
-manifest, hosted MCP wiring, the `share-video` skill, and the stop hook.
+This repository packages the Mainframe Cursor and Codex plugins. Keep it focused on the
+Cursor and Codex manifests, hosted MCP wiring, the `share-video` skill, and the stop hooks.
 
 ## Repository boundaries
 
 - User-visible copy should say "Mainframe", not legacy product names.
 - Do not add secrets, customer data, private URLs, or private business context.
-- Do not add non-Cursor host surfaces unless the product task explicitly asks for them.
+- Cursor and Codex are the supported hosts. Both plugins share the repo root, the
+  `share-video` skill, the `./.mcp.json` wiring, and the `hooks/core` runtime. Do not add
+  other host surfaces unless the product task explicitly asks for them.
 - Run `bun run verify` before considering changes ready.
-- Generated Cursor manifest and marketplace files come from `tooling/generate.ts`; edit
-  the config there, then run `bun run generate`.
+- Generated Cursor and Codex manifest and marketplace files come from `tooling/generate.ts`;
+  edit the config there, then run `bun run generate`.
 - The canonical skill is `skills/share-video/SKILL.md`.
-- Keep generated metadata in `.cursor-plugin/`. Do not add package-local docs
-  or extra top-level markdown unless the user asks; improve `README.md` or this
-  file instead.
+- Keep generated metadata in `.cursor-plugin/`, `.codex-plugin/`, and `.agents/plugins/`. Do
+  not add package-local docs or extra top-level markdown unless the user asks; improve
+  `README.md` or this file instead.
 
 ## Start here
 

README.md

@@ -1,7 +1,7 @@
-# Mainframe skills
+# Mainframe plugins
 
 Mainframe is the video sharing platform for agents. This repository ships the `share-video` skill
-and a Cursor plugin.
+and Mainframe plugins for Cursor and Codex.
 
 ## Install
 
@@ -17,8 +17,21 @@ To preview the available skills without installing:
 npx skills add mainframecomputer/mainframe-plugins --list
 ```
 
-If you use Cursor, you can install the Mainframe plugin from the Cursor marketplace instead. The
-plugin includes the `share-video` skill and Mainframe tools.
+### Cursor
+
+Install the Mainframe plugin from the Cursor marketplace. It gives your agent the `share-video`
+skill and Mainframe tools so it can create and share short video updates of its work.
+
+### Codex
+
+Add this repository as a Codex plugin marketplace, then install Mainframe from the `/plugins`
+browser in the Codex CLI:
+
+```sh
+codex plugin marketplace add mainframecomputer/mainframe-plugins
+```
+
+The Codex plugin gives Codex the same `share-video` skill and Mainframe tools as the Cursor plugin.
 
 ## Included skill
 

dist/hooks/codex/stop-evaluator.js

@@ -0,0 +1,26 @@
+import { decideStop } from "../core/stop-policy.js";
+import { parseJsonRecord } from "../core/json.js";
+import { summarizeCodexTranscriptFile } from "./transcript.js";
+export function evaluateCodexStopHook(input) {
+    const hookInput = parseCodexStopInput(input.stdin);
+    if (hookInput === null || hookInput.stopHookActive) {
+        return {};
+    }
+    const summary = summarizeCodexTranscriptFile(hookInput.transcriptPath);
+    const decision = decideStop(summary, input.nowMs ?? Date.now());
+    if (decision.kind === "skip") {
+        return {};
+    }
+    return { decision: "block", reason: decision.message };
+}
+function parseCodexStopInput(stdin) {
+    const input = parseJsonRecord(stdin);
+    if (input === null || input.hook_event_name !== "Stop") {
+        return null;
+    }
+    const transcriptPath = input.transcript_path;
+    if (typeof transcriptPath !== "string" || transcriptPath.trim() === "") {
+        return null;
+    }
+    return { transcriptPath, stopHookActive: input.stop_hook_active === true };
+}

dist/hooks/codex/stop.js

@@ -0,0 +1,4 @@
+#!/usr/bin/env node
+import { runStopHookCli } from "../core/run-stop-hook.js";
+import { evaluateCodexStopHook } from "./stop-evaluator.js";
+runStopHookCli(evaluateCodexStopHook);

dist/hooks/codex/transcript.js

@@ -0,0 +1,81 @@
+import { hasMainframeVideoUrl, isNonEmptyString, nextUserTimeMs, summarizeTranscript, summarizeTranscriptFile, } from "../core/transcript.js";
+import { isJsonRecord, parseJsonlRecords } from "../core/json.js";
+export function summarizeCodexTranscriptFile(path) {
+    return summarizeTranscriptFile(path, parseCodexRows);
+}
+export function summarizeCodexTranscript(text) {
+    return summarizeTranscript(text, parseCodexRows);
+}
+// Codex rollout files are append-only JSONL where every line is
+// `{ timestamp, type, payload }`. The format carries many event types that are
+// irrelevant here, so unrecognized-but-valid rows are ignored. Anything that
+// makes the transcript untrustworthy fails closed (returns "unreadable" so the
+// hook never fires): non-JSON or non-object rows, a missing `session_meta` row,
+// or user timestamps that move backwards.
+function parseCodexRows(text) {
+    const records = parseJsonlRecords(text);
+    if (records === "unreadable") {
+        return "unreadable";
+    }
+    let sawSessionMeta = false;
+    let sawUser = false;
+    let lastUserTimeMs = null;
+    let workHappened = false;
+    let alreadyShared = false;
+    let previousUserTimeMs = null;
+    for (const record of records) {
+        const kind = classifyCodexRow(record);
+        if (kind === "session-meta") {
+            sawSessionMeta = true;
+            continue;
+        }
+        if (kind === "user") {
+            const userTimeMs = nextUserTimeMs(record.timestamp, previousUserTimeMs);
+            if (userTimeMs === "unreadable") {
+                return "unreadable";
+            }
+            sawUser = true;
+            lastUserTimeMs = userTimeMs;
+            if (userTimeMs !== null) {
+                previousUserTimeMs = userTimeMs;
+            }
+            workHappened = false;
+            alreadyShared = false;
+            continue;
+        }
+        if (sawUser) {
+            workHappened = workHappened || kind === "work";
+            alreadyShared = alreadyShared || hasMainframeVideoUrl(record);
+        }
+    }
+    if (!sawSessionMeta) {
+        return "unreadable";
+    }
+    return { sawUser, lastUserTimeMs, workHappened, alreadyShared };
+}
+function classifyCodexRow(record) {
+    if (record.type === "session_meta") {
+        return "session-meta";
+    }
+    const payload = record.payload;
+    if (!isJsonRecord(payload)) {
+        return "other";
+    }
+    if (record.type === "event_msg" &&
+        payload.type === "user_message" &&
+        isNonEmptyString(payload.message)) {
+        return "user";
+    }
+    if (record.type === "response_item" && isToolCallType(payload.type)) {
+        return "work";
+    }
+    return "other";
+}
+// Responses API tool invocations are persisted as `response_item` rows whose
+// payload type ends in `_call` (`function_call`, `local_shell_call`,
+// `custom_tool_call`, `web_search_call`, ...). Match the whole family so work
+// done through any tool counts, not just plain function calls. Result rows end
+// in `_output`, so they are excluded.
+function isToolCallType(type) {
+    return typeof type === "string" && type.endsWith("_call");
+}

dist/hooks/core/json.js

@@ -10,3 +10,27 @@ export function parseJsonRecord(text) {
         return null;
     }
 }
+// Parse JSONL into records, failing closed: any non-JSON or non-object line
+// yields "unreadable". This is the single chokepoint for turning an untrusted
+// transcript into trusted rows; blank lines are skipped.
+export function parseJsonlRecords(text) {
+    const records = [];
+    for (const line of text.split(/\r?\n/)) {
+        const trimmed = line.trim();
+        if (trimmed === "") {
+            continue;
+        }
+        let parsed;
+        try {
+            parsed = JSON.parse(trimmed);
+        }
+        catch {
+            return "unreadable";
+        }
+        if (!isJsonRecord(parsed)) {
+            return "unreadable";
+        }
+        records.push(parsed);
+    }
+    return records;
+}

dist/hooks/core/run-stop-hook.js

@@ -0,0 +1,8 @@
+import { readFileSync } from "node:fs";
+// Shared stop-hook CLI plumbing: read the host payload from stdin, run a pure
+// evaluator, and emit its JSON result. Keeps host evaluators free of I/O.
+export function runStopHookCli(evaluate) {
+    const stdin = readFileSync(0, "utf8");
+    const output = evaluate({ stdin });
+    process.stdout.write(`${JSON.stringify(output)}\n`);
+}

dist/hooks/core/stop-policy.js

@@ -1,12 +1,10 @@
 import { evaluateAfkGate } from "./afk-gate.js";
-import { summarizeTranscriptFile } from "./transcript.js";
-export function evaluateStopPolicy(input) {
-    const summary = summarizeTranscriptFile(input.transcriptPath);
+export function decideStop(summary, stopTimeMs) {
     if (summary.kind !== "ready") {
         return { kind: "skip" };
     }
     const gate = evaluateAfkGate({
-        stopTimeMs: input.stopTimeMs,
+        stopTimeMs,
         lastUserTimeMs: summary.lastUserTimeMs,
         workHappened: summary.workHappened,
         alreadyShared: summary.alreadyShared,