feat(codex): read Codex's own background-terminal row

Codex states background work too, and it says so in a different place. Claude
writes `· 1 monitor ·` on the last row of the screen; Codex pins
`1 background terminal running · /ps to view · /stop to close` ABOVE its
composer, which puts that row third from the bottom once the status line and
the composer are counted.

So how far up the screen to look is now per-CLI data as well:
`capabilities.workDetect.watchingLines`, bounded to 1..8 by the schema, and
defaulting to Claude's two. That bound is the point. The window is half the
injection guard, since every row it adds is another row the agent itself may be
able to write, and the label is what silences an idle alert. The other half is
the anchor, and Codex's is ` · /ps to view`: chrome naming a slash command only
the CLI can offer, so a session that writes "I left 1 background terminal
running for you" into its own output matches nothing.

Measured against a live codex-cli 0.154.0 pane rather than read out of a
binary. The row appears when the terminal starts, follows the composer down as
the conversation grows, and is gone after `/stop`. Verified end to end on an
isolated beta: the session payload carried `watching: "1 background terminal"`
and the badge rendered with it, and both cleared when the terminal stopped. The
fixtures in the tests are that capture verbatim.

Codex has no hook signals, so no idle prompt and no false NEEDS YOU row: for a
Codex session this is the badge alone, which is the case the maintainer said a
registry field could cover and a hook never could. Cross-CLI tests pin that
neither pattern fires on the other's screen, and that a CLI declaring nothing
still reports nothing.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/config/cli-registry/schema.ts

@@ -318,6 +318,9 @@ const capabilitiesSchema = z
             'watchingLine must be a regex compileVersionRegex() accepts: at most 200 characters, no nested quantifiers'
           )
           .optional(),
+        // Bounded hard: this is how far up the screen a config file may push the search,
+        // and every row it adds is one more row the agent itself may be able to write.
+        watchingLines: z.number().int().min(1).max(8).optional(),
       })
       .strict()
       .optional(),

src/config/cli-registry/stock.ts

@@ -530,7 +530,21 @@ const CODEX: CliEntry = {
     // `Working (2m 49s • esc to interrupt)` above it while a turn runs. It animates no
     // braille spinner, and it never prints `esc to interrupt` at rest, so that phrase
     // alone separates a running turn from an idle one.
-    workDetect: { promptGlyph: '›', workingLine: '[Ee]sc to interrupt' },
+    // Codex pins a row of its own while a background terminal it started is still
+    // running: `  1 background terminal running · /ps to view · /stop to close`. Unlike
+    // Claude's footer chip that row sits ABOVE the composer, which puts it third from the
+    // bottom once the status line and the composer are counted, hence `watchingLines`.
+    // The ` · /ps to view` tail is the anchor: it is CLI chrome, it names a slash command
+    // that only the CLI can offer, and without it a bare count in the transcript would do.
+    // Measured against a live codex-cli 0.154.0 pane on 2026-09-22: the row appears when
+    // the terminal starts, follows the composer down as the conversation grows, and is
+    // gone after `/stop`.
+    workDetect: {
+      promptGlyph: '›',
+      workingLine: '[Ee]sc to interrupt',
+      watchingLine: String.raw`(\d+ background terminals?) running · /ps to view`,
+      watchingLines: 4,
+    },
     transcript: 'codex-rollout',
     altScreen: 'strip-full',
     echo: { policy: 'predict', anchor: { kind: 'cursor' }, predictProfile: 'codex' },

src/config/cli-registry/types.ts

@@ -345,13 +345,23 @@ export interface CliCapabilities {
     /** Source of a regex matching the status line this CLI draws while a turn runs. */
     workingLine: string;
     /**
-     * Source of a regex matching the chip this CLI draws at the foot of its screen while
-     * work it started in the background is still running, e.g. Claude's `· 1 monitor ·`.
-     * Capture group 1 is the label Codeman shows, and the whole match stands in when the
-     * pattern declares no group. A CLI that omits this reports no background work, which
-     * is what every CLI did before the field existed.
+     * Source of a regex matching the row this CLI draws while work it started in the
+     * background is still running, e.g. Claude's `· 1 monitor ·` footer chip or Codex's
+     * `1 background terminal running · /ps to view`. Capture group 1 is the label Codeman
+     * shows, and the whole match stands in when the pattern declares no group. A CLI that
+     * omits this reports no background work, which is what every CLI did before the field
+     * existed.
      */
     watchingLine?: string;
+    /**
+     * How many rows at the FOOT of the screen that row can appear in, counting non-blank
+     * rows only. Claude writes its chip on the last row and keeps the default; Codex pins
+     * its own above the composer, which puts it third from the bottom, so it declares
+     * more. Keep each number as small as that CLI's layout allows: every extra row is
+     * another row an agent might be able to write, and the label is what silences an
+     * alert. See `watchingLabel()` in `session-activity.ts`.
+     */
+    watchingLines?: number;
   };
   /** No direct-PTY fallback: the CLI must run inside tmux (secrets ride tmux setenv). */
   requiresMux: boolean;