PR #24147 - manaflow-ai/cmux

Summary

Follow-up to #23962. Leo saw a sent-message card in claude-sr2's chat that read "✓ Sent", but its SendMessage result was success:false ("was stopped by the user and won't be resumed"). The card was lying.

Before #23962, main's MessageCard looked only at the tool status. A completed call with a success:false result read as Sent. #23962 changed that to one word, "Failed", with no reason. This PR says why, in a muted warning tone at the line's end, and never shows the raw result:

Not delivered: agent stopped: the result says the agent was stopped, won't be resumed, isn't running or has exited.
Not delivered: no such agent: no agent or session by that name (also matches no_session, "not found" and "unknown agent").
Not delivered: any other failure, including a result that says it "could not be delivered" or "failed to deliver". Those used to match "delivered".

Also from #23962's review notes:

An empty error field is not an error.
The agentId is now the last agentId: in an Agent call's result, so a subagent report that mentions another id can't win.
A nested subagent's agentId is captured too.
The opened message's fade follows a resize.
The catalog keys the sent row no longer uses are gone (message.delivered, message.sending, message.channel.*).
The transcript gallery note is updated.

The shared AgentMessageRow API is unchanged.

Gallery

The new outcomes state on agent-pane.agent-message-row is a synthetic coordinator chat:

one SendMessage delivered to "Fix grid jump";
one to a stopped "Time-cap pre-push owner check", which reads "Not delivered: agent stopped";
a "Received message from grid-lane" row.

Before/after: https://cmux-lawrences-mac-mini.tail137216.ts.net:18796/compare/tp-sent-card-real-outcome/?entry=agent-pane.agent-message-row

Tests

webviews/test/transcript-row-message.test.tsx: three synthetic success:false results (stopped, no such agent, no reason) show their own words, and none of the result's text shows, closed or opened.
agentMessages.test.ts:
- notDeliveredReason for JSON and plain-text results;
- "could not be delivered", "not delivered" and "failed to deliver" never read as delivered;
- an empty error field is no error.
subagentFold.test.ts: the last agentId: wins.

Observed / Not run

Observed: scripts/web-lint.sh passed. For #23962, a fleet run of these three test files passed at its head.
Not run locally: bun tests (this Mac's hook sends them to the fleet). The fleet run for this head is linked in a comment.

Changelog

Fixed: a message to an agent that was stopped, or doesn't exist, no longer reads "Sent". Its line says "Not delivered" and why.

Risk: risk:normal (webview UI only).

Leo-ask: ask-0033ce890a

Agent session: cosmic-gray

🤖 Generated with Claude Code

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Summary by cubic

Fixes the agent pane so a sent message that never arrived no longer reads "✓ Sent" — its line now says "Not delivered" and why, in a muted warning tone, and never shows the raw result.

A stopped agent reads "Not delivered: agent stopped"; no matching agent reads "Not delivered: no such agent"; any other failure reads "Not delivered".
Results saying "could not be delivered", "not delivered", "failed to deliver", or "wasn't delivered" are treated as failed, never delivered; a recipient's name can't trigger a failure word.
A mailbox write that echoes the message it wrote still reads as Sent, and only whole echoed lines and a recipient's name are cut from a receipt, so a short message like "not" never erases the receipt's words; a message saying "success" or "ok" can't erase a JSON receipt's failure flag.
An empty error field is no longer treated as an error.
The agentId taken from an Agent call's result is the last one it names, and nested subagent ids are captured too.
The opened message's fade now follows a resize, and the now-unused catalog keys were removed.