Best possible solution:

Keep the current-main implementation from the merged replacement PR and close this narrower conflicted branch rather than trying to land it separately.

Do we have a high-confidence way to reproduce the issue?

Yes. Source inspection and current regression tests show the reproduction path: custom session:<id> cron delivery must write the delivered assistant message into that same persistent session transcript after successful direct delivery.

Is this the best way to solve the issue?

Yes for current main, not for this branch. The merged replacement is the better solution because it resolves destination sessions, bootstraps outbound session metadata, keeps mirror failure best-effort, and preserves text in mixed media cases.

Security review:

Security review cleared: The PR diff only touches cron delivery code, focused tests, and changelog text; I found no dependency, workflow, secret, package, release, or third-party execution change.

What I checked:

• Current main keeps custom cron deliveries on the custom session: isCustomCronSessionTarget() detects session:<id> targets, and resolveDirectCronDeliverySessionKey() returns the stored agent session key instead of resolving a channel route for those custom-session cron runs. (src/cron/isolated-agent/delivery-dispatch.ts:594, a6aa48350b7e)
• Current main appends the successful direct delivery mirror after full success: After direct delivery succeeds with no partial failure, current main builds a text-first mirror and calls appendDirectCronDeliveryTranscriptMirror() with the resolved delivery session key and idempotency key. (src/cron/isolated-agent/delivery-dispatch.ts:1020, a6aa48350b7e)
• Regression coverage includes the exact custom-session case: The current test keeps custom session cron delivery mirrors on the custom session asserts that outbound context and appendAssistantMessageToSessionTranscript() both target agent:main:session:daily-report. (src/cron/isolated-agent/delivery-dispatch.double-announce.test.ts:1457, a6aa48350b7e)
• Docs define custom cron sessions as persistent context: The cron docs describe session:custom-id as a persistent named session for workflows that build on history, matching the behavior now covered on main. Public docs: docs/automation/cron-jobs.md. (docs/automation/cron-jobs.md:96, a6aa48350b7e)
• Git provenance for the implemented fix: Commit 7de413499f1b068f4f556d8c65753a004cefcd94 added the current-main cron destination-session mirror implementation and related regression coverage; follow-up commits f3403708a3afde367394b6699ecf822059fa2383 and c3a211993cd5933e00745b1d1ab402b8fd30825b tightened classification and awareness policy. (src/cron/isolated-agent/delivery-dispatch.ts:1020, 7de413499f1b)
• Merged replacement PR supplied real behavior proof: Live GitHub data shows fix(cron): mirror announce delivery into destination session #80786 is merged and supplied real WhatsApp cron proof showing a delivered token present once in the resolved destination session transcript. (48b4e5b3614f)

Likely related people:

• cavit99: Authored the merged replacement cron destination-session mirror work that now covers this PR's central behavior on main. (role: implemented current-main replacement; confidence: high; commits: 7de413499f1b, f3403708a3af; files: src/cron/isolated-agent/delivery-dispatch.ts, src/cron/isolated-agent/delivery-dispatch.double-announce.test.ts, src/infra/outbound/outbound-session.ts)
• Peter Steinberger: Authored the follow-up preserving isolated delivery awareness policy and the changelog commit associated with the merged replacement. (role: recent area contributor; confidence: high; commits: c3a211993cd5, 48b4e5b3614f, 741005001b98; files: src/cron/isolated-agent/delivery-dispatch.ts, src/cron/isolated-agent/delivery-dispatch.double-announce.test.ts, CHANGELOG.md)
• kkhomej33-netizen: Introduced session:<id> and current-session cron targeting, which defines the persistent-session behavior this fix preserves. (role: introduced custom cron session behavior; confidence: high; commits: e7d9648fba27; files: docs/automation/cron-jobs.md, src/gateway/server-cron.ts, src/cron/normalize.ts)
• Andy: Worked on delivery mirror dedupe in the transcript append path used by the current implementation. (role: adjacent transcript mirror contributor; confidence: medium; commits: e95efa437381; files: src/config/sessions/transcript.ts)

Codex review notes: model gpt-5.5, reasoning high; reviewed against a6aa48350b7e; fix evidence: commit 7de413499f1b, main fix timestamp 2026-05-15T17:49:30Z.