Best possible solution:

Land the focused Telegram draft-stream fix after maintainer and CI review, keeping one editable partial preview while preserving final overflow delivery.

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

Yes. The current-main source path is clear: an oversized non-final Telegram draft preview can enter the rollover/retain branch before finalization, and the linked issue includes release logs showing repeated preview sends.

Is this the best way to solve the issue?

Yes. The PR fixes the Telegram draft-stream owner path directly, gates rollover to finalization, and keeps final overflow splitting, which matches both the linked issue and the Telegram maintainer streaming note.

AGENTS.md: found and applied where relevant.

Codex review notes: model gpt-5.5, reasoning high; reviewed against a5eddb91bbd8.

Label changes:

• add P1: This PR fixes a linked beta-blocking Telegram partial-streaming failure that can spam visible bot messages during real user turns.
• add proof: sufficient: Contributor real behavior proof is sufficient. The PR body includes after-fix real Telegram bot-to-bot transport proof with the exact command and observed result showing one editable preview plus only a final overflow tail.
• add rating: 🐚 platinum hermit: Overall readiness is 🐚 platinum hermit; proof is 🐚 platinum hermit and patch quality is 🦞 diamond lobster.
• add status: 👀 ready for maintainer look: ClawSweeper has no concrete contributor-facing blocker left for this PR. Sufficient (live_output): The PR body includes after-fix real Telegram bot-to-bot transport proof with the exact command and observed result showing one editable preview plus only a final overflow tail.
• add mantis: telegram-visible-proof: Mantis should capture Telegram visible proof. The PR changes visible Telegram chat streaming behavior, so a short Telegram Desktop proof could directly show one preview being edited instead of multiple preview messages.

Label justifications:

• P1: This PR fixes a linked beta-blocking Telegram partial-streaming failure that can spam visible bot messages during real user turns.
• rating: 🐚 platinum hermit: Overall readiness is 🐚 platinum hermit; proof is 🐚 platinum hermit and patch quality is 🦞 diamond lobster.
• status: 👀 ready for maintainer look: ClawSweeper has no concrete contributor-facing blocker left for this PR. Sufficient (live_output): The PR body includes after-fix real Telegram bot-to-bot transport proof with the exact command and observed result showing one editable preview plus only a final overflow tail.
• proof: sufficient: Contributor real behavior proof is sufficient. The PR body includes after-fix real Telegram bot-to-bot transport proof with the exact command and observed result showing one editable preview plus only a final overflow tail.
• mantis: telegram-visible-proof: Mantis should capture Telegram visible proof. The PR changes visible Telegram chat streaming behavior, so a short Telegram Desktop proof could directly show one preview being edited instead of multiple preview messages.

PR surface:

Source +42, Tests +93. Total +135 across 2 files.

What I checked:

• Repository policy applied: Root AGENTS.md and scoped extensions guidance were read, and the Telegram maintainer note specifically says streaming owns one visible preview message and Telegram behavior PRs need real Telegram proof. (.agents/maintainer-notes/telegram.md:10, a5eddb91bbd8)
• Current main source-reproduces the linked bug path: On current main, oversized rendered preview text enters the rollover path before any final-state gate, resets to a new message, and retains the superseded preview, which matches the linked issue's source-level failure mode. (extensions/telegram/src/draft-stream.ts:206, a5eddb91bbd8)
• PR implementation targets the right boundary: The PR gates overflow rollover to finalization, clamps non-final overflow to the current editable preview, and keeps final overflow state while rotating continuation messages. (extensions/telegram/src/draft-stream.ts:218, 4dc235428594)
• Regression coverage covers clamp and finalization behavior: The PR adds tests for one editable non-final overflow preview, no retained non-final overflow pages, hidden overflow finalization, and multi-chunk final overflow after a clamped preview. (extensions/telegram/src/draft-stream.test.ts:417, 4dc235428594)
• Merge shape is clean against current main: The read-only merge-tree check reported a merged result for the two touched Telegram files, and diff whitespace check returned clean output. (4dc235428594)
• Proof and release state: The PR body reports a real Telegram bot-to-bot group transport run after the patch with one preview message, five edits, and only a final overflow tail; the PR head is not contained in any local release tag yet. (4dc235428594)

Likely related people:

• obviyus: Ayaan Zaidi has multiple prior merged commits in Telegram draft streaming and message-state paths, including restoring partials, hardening streaming state, splitting answer/reasoning draft streams, and stabilizing draft boundary previews. (role: feature-history owner; confidence: high; commits: 37721ebd7ca9, a64d8d2d66ea, ab256b8ec71f; files: extensions/telegram/src/draft-stream.ts, extensions/telegram/src/draft-stream.test.ts, extensions/telegram/src/bot-message-dispatch.ts)
• steipete: Peter Steinberger appears heavily in recent Telegram draft-stream history, including the default partial streaming change and shared draft-stream loop refactors that this code now depends on. (role: recent area contributor; confidence: high; commits: fc1787fd4bea, 3451159174c8, 27ae826f6525; files: extensions/telegram/src/draft-stream.ts, src/channels/draft-stream-controls.ts, src/channels/draft-stream-loop.ts)
• vincentkoc: Current-main blame for the implicated draft-stream overflow block points at Vincent Koc's release-bound commit that added the present draft-stream file snapshot in this checkout. (role: current implementation provenance; confidence: medium; commits: 13dcded7c8e0, a5eddb91bbd8; files: extensions/telegram/src/draft-stream.ts, extensions/telegram/src/draft-stream.test.ts)

• 🦀 challenger crab: rare, exceptional readiness with strong proof, clean implementation, and convincing validation.
• 🦞 diamond lobster: very strong readiness with only minor maintainer review expected.
• 🐚 platinum hermit: good normal PR, likely mergeable with ordinary maintainer review.
• 🦐 gold shrimp: useful signal, but proof or patch confidence is still limited.
• 🦪 silver shellfish: thin signal; proof, validation, or implementation needs work.
• 🧂 unranked krab: not merge-ready because proof is missing/unusable or there are serious correctness or safety concerns.
• 🌊 off-meta tidepool: rating does not apply to this item.

Shiny media proof means a screenshot, video, or linked artifact directly shows the changed behavior. Runtime, network, CSP, and security claims still need visible diagnostics.

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