[qingyun-wu]

Stacked on #3095 (feat/discord-delivery-provider). Merge order: #3091 → #3092 → #3094 → #3095 → this. Child-only layer: pr3095..HEAD, 3 files, +187/−6.

What

Stage 1 of migrating poll_proactive behind the delivery-core seam: the text send-leg only. The bridge keeps claim/retry orchestration — the proactive-*.txt .sending claim protocol is shared by the discord/telegram/slack bridges on the same files, so moving claiming requires a cross-bridge migration fence (single-protocol-per-epoch); that is deliberately out of this PR. Attachments stay on the WS client (the provider has no file surface yet).

• src/discord_proactive_send.py — deliver_text(provider, channel_id, text, item_id, chunker): per-chunk delivery through DiscordDeliveryProvider, per-chunk idempotency keys ({item}#{i}).
• Receipt → exception mapping, chosen to make duplicate sends structurally hard:
  • OUTCOME_UNKNOWN → send_failure_policy.UnconfirmedDelivery — the policy's capped-transient class (bounded retry visible to the bridge's attempt budget, then park). This replaces the old WS behavior where a timeout looked like a plain failure and was retried on the next poll — the 2026-08-16 12-duplicate incident's shape.
  • NOT_DELIVERED → ProviderSendFailed, permanent (a 4xx does not become a 200), carrying sent_chunks so the bridge's progressed signal survives partial sends.
• poll_proactive wiring: DM leg and [channel:] redirect leg both deliver text via asyncio.to_thread(deliver_text, ...); the redirect's fail-loudly semantics (literal marker kept in DM + WARN on failure) are unchanged — a provider failure raises into the existing except path.

Evidence

At HEAD:

$ python3 tests/discord-proactive-send.test.py
PASS: proactive send-leg — ordered confirmed chunks, capped-transient UNKNOWN, permanent refusal with progress
$ python3 tests/discord-delivery-provider.test.py   # unchanged sibling
PASS: DiscordDeliveryProvider — contract receipts, raising config errors, real core+backend wiring
$ bash scripts/review-checks.sh --diff <(git diff pr3095..HEAD)
review-checks: PASS (hardcoded-paths + root-artifacts + prose-cap clean)
$ bash scripts/lint-workspace-resolution.sh --diff
✓ no new workspace-resolution anti-patterns in this diff.

Before (parent): poll_proactive sent text via await dm.send(chunk) / await _target_ch.send(chunk) (WS client, no receipts, timeout = retry-next-poll). After: chunks earn canonical CONFIRMED / NOT_DELIVERED / OUTCOME_UNKNOWN receipts with the mapping above.

Live-path status

This is the live proactive delivery loop, so harness proof is not sufficient for merge-readiness per repo policy. The live round trip (bridge restart on this branch → synthetic proactive-*.txt → message observed in the owner DM, including one UNKNOWN injection) is planned as part of the stack's post-merge restart chain, same protocol as #3086's done-chain; happy to run it pre-merge on request instead.

Signed: @sutando-qingyun-001:ag2.space

🤖 Generated with Claude Code

[qingyun-wu]

Folded into #3095 at the owner's direction — the provider and its first activated caller (the proactive text send-leg) now review as one unit, which is what both review threads asked to see. Branch feat/discord-proactive-provider is superseded.