Label unnamed shared-session participants

[OmarB97]

Summary

• add a shared-session participant label helper that preserves display names when present and falls back to a stable redacted sender label when no display name is available
• sanitize user-controlled display labels before they are placed in [label] prefixes so aliases stay single-line and bracket-safe
• prefix inbound shared multi-user session messages with that sender label so multiple unnamed humans/devices remain distinguishable without leaking raw opaque IDs
• update the shared-session context prompt from [sender name] to [sender label]
• add a session event fanout harness proving a primary transport and sidecar listener receive the same JSON-RPC session event frame
• map omar@kostudios.io in scripts/release.py so contributor attribution CI can resolve the PR author

Verification

• python3 -m pytest tests/gateway/test_shared_group_sender_prefix.py tests/gateway/test_session.py tests/tui_gateway/test_protocol.py -q (144 passed)
• python3 -m compileall -q scripts/release.py gateway/session.py gateway/run.py tests/gateway/test_shared_group_sender_prefix.py tests/tui_gateway/test_protocol.py
• uv tool run ruff check scripts/release.py gateway/session.py gateway/run.py tests/gateway/test_shared_group_sender_prefix.py tests/gateway/test_session.py tests/tui_gateway/test_protocol.py
• git diff --check
• git diff upstream/main -- gateway/session.py gateway/run.py tests/gateway/test_shared_group_sender_prefix.py tests/gateway/test_session.py tests/tui_gateway/test_protocol.py scripts/release.py | rg -n "discord|Discord|telegram|Telegram" (no matches)
• portable local attribution-map emulation for PR author emails (passed)

Risk

The behavior change is limited to shared multi-user sessions. Per-user isolated sessions keep their existing plain inbound message behavior, and raw sender IDs are not exposed in the fallback label. Display aliases are preserved after whitespace/bracket normalization.

[liuhao1024]

Verified clean — shared session participant labeling

Reviewed the diff across gateway/session.py, gateway/run.py, and tests:

1. Bracket injection prevention: _sanitize_participant_label replaces [/] with (/) and truncates to 64 chars. This prevents user-controlled display names from breaking the [label] message prefix format.

2. Stable fallback: When no display name exists, shared_participant_label falls back to _hash_sender_id(raw) which produces a deterministic user_XXXXXXXX label. Different user_id values produce different labels (verified by test_shared_participant_labels_distinguish_multiple_unnamed_senders).

3. Priority chain: user_name → user_id_alt → user_id → None. The user_id_alt check before user_id handles platforms that provide an opaque internal ID alongside a human-readable one.

4. No behavioral regression: The prefix format change from [sender name] to [sender label] is cosmetic in the session context prompt — tests updated to match.

No findings.

[OmarB97]

Thanks for the thorough verification @liuhao1024 — that write-up matches the implementation exactly, and I appreciate the injection-prevention check in particular.

Re-confirmed today (2026-07-11) at the current head (c55ce3d4): _sanitize_participant_label still collapses whitespace, swaps brackets for parens, and caps at 64 chars (gateway/session.py:57); the fallback chain in shared_participant_label is display name → user_id_alt → user_id → None with the deterministic user_<hash> label (gateway/session.py:165). I also checked that current upstream main still has none of this labeling, so the PR is not superseded — it remains mergeable as-is against today's main.

Ready for a maintainer merge whenever it fits.

[teknium1]

Thanks for addressing the real unnamed-participant gap: current main only prefixes a shared turn when source.user_name is present (gateway/run.py:10388-10389).

Problems

• The new fallback at gateway/run.py:7627 also applies to Yuanbao group turns. Yuanbao builds a source with user_id and thread_id="main" (gateway/platforms/yuanbao.py:2010-2016), then deliberately preformats the message as [nickname|user_id] and clears only user_name to suppress the runner prefix (gateway/platforms/yuanbao.py:2160-2164). The fallback will therefore add [user_<hash>] before that existing label.

Suggested changes

• Preserve an explicit no-second-prefix signal for already-attributed adapter messages while retaining the opaque-ID fallback for ordinary shared turns.
• Add a Yuanbao group/thread regression proving the message remains singly attributed.

Automated hermes-sweeper review.

[teknium1]

This fallback also defeats Yuanbao's intentional suppression: its group middleware preformats [nickname|user_id] and clears only source.user_name to prevent the runner prefix (gateway/platforms/yuanbao.py:2160-2164), while retaining user_id. This will now produce [user_<hash>] [nickname|user_id] ...; preserve an explicit already-attributed/no-prefix path and add a regression.