RFC: Collaborative multi-participant task sessions

## Primary area

** Cross-cutting / multiple

## Related issue or feature request

_Related: **feature-ide-workspace-context-sync.md**, roadmap **Multi-user nudge**._

## Summary

Explore **multi-participant sessions** where more than one human (or role: PM, engineer, reviewer) can observe and contribute to the same in-flight task context—shared timeline, permissions, and handoff—rather than only single-submitter fire-and-forget.

## Use case and motivation

Background agents are moving from private laptop sessions to **durable cloud objects** teams collaborate around. Use cases: PM starts exploration, engineer takes over; legal/ethics wall boundaries per participant; shared validation before PR.

## Proposal

### Phase 0 (read-heavy)

- Task `participants[]` with roles; all see same `TaskEvents` stream and **Smart progress updates**.
- **Multi-user nudge** (roadmap) as write path.

### Phase 1 (shared session object)

- Session entity linked to `task_id` with join tokens, per-user visibility rules (repo + path ACL).
- Optional live attach to same MicroVM (operator-only pilot).

## Out of scope

- Full collaborative IDE product.
- Replacing GitHub PR review workflow.

## Potential challenges

- AuthZ complexity, data walls between teams, session cost while multiple users attached.
- AgentCore session model may not support multi-attach—may be events-only in v1.

## Dependencies and integrations

- Cognito identities, Cedar policies, `INTERACTIVE_AGENTS.md`, channels

## Alternative solutions

- **Context sync API only**—lighter weight; see separate feature draft.

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**Note:** Non-triaged RFCs may not get timely review. PRs on non-triaged issues might not be accepted.

* RFC PR:
* Approved by:
* Reviewed by:

Inizia leggendo feature-ide-workspace-context-sync.md e INTERACTIVE_AGENTS.md, quindi esamina le dipendenze di Cognito identities, Cedar policies e channels elencate qui. Questo RFC è completato quando l'ambito di sessione supportato, le autorizzazioni dei partecipanti e le priorità delle fasi sono stati esaminati e decisi.

Scritto dal modello di indicizzazione a partire dal testo della issue.