[Unofficial] dsh-cross-session-agent: safe coordination across Harness sessions

[dd2673]

Unofficial third-party plugin. This project is not affiliated with, reviewed by, endorsed by, or supported by DeepSeek or DeepSeek Harness.

What it is

dsh-cross-session-agent helps independent Harness sessions coordinate when multiple agents are working in the same repository. It is designed for file-ownership coordination, blocker/handoff reports, avoiding duplicate work, and checking limited progress evidence before sending a deliberate peer message.

It contributes four tools:

• list_peer_agents: discover eligible peer sessions and runtime metadata
• send_agent_message: send one explicit coordination message
• check_delivery: inspect native transport receipts without claiming read/reply/completion
• get_peer_context: read a bounded, same-cwd context/activity projection

Privacy and trust boundary

get_peer_context does not expose an arbitrary transcript or search API. It allows only a different, unarchived, non-subagent Session with the exact same non-empty cwd.

Conversation output contains only the folded current surface: direct user text, canonical compaction checkpoints, and completed assistant text. Activity contains structural turn/step state plus tool name/status/time, a one-way call-id fingerprint, and sanitized error code. Hidden reasoning, raw tool inputs/results/meta, system prompts, plugin/relay/scheduled messages, approvals, inbox data, attachments, todos, credentials, unknown events, and shadowed history are excluded.

Peer text is always untrusted background data. It cannot grant permissions, replace user approval, change configuration, or prove that work completed. The plugin has no network calls, telemetry, independent database, or parallel transcript store; Harness remains the data owner.

This boundary follows the same isolation principle used by official cross-session/subagent designs: explicit messages and bounded final/current projections, not implicit sharing of private histories or tool traces.

Install and compatibility

dsh plugin --profile web add github:dd2673/dsh-cross-session-agent

Current release: v0.1.0, tested against DeepSeek Harness 0.1.0-rc.6 on Node 24.

Validation performed:

• source tests: 46/46
• package allowlist and pnpm pack --dry-run
• packed-plugin live rc.6 profile E2E
• same-workspace conversation + structural activity read
• cross-workspace authorization fail-closed
• native relay persistence with the new source/tag
• manual static scan: no runtime network, telemetry, environment-secret reads, or independent file persistence

Security/privacy details: SECURITY.md, PRIVACY.md, architecture.

The project is MIT and independently maintained. It derives from GengDaPeng/dsh-agent-message v1.5.1 under MIT; attribution is retained in NOTICE.md.