Same-runtime cross-Session discovery and communication for DeepSeek Harness
The plugin will be installed here. Keep web if you are unsure.
npx -y @deepseek-ai/dsh plugin --profile web add @wha1echai/dsh-cross-session@0.1.0-rc.1
Compatibility and provenance
Cross Session is published as @wha1echai/dsh-cross-session and currently resolves to version 0.1.0-rc.1. The Hub verifies its manifest and preserves the exact installation source for reproducible installs.
A community plugin for DeepSeek Harness focused on cross-Session discovery, addressing, and communication among live Sessions in the same running DSH runtime (one dsh process). It exposes a replaceable ctx.fleet service plus model-callable fleet_* tools over that service.
Status: 0.1.0-rc.1 prerelease, tool preview (L0 + L1 + L2 + L2.1 + L2.2 + L2.3 + L2.4 + L2.5). Fleet now includes optional log-backed title projection, lossless inspect truncation facts, attributed confirmed-target relays, and exact claimed-turn reply observation. The Fleet service, authoritative runtime-ownership classification, five core tool definitions, and optional Jobs Consumer are implemented and keylessly tested through the built package entries. The current product surface is an API and model tools, not a multi-Session UI or remote control service. The prerelease uses the next dist-tag and is not a stable compatibility promise.
This is an independent community project and is not affiliated with or endorsed by DeepSeek AI. It runs inside the existing DSH process and does not start a daemon, a second agent runtime, or a separate network port.
Design
DeepSeek Harness treats capabilities as hot-swappable plugin seams. dsh-cross-session follows the same structure:
FleetService Service Definition (`ctx.fleet`)
InProcessFleetProvider Same-process Provider (`ctx.agents`)
fleet_* tools Current Consumer (`ctx.fleet` + `ctx.tools`)
supervisor preset Planned Consumer (L3)
profile / surface / transport Future Consumers (L4+)
The Fleet tool Consumer never imports the Agent or Subagent APIs and does not access ctx.agents, ctx.sessions, or ctx.subagents. It registers only fleet_* tools. The plugin does not replace or duplicate the existing subagent or workflow capabilities:
delegated-Session continuation and interruption belong to the public ctx.subagents seam and its official Consumer;
orchestration belongs to the public ctx.workflowEngine seam and its official Consumer;
Fleet adds a same-process view of live Sessions and limited root-Session control.
Subagent and workflow tools are optional profile composition. They are model-visible only when their corresponding public seam and Consumer are mounted; Fleet does not advertise unavailable capabilities.
Confirmed-target model fleet_send / fleet_steer use a versioned fleet-relay source. The exact caller Agent supplies senderSessionId; the Provider supplies an opaque deliveryId. The model-visible header encodes both values; the body starts after a fixed marker in a separate text block, is preserved as untrusted model input, and cannot override structured attribution.
The separate @wha1echai/dsh-cross-session/tool entry registers:
fleet_list and fleet_inspect in every mode;
fleet_send and fleet_steer in message and full modes;
fleet_cancel only in full mode.
Mounting this Consumer makes its currently configured tools available to already-live Sessions through normal ToolRuntime composition on their next model request. It does not inject a synthetic chat message or rely on permanent system-prompt prose to announce Fleet.
The direct Service API keeps sessionId as the stable routing identifier for trusted programmatic Consumers. Selected steer receipts include an opaque deliveryId; selected send also returns a caller-bound single-observer replyReceipt. Delivery still means inbox acceptance only. waitForReply() later observes the complete turn that claims that exact message without using Agent idle as proof or claiming strict message-to-message causality. Model tools use a confirmed-target protocol instead: fleet_list returns a caller-bound targetRef, fleet_inspect accepts that reference and may issue an exact-Agent-bound single-attempt selectionHandle, and write tools accept only the selection. Invalid, expired, mismatched, replaced, unloaded, or already-used handles fail closed and never authorize substituting another Session. Every Agent view still includes sessionId; any future Session-list UI must display it and provide a copy action.
The default controlMode is read-only. All five confirmed-target tools pass the exact owning Agent object and derive its Session id for Provider cross-checking; model fields cannot supply caller identity, and agentless execution is rejected. Write authorization remains in ctx.fleet. Fleet classifies runtime roots by exact Agent membership in ctx.agents.roots(); durable origin and parentSession metadata do not affect kind or write authority. Delegated Agents remain read-only in L2.1; the Consumer never bypasses Fleet to call subagent APIs directly.
The optional @wha1echai/dsh-cross-session/reply-job entry registers fleet_wait only when ctx.jobs is mounted. It starts an owner-scoped fleet-reply background job; official job tools remain responsible for output, list, kill, controller, and completion notices. Killing the job aborts only reply observation and does not cancel the target. Mount this Consumer in the same host or agent-preset composition as the official Jobs Consumer; its scoped ToolRuntime registration then follows that composition.
When the optional sessionTitle service is mounted, Fleet reads only an already logged title from the exact live Session and exposes it as a display field in list/inspect projections. Missing or unloaded title service leaves Fleet available without title; title never affects identity, routing, selection, ordering, filtering, or authorization. Inspect separately reports messages omitted by the tail limit and per-message textTruncated facts.
The in-process Provider sees live Sessions only in the same running DSH runtime, meaning the same dsh process. The current release does not provide:
cross-process or multi-runtime discovery and control;
cross-terminal or cross-device routing;
local-to-server control;
remote Web, gateway, or daemon support;
a multi-Session Web or desktop UI.
The web profile used below is an existing DSH host for installation and development. It does not mean that this plugin supplies remote Web support or a supervisor UI. Web may become a future first-class surface, with Electron as an optional wrapper, but both remain secondary to same-runtime communication.
Requirements
Node.js ^22.19.0 or >=24.0.0
pnpm 11.7.0 for repository development
@deepseek-ai/dsh@0.1.0-rc.6
The first release line intentionally makes no compatibility promise across DSH release candidates.
Install
Install the first prerelease by exact version or through the next dist-tag. A bare package install selects npm's latest tag and is not a prerelease install.
dsh plugin --profile web add @wha1echai/dsh-cross-session@0.1.0-rc.1
dsh --profile web --dump-config
Use an isolated DSH_HOME when evaluating the package without changing an existing profile. Local checkout and commit-pinned GitHub installations remain available below.
Local checkout
git clone https://github.com/Wha1eChai/dsh-cross-session.git
cd dsh-cross-session
pnpm install
pnpm run build
dsh plugin --profile web add /absolute/path/to/dsh-cross-session
dsh --profile web --dump-config
dsh --profile web
On PowerShell, use an isolated development home instead of changing an existing user profile:
$env:DSH_HOME = "D:\coding\programs\dsh\.dsh-cross-session-home"
dsh plugin --profile web add D:\coding\programs\dsh\dsh-cross-session
dsh --profile web --dump-config
dsh --profile web
GitHub source
Pin a reviewed commit:
dsh plugin --profile web add github:Wha1eChai/dsh-cross-session#<commit>
Git installs run the package's prepare script to build TypeScript. pnpm 10 and later reject that script until the user explicitly allows the package in the profile's pnpm-workspace.yaml:
allowBuilds:
'@wha1echai/dsh-cross-session': true
Review the source and pin a commit before granting install-time execution permission. Re-run dsh plugin add after adding the allowance.
Usage
The Bundle installs the host-plane Fleet Provider and the core tool Consumer at its safe read-only default, exposing fleet_list and fleet_inspect. It does not install the optional reply-job Consumer. Mount @wha1echai/dsh-cross-session/reply-job in the same host or agent-preset composition as the official Jobs Consumer when fleet_wait is intended; scoped ToolRuntime registration keeps that optional tool inside the selected composition.
To enable message or cancellation tools, override the complete dsh-cross-session-tools row in the profile's cordis.patch.yml:
fleet_wait can consume only a reply receipt returned by enabled fleet_send; starting its job also requires an official Jobs controller Consumer in the owner's composition. Use full only in a composition where model access to cancellation is intended. controlMode selects tool visibility; it does not replace tools/pre-execute, approval, or ctx.tools.guard() policy.
Other plugins may consume Fleet directly by declaring fleet as a required service:
export const inject = ['fleet']
export function apply(ctx: Context) {
const live = ctx.fleet.list()
// Build a future command or UI adapter from the same-runtime JSON-safe view.
}
Such Consumers are separate plugins and are not included with the current package. Any future transport or remote Consumer also requires separate identity, transport, and permission design; the current sessionId must not be treated as a global remote address.
Development
pnpm install
pnpm run typecheck
pnpm test
pnpm run build
pnpm pack
The tests use the real ToolRuntime, validate canonical values and model-facing content, and boot a test-only cordis.yml through the official Loader + Include path using the built Provider, tool, and reply-job entries. They also guard all namespace entries against a default export and verify Provider/Consumer unload behavior. The packed-artifact gate checks tarball contents, declarations, Loader namespace unwrapping, and package self-reference metadata:
pnpm pack --pack-destination .pack-output/dev
pnpm run check:packed -- .pack-output/dev
Roadmap / TODO
L0 — installable Bundle, build, package metadata, real Loader smoke.
Bug reports, design feedback, and narrowly scoped pull requests are welcome through this repository. Preserve the capability-seam design: Consumers depend on ctx.fleet, delegated writes go through a future Fleet API backed by ctx.subagents, orchestration stays in ctx.workflowEngine, and model-visible capability follows the seams and Consumers actually mounted in the profile. See CONTRIBUTING.md, SECURITY.md, and release and rollback.
