dsh-plugin-mcp-session-meta

Makes DeepSeek Harness tell MCP servers which conversation is calling.

Every tools/call the harness sends gets the calling Agent's session id in params._meta.session_id. That is the one piece of information an MCP server needs to keep per-conversation state — and the one DSH currently leaves blank.

Chinese documentation: README.zh.md. This is an unofficial community plugin — not affiliated with or endorsed by DeepSeek.

The problem

DSH's MCP client passes { name, arguments } straight through as the request params, leaving _meta empty:

call: (args, execution) => client.callTool({ name: tool.name, arguments: args }, { … })

But _meta is a first-class optional field of MCP's BaseRequestParamsSchema:

const BaseRequestParamsSchema = z.object({ _meta: RequestMetaSchema.optional() })

So a server can only ever see the process, never the conversation. For a server whose state is per-conversation — browser automation with tab groups, editors, anything with sessions — every conversation in the harness shares one bucket and the server has no way to tell them apart.

Other MCP clients already send it: ZCode sends session_id, Antigravity sends antigravity.google/conversation_id, Codex sends thread_id, WorkBuddy sends workbuddy.ai/conversationId. DSH is the odd one out.

The identity is already sitting at the call site — the agent loop sets ToolExecutionInput.agent ("The agent on whose behalf the call runs"), and agent.id is the SessionId. It is simply not forwarded.

What it changes

Two patches, both in the derived artifact:

Patch	Before	After
clientInfo	{ name: "dsh-mcp-client", version: "0.0.1" } — a middleware self-report with a placeholder version	{ name, title: "DeepSeek Harness", version: "<real>" }
tools/call params	{ name, arguments }	{ name, arguments, _meta: { session_id: <agent.id> } }

_meta is omitted entirely when there is no Agent on the execution (nested dispatches) — a missing key means "this frame doesn't know", which is different from claiming a session.

Install

The artifact has to be regenerated against your installed DSH, because the patch targets DeepSeek's compiled bundle and that changes between releases.

git clone https://github.com/Liang-HZ/dsh-plugin-mcp-session-meta
cd dsh-plugin-mcp-session-meta

node sync.mjs                  # extract from your app.asar + patch (fails loudly if the anchors moved)
node install.mjs --list        # show the MCP entries in your profile
node install.mjs --server NAME # point that one entry at this package

Then restart DSH — see Caching below.

• --profile web — target another profile (default desktop)
• --check — report only, change nothing
• --uninstall — put the entry back to the upstream package

Only the entry you name is switched; other MCP servers keep using the upstream client. Nothing else in the harness changes.

Caching: a restart is required

DSH caches imported plugin modules. Editing plugin code — or even changing which package an entry points at — does not take effect live: Node's ESM cache is keyed by URL, and the plugin manager's enable/disable only re-runs apply() on the already-imported module. A restart (or a brand-new entry id) is the only thing that re-imports. Expect "the entry is active, the module name changed, and it still runs the old code" until you restart.

Compatibility

• Built and tested against @deepseek-ai/dsh-mcp-client 0.2.0-rc.2 (DeepSeek Harness 0.2.0-rc.2, macOS).
• sync.mjs asserts on both patch anchors. If a DSH upgrade moves them it fails rather than emitting an unpatched artifact — a silently unpatched copy is the worst outcome here, because the plugin would still load and simply stop doing anything.
• Node ≥ 22.15 (extraction uses zlib.zstdDecompressSync).

How it is built (and why not a plain fork)

DeepSeek's harness repository does not accept external pull requests, and the app bundle is code-signed with per-file integrity hashes — editing files inside app.asar breaks the signature and is overwritten by every update.

So the artifact is extracted, patched and regenerable rather than a frozen copy:

node sync.mjs          # regenerate lib/index.js from the installed app
node sync.mjs --check  # is the artifact still what this DSH would generate?

sync.mjs also reads the external modules the bundle imports and writes them into peerDependencies. That is not bookkeeping: DSH's profile resolver supplies packages by peer declaration ("Linked importers apply current peer declarations at each ancestor node_modules"). An undeclared peer is not supplied, and the plugin dies during import with no useful error. Deriving the list from the artifact keeps it in step automatically.

Notes for other DSH plugin authors

Two things that cost real time to discover:

1. Declare every package you import as a peerDependency. The resolver in @deepseek-ai/dsh-app-boot reads the importing package's own manifest to decide what to supply. Miss one and the fiber ends up DISPOSED with a bare fiber state 4 and no message.
2. patchReload: "live" is a profile setting. The shipped web profile has it; a profile without it will not pick up patch edits without a restart.

When to delete this

When DSH forwards the session id itself. The upstream fix is small — the identity is already in scope at the call site — and this plugin exists only to fill the gap in the meantime.

That request is filed here, with the exact change and the evidence: https://github.com/deepseek-ai/deepseek-harness/discussions/9519

If it lands, this package is dead weight — uninstall it.

License

MIT. The derived lib/index.js is a patched build of @deepseek-ai/dsh-mcp-client (MIT, © DeepSeek). See NOTICE.