@amaster.ai/dsh-langfuse

Langfuse observability for DeepSeek Harness (dsh):

• one generation per LLM call (llm/stream waterfall), plus a nested llm-request span carrying the verbatim loop-built request
• one span per tool call (tools/execute waterfall)
• one trace per session turn (session/event) — in the v5 SDK the trace IS its root span, ended (and thereby exported) at turn/end
• subagent child sessions nested under the parent's tree (session/created header link + subagent/start / subagent/end)

Install

dsh plugin --profile my-agent add @amaster.ai/dsh-langfuse \
  @langfuse/tracing @langfuse/otel @opentelemetry/sdk-trace-node \
  @opentelemetry/api @opentelemetry/exporter-trace-otlp-http

The Langfuse JS SDK v5 peers (@langfuse/tracing, @langfuse/otel, @opentelemetry/sdk-trace-node) are loaded via lazy dynamic import(), so an unused install costs nothing — but they must all be present at runtime (dsh plugin add does not auto-install peer trees, so the OTEL api/exporter packages @langfuse/otel itself peers on are listed explicitly).

Configuration

Disabled by default. Configure via the profile's cordis.patch.yml:

- insert:
    - id: langfuse
      name: '@amaster.ai/dsh-langfuse'
      config:
        enabled: true
        publicKey: pk-lf-...
        secretKey: sk-lf-...            # secret role
        baseUrl: https://cloud.langfuse.com
        traceName: dsh-turn
        captureContent: true            # set false to record metadata only

Buffered spans drain on session/flush(session); the exporter shuts down with the plugin fiber.

Observability is a no-throw seam: backend errors are logged with a [dsh-langfuse] prefix and never escape into the agent loop.

Compatibility

Pinned dsh/cordis versions live in the root compat matrix. Event payloads ride pre-release dsh APIs — check the TODO(verify) markers in src/ before upgrading dsh.

License

MIT