@rapid-mlx/dsh-provider

A native Rapid-MLX provider for DeepSeek Harness — so dsh gets its model facts from the server instead of from whatever you typed into settings.yaml.

Status: working skeleton, not on npm. Verified end-to-end against dsh 0.1.0-rc.7, and deliberately unpublished (private: true, CI enforces it). DSH is a developer preview that moved rc.6 → rc.7 in days; this repo is here to prove the integration, not to carry a compatibility promise yet.

What it does for you

DSH can already talk to a local Rapid-MLX server through its generic openai-completions provider. That route works — but it knows nothing about your model beyond what you hand-wrote:

# what the generic route makes you maintain, by hand, per model
llm-pi-ai:
  providers:
    rapid-mlx:
      baseURL: http://localhost:8000/v1
      defaultContextWindow: 262144      # you looked this up. is it still right?
      models:
        - id: qwen3.6-35b-8bit
          contextWindow: 262144
          reasoningEfforts: {off: none, low: low, medium: medium, high: high}

Rapid-MLX's /v1/models already publishes all of that and more. This adapter reads it, so:

1. Nothing to hand-write, and nothing to re-write when you switch models. Swap what rapid-mlx serve is running and dsh follows. No re-running setup, no stale numbers.

2. The reasoning control tells the truth. Rapid-MLX reports whether a model actually has a reasoning parser. A model that can't reason no longer shows an off/low/medium/high selector that does nothing.

3. Compaction is timed with the model's real context window, not a number that drifted. This is the one that quietly costs you. dsh-compaction-basic asks the provider for the route's capacity and compacts at thresholdRatio × capacity (0.8 by default). If your hand-written contextWindow is stale or copied from another model, every long session compacts at the wrong point — too early and you lose context you had room for, too late and you hit the wall.

Install

Needs Node ≥ 22.15 (dsh imports Node's Zstd stream API without declaring it) and a running Rapid-MLX server.

# Installs and activates straight from source — no npm publish needed,
# because the package ships plain JS with no build step.
dsh plugin --profile web add github:raullenchai/rapid-mlx-dsh-provider

export RAPID_MLX_BASE_URL=http://localhost:8000/v1     # optional; this is the default
dsh web

Then point the agent at the route:

# $DSH_HOME/settings.yaml
agent-default-model:
  provider: rapid-mlx
  model: qwen3.6-35b-8bit

Verified: that command installs and activates as a profile layer against dsh 0.1.0-rc.7. To hack on it locally instead, see Local development.

Verified

Against dsh 0.1.0-rc.7 on an M3 Ultra:

• Installs and activates as a profile layer (no "declares no dsh.bundle" warning; the entry shows up in dsh --profile headless --dump-config).
• Registers the rapid-mlx route with ctx.llm and serves real queries.
• Plain chat, a single tool call, and the multi-step bug-fix task that gates Rapid-MLX releases — the last one fixed the bug and made the target repo's own test pass, verified independently, in 36 s on qwen3.6-35b-8bit.

Not done yet

Being explicit, because the point of the adapter is to use what the server says and some of it is still only read:

• recommended_sampling — should be applied automatically per model.
• tool_call_parser — should let dsh fail fast on a model that cannot emit tool_calls, instead of looping.
• is_hybrid / is_moe / capabilities — read, not yet acted on.
• Memory-aware capacity. Today resolveModel() reports the model's advertised context window. On a Mac the real ceiling is unified memory, and reporting that instead is the biggest remaining win — it needs Rapid-MLX to expose a usable-capacity figure first.
• Images are not carried through stream() — but they now refuse with LlmError(..., 'UNSUPPORTED') rather than being dropped, per the cookbook. Text, reasoning and tool calls are carried.
• The route is registered as rapid-mlx. If your settings.yaml also declares a rapid-mlx provider under llm-pi-ai, the two compete for one route name (registerAdapter owns provider exclusivity). Use one or rename ours.

Conformance with the official adapter contract

Built against docs/cookbook/adding-an-llm-adapter.md and its "protocol obligations" section. Each item has a test:

Obligation	How it is met
usage before finish, nothing after finish	usage is buffered and flushed at end-of-stream, so a trailing usage-only chunk cannot reorder it
Tool-call arguments are raw JSON strings end to end	fragments stream as argumentsDelta and reassemble unparsed
Block indexes in first-seen order, reused per block	verified across a reasoning-then-text response
Errors take exactly two sanctioned paths	transport/protocol failures throw LlmError with a stable code; nothing ends the stream quietly
Honor options.signal	passed to fetch and to the SSE reader; an AbortError is re-thrown unchanged, not reclassified
A field the provider cannot honor throws UNSUPPORTED	image content refuses instead of being narrowed away
Config is a schemastery schema with env fallback	export const Config, fed from cordis.patch.yml via !!js process.env.RAPID_MLX_BASE_URL

finish.replayState is not emitted: Rapid-MLX needs no native response ids or signatures on follow-up calls, so there is nothing lossless to project.

Three things worth knowing before you edit this

Each of these cost real debugging time:

1. dsh.bundle in package.json is what makes this a plugin. Without it the package installs as an inert dependency and dsh only warns. It is also what gets it appended to the profile's dsh.profile.bundles. CI fails if it goes missing.
2. LlmReasoningEffortInfo.name is required. Returning {id} alone fails the whole model with INVALID_MODEL_REASONING — an error that names the model, not the missing field.
3. DSH has no tool role. Message.role is only system|user|assistant; a tool result is a user-role message whose source.kind === 'tool' carries the callId and whose content holds a ToolResultBlock. Flatten those into plain user text and the model reissues the same call forever — the symptom is an empty answer and a non-zero exit, with nothing on stderr.

Local development

pnpm links a local path outside the profile tree, so Node's parent-walk never reaches $DSH_HOME/profiles/node_modules and the peer deps fail to resolve. Symlink them in — dev only, node_modules is gitignored and excluded from the published files:

mkdir -p node_modules/@deepseek-ai
ln -sfn <dsh-install>/node_modules/@deepseek-ai/dsh-llm node_modules/@deepseek-ai/dsh-llm
ln -sfn <dsh-install>/node_modules/@deepseek-ai/cordis  node_modules/@deepseek-ai/cordis

export DSH_HOME=/tmp/dsh-dev          # never your real ~/.dsh
dsh plugin --profile headless add "$PWD"
export RAPID_MLX_BASE_URL=http://127.0.0.1:8000/v1
dsh --profile headless "say hello"

A real npm install needs none of this: the package lands inside the profile tree, where the flat fallback resolves bare names normally.

When testing agent behaviour, use a strong 8-bit model. A multi-step task here failed on qwen3.5-9b-4bit and passed on qwen3.6-35b-8bit — 4-bit confounds "weak model" with "broken integration".

The engine side guards these fields

Living in its own repo means a rename in Rapid-MLX would break this package silently — nothing there imports it and this CI does not run there. So the fields are pinned on the side that owns them, by tests/test_model_card_client_contract.py in Rapid-MLX, which names this package as its reason. It pins the wire shape: field names, nullability, and the fact that ModelInfo does not set exclude_none — which is what makes "reasoning_parser": null distinguishable from an older server that omits the key entirely.

If you start reading a new /v1/models field here, add it there too. Otherwise the guard silently stops covering what this package actually uses.

License

Apache-2.0, matching Rapid-MLX.