deepseek-harness/packages/llm/llm-deepseek

description, kind

description	kind
The DeepSeek chat-completions adapter for users and maintainers configuring the deepseek-official route, thinking, and image input.	package-reference

@deepseek-ai/dsh-llm-deepseek

English | 中文

Summary

@deepseek-ai/dsh-llm-deepseek is the direct DeepSeek adapter for the harness LLM service: it owns the deepseek-official provider route and translates DeepSeek's chat-completions wire format into the harness stream-chunk protocol. With it a composition can stream DeepSeek models with configurable thinking and reasoning effort, send images to vision models, and browse an advisory model catalog. Connection facts — endpoint, catalog, key, thinking policy — resolve per request, so editing the user settings document changes the next request without a restart. It is one of two structurally different adapters for DeepSeek: the pi-ai twin serves its own route names through a library and additional providers, and both can be mounted side by side.

Table of Contents

• Use this package
• Understand the implementation
• Further Exploration
• Model Experience
• Known Limitations and Deferred Work
• Dev Note

---

Use this package

Mount this plugin when a composition streams DeepSeek models through the harness LLM service. It registers the single deepseek-official route and resolves connection facts per request, so a composition entry plus an optional user settings section drive the whole adapter.

When to choose it

Choose this adapter when the deployment targets DeepSeek's official API, optionally behind an OpenAI-compatible gateway named by baseURL. Choose dsh-llm-pi-ai when the same composition also routes other providers or hand-declared gateways through pi-ai's catalogs; the two adapters can be mounted together because their route names do not collide. Registering any other adapter for deepseek-official fails with DUPLICATE_ADAPTER.

Minimal configuration

- name: '@deepseek-ai/dsh-llm-deepseek'
  config:
    apiKeyEnv: DEEPSEEK_API_KEY  # credential reference, resolved per request
    baseURL: https://api.deepseek.com # optional; $DEEPSEEK_BASE_URL then this default
    reasoningEffort: high        # optional; off | low | high | max
    maxTokens: 256000            # optional per-request output cap
    maxRequestFilesBytes: 134217728
    maxInlineRequestImageBytes: 20971520
    maxImagesPerRequest: 600
    filesApiTimeoutMs: 60000

A request selects the route with provider: deepseek-official; the model id passes through to the wire, so new DeepSeek models need no re-registration. Omitted models advertises deepseek-v4-flash as the fast, economical choice for focused work, deepseek-v4-pro as the stronger, higher-cost choice for complex or quality-critical work, and the image-capable deepseek-v4-flash-vision-exp; each has a 1,000,000-token context window. An explicit list replaces those defaults, and unlisted model ids still pass through as text-only routes. Clients, including model discovery tools, can read the advisory entries through ctx.llm.listModels('deepseek-official'). Image-capable entries may set imagePixelBudget to a positive integer or low, and may set imageMaxBytes.

Field	Default	Meaning
apiKeyEnv	DEEPSEEK_API_KEY	Credential reference resolved per request through the credentials seam, then the environment
baseURL	https://api.deepseek.com	Endpoint base; $DEEPSEEK_BASE_URL wins when set
thinking	enabled	Deployment policy; disabled locks every request to off
reasoningEffort	high	Default effort: off, low, high, or max
maxTokens	256,000	Per-request output cap; a model's own cap and explicit request values win
defaultContextWindow	1,000,000	Capacity fallback for models without an exact value
models	V4 Flash + V4 Pro + V4 Flash Vision Exp	Advisory catalog shown by discovery consumers
streamIdleTimeoutMs	300,000	Maximum provider idle time per outstanding stream read
maxRequestFilesBytes	128 MiB	High watermark for retained request-image bytes before oldest-first offload
maxInlineRequestImageBytes	20 MiB	Independent base64 fallback high watermark
maxImagesPerRequest	600	High watermark for retained request-image count
imageOffloadByteQuantum	64 MiB	Files-mode oldest-prefix removal quantum
inlineImageOffloadByteQuantum	10 MiB	Inline-mode oldest-prefix removal quantum
imageOffloadCountQuantum	20	Count-overflow removal quantum
filesApiTimeoutMs	60,000	Per-image Files resolution deadline
fileExpiresAfterSeconds	604,800	Requested uploaded-image lifetime
fileRefreshMarginSeconds	3,600	Remaining lifetime below which an id is replaced
fileQuotaCleanupBatch	100	Oldest harness-owned files removed before one quota retry
retryPolicy	normal, 5 retries	Provider-owned retry policy executed by dsh-llm-retry

The generated configuration catalog is the exhaustive source for every accepted field and its JSDoc.

Streaming with thinking and images

An image-capable route resolves each durable reference into a deterministic request version under its pixel and byte budgets. imagePixelBudget accepts a positive integer or low; omission uses 640,000 total pixels, low uses 512×512 total pixels, and imageMaxBytes defaults to 1 MiB. Alpha images use WebP effort 0 and opaque images use JPEG on the 85/75/60 quality ladder, keeping the smallest output when every candidate exceeds the target. Every retained image is preceded by text naming its complete attachment id and actual request dimensions. When the current filesystem maps the attachment provider's host object, that text also carries a read-only execution-world path and the extension for a writable copy. Text-only and unlisted routes receive stable attachment placeholders while durable history keeps the image references.

The adapter normally uploads those exact request bytes through the DeepSeek Files API and sends file-id blocks. A failed or timed-out file resolution rebuilds the whole chat request with the same request versions as base64 data URLs; one request never mixes file ids and inline images. Cached ids are scoped by endpoint and API key, refreshed before expiry, invalidated from provider stale-file errors, and resolved through singleflight with waiter-local cancellation. Quota failure deletes one configured batch of the oldest harness-owned files before one upload retry.

Files mode bounds retained request versions by maxRequestFilesBytes and maxImagesPerRequest; inline fallback has its own base64 budget. Both remove an oldest prefix in configured byte or count quanta. Each omitted image gets its own model-visible placeholder with its display name or attachment id and, when available, normalized dimensions, media type, and current read-only path. The stepped high-watermark policy avoids rewriting an old request prefix after every new image.

reasoningEffort selects the advertised default. Exact-model metadata exposes ordered off, low, high, and max efforts with selection guidance when deployment policy permits thinking. low, high, and max enable thinking and serialize as reasoning_effort, while adapter-owned off sends thinking.type: disabled instead. An unsupported value fails with UNSUPPORTED_REASONING_EFFORT before network I/O, and thinking: disabled rejects any non-off effort at plugin load. Requests with purpose: 'session-title' force thinking off to reserve output for visible title text.

Dynamic configuration

Connection facts are re-read once per operation through the optional settings and credentials seams. A llm-deepseek: section in the user settings document overrides any field without a restart; a snapshot that fails a beyond-schema bound keeps the last good facts and logs the failure. The API key resolves per stream call from the same snapshot that supplies the endpoint, image and Files policies, and idle budget, so a rejected settings generation contributes none of them. Image requests resolve the attachment service at request time, so load order does not freeze image availability.

Provider-specific request fields

When ctx.deepseekLlmApiExtensions is present, the adapter prepares its registered top-level fields from the exact serialized base request before fetch. Preparation or field collisions fail before HTTP; after a 2xx response, the adapter accepts every captured contribution before consuming SSE. Transport and non-2xx failures do not accept them. Shipped compositions use this for the optional incremental dsh_session_log field and the default-on active dsh_plugin_packages inventory; both stay outside model input.

Failures and recovery

Non-2xx responses fail with stable codes: AUTH (401/403), QUOTA, RATE_LIMIT, CONTEXT_WINDOW_EXCEEDED, INVALID_REQUEST, SERVER, and HTTP_<status> otherwise; pre-response transport failures throw TRANSPORT, caller aborts throw ABORTED, and stream-idle expiry throws TIMEOUT. Request-extension preparation, field collision, or post-2xx acceptance fails with REQUEST_EXTENSION. A normalized-image rejection names every plausible attachment and its durable position when the provider does not identify a file id. Stale-file rejection invalidates the named mappings (or every mapping used by the attempt) and permits one replacement chat attempt. Protocol violations throw STREAM_CLOSED or MALFORMED_RESPONSE, and a terminal stop with no content blocks becomes EMPTY_RESPONSE, which the default retry policy retries. A request with no key anywhere fails with MISSING_CREDENTIAL, and a malformed credential fails with INVALID_CREDENTIAL naming the reference to fix — never any part of the key.

---

Understand the implementation

Implementation internals — click to expand

This section explains the design behind the adapter; the observable behavior is fully covered in Use this package.

Design philosophy

The plugin is built on one explicit resolve step and one registration fact. resolveAdapterOptions() is the single path from raw config to validated connection facts, and the adapter re-reads those facts through a thunk once per operation — base URL, catalog, request defaults, image and Files policies, and idle budget all take effect on the next request, while an in-flight stream keeps the facts it started with. The only fact captured at registration is the retry policy: when its resolved value changes, the plugin re-registers the route in place, in one synchronous section, so no request observes a gap.

Source map

File	Role
src/index.ts	Plugin entry: Config schema, per-request resolution, settings and credential wiring
src/adapter.ts	The DeepSeekAdapter: model resolution, image projection, Files fallback, streaming with idle timeout
src/file-store.ts + src/files-api.ts	Scoped upload caching, expiry, stale-id recovery, quota cleanup, and remote file operations
src/serialize.ts	Wire serialization: thinking defaults, Files or inline image blocks, history rules
src/sse.ts	eventsource-parser SSE framing for the direct fetch stream
src/translate.ts	SSE payload translation into harness StreamChunk values
src/types.ts	Wire-level types shared by the modules above

Wire flow

One stream() call normally makes one chat request: resolve deterministic request images, prefer Files ids, prepare any registered top-level request extensions, fetch from the resolved baseURL, accept extension transactions after HTTP 2xx, and translate the SSE stream into the harness protocol. File-resolution failure makes the first chat inline; a provider stale-file response permits one replacement attempt, also inline if replacement resolution fails. Every chat and Files call carries shared attribution plus the stable anonymous user id outside model input, and a session call also carries its session id. Reasoning history is serialized back when required, and cache accounting maps DeepSeek's cache-hit metrics into harness usage.

---

Further Exploration

Read these pages when the package-level contract is not enough. They move from the service contract to the twin adapter, the retry executor, and the shared types.

• dsh-llm service — the provider-neutral service this adapter registers on.
• llm-pi-ai adapter — the library-backed twin serving other providers and gateways.
• LLM streaming subsystem — the StreamChunk protocol and adapter contract.
• llm-retry — the retry executor that applies this adapter's retryPolicy.
• DeepSeek request extensions — lifecycle and acceptance semantics for provider-specific top-level fields.
• Session-log upload — the opt-in incremental dsh_session_log contribution.
• Plugin package inventory — the default-on dsh_plugin_packages contribution.
• Twin LLM adapters — why DeepSeek ships two structurally different adapters.
• Mandatory app attribution headers — the identity every provider request carries.

---

Model Experience

DeepSeek request

What the model sees

The selected DeepSeek model receives the harness system prompt, message history, tool schemas, stop sequences, and call config (maxTokens, reasoningEffort, temperature) without adapter-authored prompt prose. Provider-specific request-extension fields remain outside model input. The vision model normally receives retained user and tool-result images as Files API references beside attachment handles and request-preview dimensions. It also receives a normalized-object path when the current execution filesystem maps the attachment provider's host object; the descriptor marks this copy read-only and warns that normalization may have resized or re-encoded the upload. A Files resolution failure sends all retained images as inline data URLs instead, and an over-budget older image keeps the access resolved for that request in its placeholder. Reasoning content from a prior assistant turn is passed back verbatim, whether or not that turn called a tool.

Token effect

Provider tokenization governs exact text and image-token input. The adapter declares per-route imageRequestPricing: it reproduces oldest-first image offload from durable byte lengths and prices each retained image at its projected dimensions with the published v4 vision accounting (14px patch grid, 3:1 downsampling, 384-token cap, worst-case alignment pad). This lets the token meter price image pressure before a request; reported usage remains authoritative. Reasoning passback carries every reasoned turn's chain of thought into later requests, while dropping over-budget images avoids paying those tokens again. Cache-read usage is reported when available. totalTokens is the exact prompt_tokens + completion_tokens aggregate and is omitted if a supplied total_tokens disagrees.

KV Cache effect

An unchanged assembled prefix is eligible for DeepSeek cache reuse, which this adapter reports in usage. Deterministic request-image bytes do not make the full prefix immutable: a changed execution-world path rewrites historical descriptor text, a refreshed upload can replace a file_id, and Files-to-base64 fallback changes the image representation. Any of these, or a model-route, prompt, schema, history, or image-budget change, may prevent reuse from the first affected token; reasoning passback appends on every reasoned turn.

DeepSeek response

What the model sees

Reasoning, text, and raw-string tool arguments are translated into harness chunks for the loop to log and assemble.

Token effect

Generated tokens follow the request's logged reasoning effort and maxTokens; only loop-retained blocks affect later input.

KV Cache effect

Loop-retained response blocks append to the next request and preserve its earlier reusable prefix; dropped blocks have no later cache effect. Changing the provider or model selects a different cache domain.

Known Limitations and Deferred Work

These limits define where the adapter stops and future work begins. They are current package constraints, not a general DeepSeek comparison or a task backlog.

• A settings models list replaces the composition list wholesale — settings-layer merging is per-field, and arrays are one field; per-entry catalog merging would need a keyed shape.
• tool_choice is not mapped — not part of the core vocabulary (shared with the pi-ai twin).
• Requests use raw fetch, not @cordisjs/plugin-http — no shared proxy or interception configuration.
• Plugin-added content block types are skipped — core text and supported image blocks are serialized, and empty tool output crosses the wire as the literal (no output).
• Images are input-only durable attachments — direct external URLs and assistant image output are not supported; DeepSeek input normally uses the Files API and uses inline base64 only for per-request recovery.

Dev Note

Working context for maintainers — click to expand

This Dev Note is non-authoritative working context: undecided directions and notes for maintainers. Shipped behavior and accepted rationale live in the sections above, the package code, and the linked Agent Notes.

• OpenRouter-specific app attribution headers are deferred to a future explicit OpenRouter adapter or mode; OpenAI-compatible gateway requests carry only the shared attribution baseline.
• The off reasoning effort never crosses the wire as reasoning_effort: 'off'; it serializes as thinking: { type: 'disabled' } and omits the field, which keeps the wire spelling valid for gateways that reject unknown effort values.