refactor(llm): drop the inert request knobs — prefill and strict

GenerateOptions.prefill had no production setter and both adapters
rejected it with LlmError('UNSUPPORTED') — its entire observable
behavior was two throws, each pinned by one adapter test. DeepSeek's
chat-prefix completion is a Beta feature on a base URL neither adapter
targets. ToolSchema.strict was threaded through defineTool, the
registry's schemas() allowlist, the deepseek wire mapping, a per-tool
payload-patching pass in the pi-ai adapter, and a tool-catalog render
row, yet no shipped tool set it and the internal endpoint story for
strict mode was never built.

Remove both fields end-to-end: the vocabulary in dsh-llm, the adapter
guards and wire branches, the dsh-tools threading, the tool-catalog
Strict row, the pinning tests, the core.md pastes, the adapter README
rows, and the cookbook line that used prefill as the UNSUPPORTED
example (now stated generically). The pi-ai payload fixup keeps the
half with a job: pi-ai stamps strict:false on every serialized tool,
so the fixup scrubs it unconditionally for wire parity with the
hand-rolled twin (per-tool set/delete machinery gone). temperature/
stop/maxTokens are untouched — honored end-to-end by both adapters.

Each knob returns with its first real producer: prefill with an
adapter that implements chat-prefix completion, strict with a tool
that wants it and a beta-endpoint story.

RFC: docs/rfc/implemented/simplification/2026-07-04-drop-inert-request-knobs.md
(moved from proposed/, amended to shipped reality); the content-block
vocabulary RFC's consequence line now records prefill as producer-gated.

packages/llm/llm-deepseek/README.md

@@ -28,12 +28,10 @@ A second, independent implementation of the same seam exists in `@deepseek-ai/ds
 - Streaming only (`stream_options.include_usage` always on). `usage` may arrive attached to the finish chunk or as a trailing usage-only chunk — the translator defers both to `[DONE]`, so `usage` always precedes `finish` and nothing follows `finish`.
 - The first thinking-mode chunk carries `reasoning_content: ""` — handled (no spurious reasoning block).
 - **Reasoning passback rule**: on assistant turns that carried tool calls, `reasoning_content` is serialized back in history (required by the API in thinking mode); on tool-call-free turns it is dropped (ignored anyway — saves tokens).
-- `strict` on tool schemas passes through (officially Beta; the public API wants the `/beta` base URL for it, the internal endpoint accepts it directly).
 - Cache accounting: `cacheReadTokens` ← `prompt_cache_hit_tokens` / `prompt_tokens_details.cached_tokens`; DeepSeek reports no cache-write metric.
 
 ## Limitations (MVP, documented deliberately)
 
-- `prefill` throws `LlmError('UNSUPPORTED')` — DeepSeek's chat-prefix completion is a Beta feature on the `/beta` base URL; future work.
 - `tool_choice` is not mapped (not part of the core vocabulary).
 
 ## Errors

packages/llm/llm-deepseek/src/serialize.ts

@@ -15,7 +15,6 @@
  * @module dsh-llm-deepseek/serialize
  */
 
-import { LlmError } from '@deepseek-ai/dsh-llm'
 import type { ContentBlock, GenerateOptions, Message } from '@deepseek-ai/dsh-llm'
 import type { WireMessage, WireRequest, WireTool } from './types.ts'
 
@@ -98,19 +97,8 @@ export function serializeMessages(messages: Message[]): WireMessage[] {
   return wire
 }
 
-/**
- * Build the full wire request. Throws `LlmError('UNSUPPORTED')` for
- * `prefill` (DeepSeek's chat-prefix completion is a Beta feature on a
- * different base URL — see README).
- */
+/** Build the full wire request. */
 export function serializeRequest(options: GenerateOptions, defaults: RequestDefaults = {}): WireRequest {
-  if (options.prefill !== undefined) {
-    throw new LlmError(
-      'prefill is not supported by the DeepSeek adapter (Beta chat-prefix completion is future work)',
-      'UNSUPPORTED',
-    )
-  }
-
   const messages: WireMessage[] = []
   if (options.system !== undefined) {
     messages.push({ role: 'system', content: options.system })
@@ -123,8 +111,6 @@ export function serializeRequest(options: GenerateOptions, defaults: RequestDefa
       name: tool.name,
       description: tool.description,
       parameters: tool.parameters,
-      // strict is officially supported (Beta); pass the tool author's choice.
-      ...tool.strict !== undefined ? { strict: tool.strict } : {},
     },
   }))
 

packages/llm/llm-deepseek/src/types.ts

@@ -78,8 +78,6 @@ export interface WireTool {
     name: string
     description: string
     parameters: Record<string, unknown>
-    /** Beta: strict schema adherence (official: requires the /beta base URL). */
-    strict?: boolean
   }
 }
 

packages/llm/llm-deepseek/tests/serialize.spec.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest'
-import { CallId, LlmError } from '@deepseek-ai/dsh-llm'
+import { CallId } from '@deepseek-ai/dsh-llm'
 import type { ContentBlock, GenerateOptions, Message } from '@deepseek-ai/dsh-llm'
 import { serializeMessages, serializeRequest } from '@deepseek-ai/dsh-llm-deepseek'
 
@@ -155,17 +155,17 @@ describe('serializeRequest', () => {
     expect(wire.stop).toEqual(['END'])
   })
 
-  it('maps tools with strict passthrough', () => {
+  it('maps tools to the wire function shape', () => {
     const wire = serializeRequest(request({
       messages: history,
       tools: [
         { name: 'a', description: 'A', parameters: { type: 'object', properties: {} } },
-        { name: 'b', description: 'B', parameters: { type: 'object', properties: {} }, strict: true },
+        { name: 'b', description: 'B', parameters: { type: 'object', properties: { x: { type: 'string' } } } },
       ],
     }))
     expect(wire.tools).toEqual([
       { type: 'function', function: { name: 'a', description: 'A', parameters: { type: 'object', properties: {} } } },
-      { type: 'function', function: { name: 'b', description: 'B', parameters: { type: 'object', properties: {} }, strict: true } },
+      { type: 'function', function: { name: 'b', description: 'B', parameters: { type: 'object', properties: { x: { type: 'string' } } } } },
     ])
   })
 
@@ -185,17 +185,6 @@ describe('serializeRequest', () => {
     expect(wire.thinking).toBeUndefined()
     expect(wire.reasoning_effort).toBeUndefined()
   })
-
-  it('rejects prefill with an UNSUPPORTED LlmError', () => {
-    expect(() => serializeRequest(request({ prefill: [{ type: 'text', text: 'Sure' }] })))
-      .toThrow(LlmError)
-    try {
-      serializeRequest(request({ prefill: [] }))
-      expect.unreachable()
-    } catch (error) {
-      expect((error as LlmError).code).toBe('UNSUPPORTED')
-    }
-  })
 })
 
 describe('review fixes: assistant content shapes', () => {