fix(sync): forward delegated model tuning params

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/tools/call-omo-agent/sync-executor.test.ts

@@ -8,6 +8,11 @@ type PromptAsyncInput = {
     agent: string
     tools: Record<string, boolean>
     parts: Array<{ type: string; text: string }>
+    model?: { providerID: string; modelID: string }
+    variant?: string
+    temperature?: number
+    topP?: number
+    options?: Record<string, unknown>
   }
 }
 
@@ -141,6 +146,56 @@ describe("executeSync", () => {
     )
   })
 
+  test("forwards delegated model tuning params in the sync prompt body", async () => {
+    //#given
+    const executeSync = await importExecuteSync()
+    const deps = createDependencies()
+    const toolContext = createToolContext()
+    const recorder = createPromptAsyncRecorder()
+    const args = {
+      subagent_type: "explore",
+      description: "test task",
+      prompt: "find something",
+      run_in_background: false,
+    }
+    const model = {
+      providerID: "openai",
+      modelID: "gpt-5.4",
+      variant: "high",
+      temperature: 0.12,
+      top_p: 0.34,
+      maxTokens: 5678,
+      reasoningEffort: "medium",
+      thinking: { type: "disabled" as const },
+    }
+
+    //#when
+    await executeSync(
+      args,
+      toolContext,
+      createContext(recorder.promptAsync) as never,
+      deps,
+      undefined,
+      undefined,
+      model,
+    )
+
+    //#then
+    const promptInput = recorder.getCapturedInput()
+    expect(promptInput?.body.model).toEqual({
+      providerID: "openai",
+      modelID: "gpt-5.4",
+    })
+    expect(promptInput?.body.variant).toBe("high")
+    expect(promptInput?.body.temperature).toBe(0.12)
+    expect(promptInput?.body.topP).toBe(0.34)
+    expect(promptInput?.body.options).toEqual({
+      maxTokens: 5678,
+      reasoningEffort: "medium",
+      thinking: { type: "disabled" },
+    })
+  })
+
   test("records metadata with description and created session id", async () => {
     //#given
     const executeSync = await importExecuteSync()

src/tools/call-omo-agent/sync-executor.ts

@@ -3,6 +3,7 @@ import type { PluginInput } from "@opencode-ai/plugin"
 import { subagentSessions, syncSubagentSessions } from "../../features/claude-code-session-state"
 import { clearSessionFallbackChain, setSessionFallbackChain } from "../../hooks/model-fallback/hook"
 import { getAgentToolRestrictions, log } from "../../shared"
+import { applySessionPromptParams } from "../../shared/session-prompt-params-helpers"
 import type { DelegatedModelConfig } from "../../shared/model-resolution-types"
 import type { FallbackEntry } from "../../shared/model-requirements"
 import { waitForCompletion } from "./completion-poller"
@@ -34,6 +35,24 @@ const defaultDeps: ExecuteSyncDeps = {
   clearSessionFallbackChain,
 }
 
+function buildPromptGenerationParams(model: DelegatedModelConfig | undefined): Record<string, unknown> {
+  if (!model) {
+    return {}
+  }
+
+  const promptOptions: Record<string, unknown> = {
+    ...(model.reasoningEffort ? { reasoningEffort: model.reasoningEffort } : {}),
+    ...(model.thinking ? { thinking: model.thinking } : {}),
+    ...(model.maxTokens !== undefined ? { maxTokens: model.maxTokens } : {}),
+  }
+
+  return {
+    ...(model.temperature !== undefined ? { temperature: model.temperature } : {}),
+    ...(model.top_p !== undefined ? { topP: model.top_p } : {}),
+    ...(Object.keys(promptOptions).length > 0 ? { options: promptOptions } : {}),
+  }
+}
+
 export async function executeSync(
   args: CallOmoAgentArgs,
   toolContext: {
@@ -69,6 +88,8 @@ export async function executeSync(
       appliedFallbackChain = true
     }
 
+    applySessionPromptParams(sessionID, model)
+
     await Promise.resolve(
       toolContext.metadata?.({
         title: args.description,
@@ -92,6 +113,7 @@ export async function executeSync(
           parts: [{ type: "text", text: args.prompt }],
           ...(model ? { model: { providerID: model.providerID, modelID: model.modelID } } : {}),
           ...(model?.variant ? { variant: model.variant } : {}),
+          ...buildPromptGenerationParams(model),
         },
       })
     } catch (error) {