feat: support --effort flag via provider option and model suffix

src/claude-code-language-model.ts

@@ -185,6 +185,7 @@ export class ClaudeCodeLanguageModel implements LanguageModelV2 {
       skipPermissions: this.config.skipPermissions !== false,
       includeSessionId: false,
       model: this.modelId,
+      effort: this.config.effort,
     })
 
     log.info("doGenerate starting", {
@@ -505,6 +506,7 @@ export class ClaudeCodeLanguageModel implements LanguageModelV2 {
       sessionKey: sk,
       skipPermissions,
       model: this.modelId,
+      effort: this.config.effort,
     })
 
     const stream = new ReadableStream<LanguageModelV2StreamPart>({

src/index.ts

@@ -21,6 +21,7 @@ export function createClaudeCode(
       cliPath,
       cwd,
       skipPermissions: settings.skipPermissions ?? true,
+      effort: settings.effort,
     })
   }
 

src/session-manager.ts

@@ -102,13 +102,16 @@ export function spawnClaudeProcess(
   return ap
 }
 
+const VALID_EFFORTS = new Set(["low", "medium", "high", "xhigh", "max"])
+
 export function buildCliArgs(opts: {
   sessionKey: string
   skipPermissions: boolean
   includeSessionId?: boolean
   model?: string
+  effort?: string
 }): string[] {
-  const { sessionKey, skipPermissions, includeSessionId = true, model } = opts
+  const { sessionKey, skipPermissions, includeSessionId = true, model, effort } = opts
   const args = [
     "--output-format",
     "stream-json",
@@ -117,8 +120,23 @@ export function buildCliArgs(opts: {
     "--verbose",
   ]
 
-  if (model) {
-    args.push("--model", model)
+  // Allow per-model effort override via "modelId:effort" (e.g. "opus:high").
+  let resolvedModel = model
+  let resolvedEffort = effort
+  if (model && model.includes(":")) {
+    const [baseModel, suffix] = model.split(":", 2)
+    if (suffix && VALID_EFFORTS.has(suffix)) {
+      resolvedModel = baseModel
+      resolvedEffort = suffix
+    }
+  }
+
+  if (resolvedModel) {
+    args.push("--model", resolvedModel)
+  }
+
+  if (resolvedEffort && VALID_EFFORTS.has(resolvedEffort)) {
+    args.push("--effort", resolvedEffort)
   }
 
   if (includeSessionId) {

src/types.ts

@@ -1,15 +1,19 @@
+export type ClaudeEffort = "low" | "medium" | "high" | "xhigh" | "max"
+
 export interface ClaudeCodeConfig {
   provider: string
   cliPath: string
   cwd?: string
   skipPermissions?: boolean
+  effort?: ClaudeEffort
 }
 
 export interface ClaudeCodeProviderSettings {
   cliPath?: string
   cwd?: string
   name?: string
   skipPermissions?: boolean
+  effort?: ClaudeEffort
 }
 
 /**