fix: keep the original baseline for temporary reasoning effort

.changeset/quiet-resets.md

@@ -0,0 +1,5 @@
+---
+"opencode-adaptive-thinking": patch
+---
+
+Reset a temporary reasoning effort to the level in effect before the first override, so repeated changes no longer reset to an intermediate level or skip the reset. Read session history once per tool call with a bounded query, cache provider variants, merge guidance into an existing first system prompt, and remove the runtime Zod dependency.

README.md

@@ -89,6 +89,8 @@ Example persisted change:
 
 The system prompt lists the valid levels for the current session. Cached session state is only used when it is still valid for the current model, so switching models will not advertise or reuse an invalid effort level.
 
+Adaptive-thinking guidance is merged into the first existing system prompt instead of a separate system message, so strict chat templates that allow only one system message keep working.
+
 ## Troubleshooting
 
 If the tool returns `no valid reasoning effort levels are available for this session`, check that the active model exposes variants in OpenCode. Some providers or models may not support reasoning-effort levels.

package.json

@@ -37,9 +37,6 @@
     "verify": "pnpm run format:check && pnpm run lint && pnpm run typecheck && pnpm run test && pnpm run build",
     "version-packages": "changeset version"
   },
-  "dependencies": {
-    "zod": "^4.4.3"
-  },
   "devDependencies": {
     "@changesets/changelog-github": "^0.7.0",
     "@changesets/cli": "^2.31.0",

src/config.ts

@@ -1,26 +1,47 @@
-import * as z from "zod/v4";
-
 export const defaultSystemPrompt =
   "You MUST manage reasoning effort actively. " +
   "Lower it before trivial or routine turns; raise it for ambiguity, debugging, risky changes, or multi-step synthesis. " +
   "Reassess at turn start, after meaningful new evidence, and when the task shifts. " +
   "NEVER leave the current level unchanged by inertia, and NEVER reply to a trivial turn before considering a downshift.";
 
-export const configDefaults = {
+export type Config = {
+  enabled: boolean;
+  quiet: boolean;
+  toolName: string;
+  toolDescription: string;
+  systemPrompt: string;
+};
+
+const defaults: Config = {
   enabled: true,
   quiet: false,
   toolName: "set_reasoning_effort",
   toolDescription: "Set your reasoning effort",
   systemPrompt: defaultSystemPrompt,
 };
 
-export const ConfigSchema = z
-  .object({
-    enabled: z.boolean().default(configDefaults.enabled),
-    quiet: z.boolean().default(configDefaults.quiet),
-    toolName: z.string().default(configDefaults.toolName),
-    toolDescription: z.string().default(configDefaults.toolDescription),
-    systemPrompt: z.string().default(configDefaults.systemPrompt),
-  })
-  .optional()
-  .default(configDefaults);
+export const parseConfig = (options: unknown): { config: Config } | { error: string } => {
+  if (options === undefined) return { config: { ...defaults } };
+  if (typeof options !== "object" || options === null || Array.isArray(options)) {
+    return { error: "options must be an object" };
+  }
+
+  const input = options as Record<string, unknown>;
+  const config = { ...defaults };
+
+  for (const key of ["enabled", "quiet"] as const) {
+    const value = input[key];
+    if (value === undefined) continue;
+    if (typeof value !== "boolean") return { error: `${key} must be a boolean` };
+    config[key] = value;
+  }
+
+  for (const key of ["toolName", "toolDescription", "systemPrompt"] as const) {
+    const value = input[key];
+    if (value === undefined) continue;
+    if (typeof value !== "string") return { error: `${key} must be a string` };
+    config[key] = value;
+  }
+
+  return { config };
+};