Maintenance: pricing date, token est. label, listPaths refresh, MUTATING derive

src/cli.tsx

@@ -398,6 +398,7 @@ const hooks: AppHooks = {
     for await (const rel of walk({ limit: 5000 })) found.push(rel);
     return found;
   },
+  fileChangeSeq: () => session.fileChangeSeq,
   customCommands: () => customCommands,
   registry: {
     list: async () => {

src/permission.ts

@@ -190,28 +190,43 @@ export function resolve(rules: PermissionEntry | undefined, tool: string, input:
  * Read-only tools run; anything that writes or executes asks. `.env` is denied on
  * read because a model that greps for a config value will find a credential, and
  * "it was in the context" is not recoverable.
+ *
+ * Mutating entries are derived from `_meta.mutating` (tools.ts MUTATING_TOOLS) so
+ * a new write cannot be added without being gated — the loop below is the single
+ * source. Only the non-mutating special cases are hand-written here.
  */
-export const DEFAULT_PERMISSIONS: PermissionConfig = {
+const BASE_PERMISSIONS: PermissionConfig = {
   read_file: { '*': 'allow', '*.env': 'deny', '*.env.*': 'deny', '*.env.example': 'allow', '*.pem': 'deny' },
   read_many_files: { '*': 'allow', '*.env': 'deny', '*.env.*': 'deny', '*.env.example': 'allow', '*.pem': 'deny' },
-  write_file: 'ask',
-  edit_file: 'ask',
-  multi_edit: 'ask',
-  apply_patch: 'ask',
-  move_file: 'ask',
-  delete_file: 'ask',
-  insert_lines: 'ask',
-  delete_lines: 'ask',
-  replace_lines: 'ask',
-  append_file: 'ask',
-  prepend_file: 'ask',
-  bash: 'ask',
   web_fetch: 'ask',
-  mcp_call: 'ask',
   mcp_list: 'allow',
   mcp_inspect: 'allow',
 };
 
+// Filled at import time from MUTATING_TOOLS so `_meta.mutating` is the single source.
+// Dynamic import avoids a static cycle (tools.ts does not import permission.ts).
+let _defaultPermissions: PermissionConfig | undefined;
+function buildDefaults(): PermissionConfig {
+  if (_defaultPermissions) return _defaultPermissions;
+  const out: PermissionConfig = { ...BASE_PERMISSIONS };
+  try {
+    // eslint-disable-next-line @typescript-eslint/no-require-imports
+    const toolsMod = require('./tools') as { MUTATING_TOOLS?: readonly string[] };
+    for (const name of toolsMod.MUTATING_TOOLS ?? []) {
+      if (!(name in out)) out[name] = 'ask';
+    }
+  } catch {
+    // tests that import permission in isolation still get BASE + known mutating fallback
+    for (const name of ['write_file','edit_file','multi_edit','apply_patch','move_file','delete_file','insert_lines','delete_lines','replace_lines','append_file','prepend_file','bash','mcp_call'] as const) {
+      if (!(name in out)) (out as Record<string, PermissionEntry>)[name] = 'ask';
+    }
+  }
+  _defaultPermissions = out;
+  return out;
+}
+
+export const DEFAULT_PERMISSIONS: PermissionConfig = buildDefaults();
+
 /** Session, plugin, and read-only tools that never gate. */
 const FREE = new Set([
   'glob',

src/pricing.ts

@@ -1,3 +1,12 @@
+export const PRICING_VERIFIED_AT = '2026-09-09';
+
+/**
+ * Source: hand-entered from provider pricing pages as of PRICING_VERIFIED_AT.
+ * Anthropic https://www.anthropic.com/pricing, OpenAI https://openai.com/api/pricing,
+ * DeepSeek https://api-docs.deepseek.com/quick_start/pricing, xAI https://x.ai/api.
+ * Rates drift; verify before billing. Update PRICING_VERIFIED_AT when changing RATES.
+ * Displayed in /cost so a stale table is visible.
+ */
 export type Rate = { inputPerMTok: number; outputPerMTok: number };
 
 /**

src/prune.ts

@@ -196,9 +196,11 @@ export function droppedSpan(before: ModelMessage[], after: ModelMessage[]): Mode
 const KEEP_LADDER = [64, 32, 16, 8, 4] as const;
 
 /**
- * Token estimate used by the session harness. `len/4` undercounts tool envelopes
- * (role + toolCallId + providerOptions); `len/3.6 + 8*msgs` tracks cl100k closer
- * without pulling a tokenizer. Exported so session and tests share it.
+ * Token estimate used by the session harness — heuristic, not a tokenizer.
+ * `len/4` undercounts tool envelopes (role + toolCallId + providerOptions);
+ * `len/3.6 + 8*msgs` tracks cl100k closer without pulling a tokenizer.
+ * Every display of its value must label it an estimate (e.g. "~N tokens (est.)").
+ * Exported so session and tests share it.
  */
 export function estimateTokens(messages: ModelMessage[]): number {
   return Math.round(JSON.stringify(messages).length / 3.6 + messages.length * 8);

src/session.ts

@@ -387,6 +387,9 @@ export class Session {
   canUndo(): boolean { return this.snapshots.canUndo(); }
   canRedo(): boolean { return this.snapshots.canRedo(); }
 
+  /** Monotonically increments when a file is first touched in a turn — lets the `@` completer know its cache is stale. */
+  fileChangeSeq = 0;
+
   async undo(): Promise<string> {
     const snap = this.snapshots.popForUndo();
     if (!snap) throw new Error('nothing to undo');
@@ -426,6 +429,7 @@ export class Session {
         } else {
           await Bun.write(abs, st.content ?? '');
         }
+        this.fileChangeSeq += 1;
       } catch {
         // best-effort per file; one failure should not stop the rest
       }
@@ -599,6 +603,7 @@ export class Session {
         try { content = await Bun.file(abs).text(); } catch { content = null; }
       }
       this.turnBeforeFiles.set(abs, { existed: exists, content });
+      this.fileChangeSeq += 1;
     });
     this.messages.push({ role: 'user', content: userText });
     this.opts.onChange?.(this.messages);

src/ui/App.tsx

@@ -63,8 +63,10 @@ export type AppHooks = {
   saveSession: () => Promise<string>;
   /** Loaded AGENTS.md-style files, for /context. */
   instructionFiles: () => string[];
-  /** Ignore-aware workspace paths for `@` completion, loaded on first use. */
+  /** Ignore-aware workspace paths for `@` completion, loaded on first use and invalidated when files change. */
   listPaths: () => Promise<string[]>;
+  /** Monotonically increments when the workspace changes — lets the `@` completer know to re-walk. */
+  fileChangeSeq: () => number;
   /** Custom slash commands from markdown files, for the menu and the parser. */
   customCommands?: () => readonly CustomCommand[];
   /** Registry index, installed set, and the install/remove actions. */
@@ -177,7 +179,8 @@ export function App({
   const highlightedPath = fileMatches[Math.min(fileIndex, Math.max(0, fileMatches.length - 1))];
 
   // The walk costs a full ignore-aware traversal, so it happens on the first `@`
-  // rather than at startup, and only once.
+  // rather than at startup, and re-runs when files change (listPaths is cached
+  // in hook, but App keeps seq so a stale `paths` is dropped).
   useEffect(() => {
     if (token === undefined || paths !== undefined) return;
     let live = true;
@@ -189,6 +192,12 @@ export function App({
     };
   }, [hooks, paths, token]);
 
+  // A file mutated this turn: drop the cached walk so next `@` re-walks.
+  const seq = hooks.fileChangeSeq();
+  useEffect(() => {
+    setPaths(undefined);
+  }, [seq]); // eslint-disable-line react-hooks/exhaustive-deps
+
   useEffect(() => bridge.bind(setPending), [bridge]);
   useEffect(() => askBridge?.bind(setAsking), [askBridge]);
 
@@ -425,7 +434,7 @@ export function App({
               if (ev.inputTokens !== undefined) {
                 merged.push({
                   kind: 'info',
-                  text: `${usageLine(hooks.config().model, ev.inputTokens, ev.outputTokens ?? 0)}  (~${session.estimatedTokens()} in context)`,
+                  text: `${usageLine(hooks.config().model, ev.inputTokens, ev.outputTokens ?? 0)}  (~${session.estimatedTokens()} est. in context)`,
                   key: nextKey(),
                 });
               }

src/ui/panel-bodies.ts

@@ -1,4 +1,4 @@
-import { costOf, formatUsd } from '../pricing';
+import { costOf, formatUsd, PRICING_VERIFIED_AT } from '../pricing';
 import type { Session } from '../session';
 import { toolSetOf } from '../tools';
 import { todoLines } from './transcript';
@@ -58,7 +58,8 @@ export function costPanel(
     );
   }
 
-  lines.push(`- context: ~${session.estimatedTokens()} tokens`, `- agent: \`${info.agent}\` thinking \`${info.thinking}\``);
+  lines.push(`- context: ~${session.estimatedTokens()} tokens (est.)`, `- agent: \`${info.agent}\` thinking \`${info.thinking}\``);
+  lines.push(`- pricing verified: ${PRICING_VERIFIED_AT} (est., verify before billing)`);
   return { title: 'cost', hint: `session ${info.sessionId}`, body: lines.join('\n') };
 }