feat: Read My Mind phase 2, the predictor and the brain button

The feature as pitched in docs/readmymind-plan.md: pressing the header brain button predicts the prompt you were about to type, from the case's intent profile plus everything the session already knows. Backend: - readmymind-context.ts: pure budgeted context assembler (9 ranked sources: pending approval dialog, user goals, last assistant turn tail, recent prompts, tool activity, git workspace signals, away context, sibling sessions, rethink state; 30 KB budget, whole-section drop from the bottom of the ranking, trust tiers stated in the prompt) - readmymind-collectors.ts: transcript tail reader (the live watcher keeps only a 500-char snippet) and git signal collection (execFile, 2s timeout, skipped for remote-SSH cases) - readmymind-predictor.ts: one-shot claude -p in a throwaway tmux session, opus by default (readMyMindModel setting), strict JSON contract with 1-3 suggestions (continue / verify / redirect), newline stripping, 90s timeout; mutable singleton so route tests can stub it - POST /api/sessions/:id/readmymind: claude-mode only (400), one prediction in flight per session (409 CONFLICT), rethink body { steer, rejected }; ownership via findSessionOrFail Frontend: - readmymind-ui.js (loadorder 11.3): header brain button, marker-hidden until readMyMindEnabled is ON, desktop only (phone key is phase 3); modal with editable suggestion + rationale and Send / Insert / Rethink / Dismiss; suggestion text rendered via value/textContent only and nothing ever auto-sends - App Settings -> Panels checkbox for readMyMindEnabled; en + zh-CN strings Verified end to end against a live isolated instance: transcript capture, a real opus prediction grounded in the stated goals, rethink steering, the 409, and the browser modal incl. Insert leaving the text unsubmitted on the composer. 41 new unit/route tests; full test:ci sweep green (4680 tests). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-10-08 00:19:42 +02:00 · 2026-08-09 23:05:11 +02:00
parent 8a6570e22d
commit 94abcf29dc
26 changed files with 1783 additions and 24 deletions
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+/**
+ * @fileoverview Read My Mind collectors: the IO feeding the pure context
+ * assembler (`readmymind-context.ts`).
+ *
+ * - `readTranscriptSignals()`: tail-reads the session's Claude transcript
+ *   JSONL for the full last assistant text plus recent tool calls. The live
+ *   `TranscriptWatcher` keeps only a 500-char snippet, no tool history, and
+ *   starts empty after a server restart, so prediction reads the file itself:
+ *   on-demand, bounded, cold-start-proof. The line parse is pure
+ *   (`parseTranscriptSignals`) for fixture tests.
+ *
+ * - `collectWorkspaceSignals()`: git branch/status/log via `execFile` in the
+ *   session's workingDir with a 2s timeout, plus `.changeset/*.md` presence.
+ *   Callers skip it for remote-SSH cases (workingDir is not local; Docker
+ *   cases are fine, the workspace is bind-mounted at the same host path).
+ *   Non-git dirs resolve to null and the section is simply omitted.
+ */
+
+import { execFile } from 'node:child_process';
+import { open, readdir, stat } from 'node:fs/promises';
+import { join } from 'node:path';
+import { promisify } from 'node:util';
+import type { PredictionToolCall, WorkspaceSignals } from './readmymind-context.js';
+
+const execFileAsync = promisify(execFile);
+
+// ========== Transcript signals ==========
+
+/** How much of the transcript tail to read. Turns are append-only JSONL, so the tail holds the newest entries. */
+export const TRANSCRIPT_TAIL_BYTES = 256 * 1024;
+
+/** Safety cap on the extracted assistant text (the assembler truncates further). */
+const MAX_ASSISTANT_CHARS = 12_000;
+
+/** Max recent tool calls retained. */
+export const MAX_TRANSCRIPT_TOOLS = 10;
+
+const TOOL_DETAIL_KEYS = ['file_path', 'command', 'pattern', 'path', 'url', 'query', 'description'] as const;
+const MAX_TOOL_DETAIL_CHARS = 80;
+
+export interface TranscriptSignals {
+  lastAssistantText: string | null;
+  recentTools: PredictionToolCall[];
+}
+
+interface TranscriptBlock {
+  type?: string;
+  text?: string;
+  name?: string;
+  id?: string;
+  input?: Record<string, unknown>;
+  tool_use_id?: string;
+  is_error?: boolean;
+}
+
+/** One-line argument summary for a tool call, e.g. `Edit src/foo.ts` or `Bash npm test`. */
+function summarizeToolInput(input: Record<string, unknown> | undefined): string | undefined {
+  if (!input) return undefined;
+  for (const key of TOOL_DETAIL_KEYS) {
+    const value = input[key];
+    if (typeof value === 'string' && value.trim()) {
+      return value.replace(/\s+/g, ' ').trim().slice(0, MAX_TOOL_DETAIL_CHARS);
+    }
+  }
+  return undefined;
+}
+
+/**
+ * Parse transcript JSONL lines into prediction signals. Pure; malformed lines
+ * are skipped (the tail read starts mid-file, so the first line usually is).
+ */
+export function parseTranscriptSignals(lines: string[], maxTools: number = MAX_TRANSCRIPT_TOOLS): TranscriptSignals {
+  let lastAssistantText: string | null = null;
+  const tools: (PredictionToolCall & { id?: string })[] = [];
+
+  for (const line of lines) {
+    if (!line.trim()) continue;
+    let entry: { type?: string; message?: { content?: unknown } };
+    try {
+      entry = JSON.parse(line) as { type?: string; message?: { content?: unknown } };
+    } catch {
+      continue;
+    }
+
+    const content = entry.message?.content;
+    if (entry.type === 'assistant') {
+      if (typeof content === 'string') {
+        if (content.trim()) lastAssistantText = content.slice(0, MAX_ASSISTANT_CHARS);
+      } else if (Array.isArray(content)) {
+        const texts: string[] = [];
+        for (const block of content as TranscriptBlock[]) {
+          if (block.type === 'text' && block.text) {
+            texts.push(block.text);
+          } else if (block.type === 'tool_use' && block.name) {
+            tools.push({ name: block.name, detail: summarizeToolInput(block.input), id: block.id });
+          }
+        }
+        if (texts.length > 0) lastAssistantText = texts.join('\n').slice(0, MAX_ASSISTANT_CHARS);
+      }
+    } else if (entry.type === 'user' && Array.isArray(content)) {
+      for (const block of content as TranscriptBlock[]) {
+        if (block.type === 'tool_result' && block.is_error && block.tool_use_id) {
+          const tool = tools.find((t) => t.id === block.tool_use_id);
+          if (tool) tool.failed = true;
+        }
+      }
+    }
+  }
+
+  return {
+    lastAssistantText,
+    recentTools: tools.slice(-maxTools).map(({ name, detail, failed }) => ({ name, detail, failed })),
+  };
+}
+
+/**
+ * Read the transcript tail and extract prediction signals. Returns null when
+ * the file is missing or unreadable (the sections are simply omitted).
+ */
+export async function readTranscriptSignals(transcriptPath: string): Promise<TranscriptSignals | null> {
+  let handle;
+  try {
+    const info = await stat(transcriptPath);
+    const offset = Math.max(0, info.size - TRANSCRIPT_TAIL_BYTES);
+    const length = info.size - offset;
+    if (length <= 0) return { lastAssistantText: null, recentTools: [] };
+
+    handle = await open(transcriptPath, 'r');
+    const buffer = Buffer.alloc(length);
+    await handle.read(buffer, 0, length, offset);
+    const lines = buffer.toString('utf-8').split('\n');
+    // A mid-file start point means the first line is a partial record.
+    if (offset > 0) lines.shift();
+    return parseTranscriptSignals(lines);
+  } catch {
+    return null;
+  } finally {
+    await handle?.close().catch(() => {});
+  }
+}
+
+// ========== Workspace signals ==========
+
+const GIT_TIMEOUT_MS = 2_000;
+const MAX_STATUS_LINES = 30;
+
+/**
+ * Collect git signals from a local workingDir. Null when the dir is not a git
+ * repo (or git is unavailable); individual sub-signals fail soft.
+ */
+export async function collectWorkspaceSignals(workingDir: string): Promise<WorkspaceSignals | null> {
+  const git = async (args: string[]): Promise<string> => {
+    const { stdout } = await execFileAsync('git', args, {
+      cwd: workingDir,
+      timeout: GIT_TIMEOUT_MS,
+      maxBuffer: 256 * 1024,
+    });
+    return stdout;
+  };
+
+  let branch: string;
+  try {
+    branch = (await git(['branch', '--show-current'])).trim();
+  } catch {
+    return null; // Not a git repo (or no git): the section is omitted.
+  }
+
+  const signals: WorkspaceSignals = { branch: branch || undefined };
+
+  try {
+    const status = (await git(['status', '--short'])).trimEnd();
+    signals.statusShort = status ? status.split('\n').slice(0, MAX_STATUS_LINES).join('\n') : '';
+  } catch {
+    // Fail soft: branch alone is still useful.
+  }
+
+  try {
+    signals.recentCommits = (await git(['log', '--oneline', '-5'])).trimEnd();
+  } catch {
+    // A repo with no commits yet: omit.
+  }
+
+  try {
+    const entries = await readdir(join(workingDir, '.changeset'));
+    signals.hasChangesets = entries.some((name) => name.endsWith('.md') && name.toLowerCase() !== 'readme.md');
+  } catch {
+    // No .changeset dir: not a changesets repo.
+  }
+
+  return signals;
+}