feat(plugin): session-recap injection — personalized onset greeting

packages/extension/opencode-plugin/amicode_context.ts

@@ -1,12 +1,12 @@
 // ============================================================================
 // amicode_context — an opencode plugin that injects live stack-state context
-// (solver mode, routing, active problem, live runs) into every system prompt
-// via the `experimental.chat.system.transform` hook.
+// (solver mode, routing, active problem, live runs, recent sessions) into
+// every system prompt via the `experimental.chat.system.transform` hook.
 //
 // RUNTIME: same constraints as amicode_tools.ts — executes inside opencode's
 // embedded Bun runtime, registered by absolute path via OPENCODE_CONFIG_CONTENT
 // `plugin: ["<abs>"]`. Exactly ONE export (the legacy-plugin scan constraint).
-// All imports are sibling modules using node: builtins only.
+// All imports are sibling modules using node:/bun: builtins only.
 //
 // This is a SECOND plugin file alongside amicode_tools.ts; it is registered as
 // a separate entry in the `plugin` array and operates independently from the
@@ -15,14 +15,16 @@
 // ============================================================================
 
 import { buildStackStateBlock } from "./stack_state";
+import { buildRecentSessionsBlock } from "./session_recap";
 
-console.error("[amicode-context] loaded — stack-state injection plugin (experimental.chat.system.transform)");
+console.error("[amicode-context] loaded — stack-state + session-recap injection plugin");
 
 export const AmicodeContext = async () => ({
-  "experimental.chat.system.transform": (
-    _input: { sessionID?: string; model?: string },
+  "experimental.chat.system.transform": async (
+    input: { sessionID?: string; model?: string },
     output: { system: string[] },
-  ): void => {
+  ): Promise<void> => {
+    // Stack state (solver mode, active problem, runs, fleet, vault)
     try {
       const block = buildStackStateBlock();
       if (block) {
@@ -32,5 +34,16 @@ export const AmicodeContext = async () => ({
       console.error(`[amicode-context] buildStackStateBlock failed: ${e instanceof Error ? e.message : String(e)}`);
       // Never throw — a failing hook must not break the prompt build.
     }
+
+    // Recent sessions recap (from the opencode session DB)
+    try {
+      const recapBlock = buildRecentSessionsBlock(input.sessionID);
+      if (recapBlock) {
+        output.system.push(recapBlock);
+      }
+    } catch (e) {
+      console.error(`[amicode-context] buildRecentSessionsBlock failed: ${e instanceof Error ? e.message : String(e)}`);
+      // Never throw — graceful degradation: no recap is better than a crash.
+    }
   },
 });

packages/extension/opencode-plugin/session_recap.ts

@@ -0,0 +1,330 @@
+// ============================================================================
+// session_recap — reads recent sessions from the opencode SQLite DB, caches
+// per-session summaries to disk, and composes a markdown block for prompt
+// injection. Uses bun:sqlite (Bun built-in, no npm dep) for DB reads.
+//
+// RUNTIME: Bun-embedded opencode plugin. Imports: bun:sqlite, node:fs,
+// node:path, node:os. No npm packages.
+//
+// The LLM summarization step is deferred to a future iteration — for now we
+// extract a mechanical recap from message content (user prompts + assistant
+// text parts). This gives us the full pipeline (DB → cache → markdown) without
+// requiring an LLM call inside the plugin, which would need provider config
+// the plugin doesn't have access to. The mechanical extract is good enough for
+// the onset router to personalize the greeting.
+//
+// TEST SEAMS:
+//   AMICODE_SESSION_RECAP_CACHE_DIR — override the cache directory
+//   OPENCODE_DB — override the DB path (shared with opencode itself)
+// ============================================================================
+
+import * as fs from "node:fs";
+import * as path from "node:path";
+import * as os from "node:os";
+
+// ── Types (exported for testing) ─────────────────────────────────────────────
+
+export interface SessionRow {
+  id: string;
+  title: string;
+  parent_id: string | null;
+  time_created: number;
+  time_updated: number;
+}
+
+export interface SessionRecap {
+  session_id: string;
+  title: string;
+  created: string; // ISO
+  recap: string;
+  summarized_at: string; // ISO
+}
+
+// ── Configuration ────────────────────────────────────────────────────────────
+
+export const RECAP_WINDOW_DAYS = 7;
+export const MAX_RECAPS = 10;
+export const MIN_ASSISTANT_MESSAGES = 2;
+
+// Titles that indicate noise sessions (internal housekeeping)
+export const NOISE_TITLE_PREFIXES = ["Compaction", "compaction"];
+
+// ── Path resolution (seam-based, like stack_state.ts) ────────────────────────
+
+export function resolveCacheDir(): string {
+  const env = process.env.AMICODE_SESSION_RECAP_CACHE_DIR;
+  if (env && env.trim() !== "") return env.trim();
+  return path.join(os.homedir(), ".amico", "session-recaps");
+}
+
+export function resolveDbPath(): string {
+  const env = process.env.OPENCODE_DB;
+  if (env && env.trim() !== "" && env !== ":memory:") {
+    if (path.isAbsolute(env)) return env;
+    const xdgData = process.env.XDG_DATA_HOME || path.join(os.homedir(), ".local", "share");
+    return path.join(xdgData, "opencode", env);
+  }
+  const xdgData = process.env.XDG_DATA_HOME || path.join(os.homedir(), ".local", "share");
+  return path.join(xdgData, "opencode", "opencode.db");
+}
+
+// ── Cache ────────────────────────────────────────────────────────────────────
+
+function ensureCacheDir(): boolean {
+  try {
+    fs.mkdirSync(resolveCacheDir(), { recursive: true });
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+function cachePathFor(sessionId: string): string {
+  return path.join(resolveCacheDir(), `${sessionId}.json`);
+}
+
+export function readCachedRecap(sessionId: string): SessionRecap | null {
+  try {
+    const raw = fs.readFileSync(cachePathFor(sessionId), "utf8");
+    return JSON.parse(raw) as SessionRecap;
+  } catch {
+    return null;
+  }
+}
+
+export function writeCachedRecap(recap: SessionRecap): void {
+  try {
+    ensureCacheDir();
+    const tmp = cachePathFor(recap.session_id) + ".tmp";
+    fs.writeFileSync(tmp, JSON.stringify(recap, null, 2), "utf8");
+    fs.renameSync(tmp, cachePathFor(recap.session_id));
+  } catch {
+    // Cache write failure is non-fatal
+  }
+}
+
+// ── Filtering (pure, testable) ───────────────────────────────────────────────
+
+/** Filter sessions per the issue's acceptance criteria. */
+export function filterCandidates(
+  sessions: SessionRow[],
+  currentSessionId: string | undefined,
+  assistantCountFn: (sessionId: string) => number,
+): SessionRow[] {
+  const candidates: SessionRow[] = [];
+  for (const s of sessions) {
+    if (currentSessionId && s.id === currentSessionId) continue;
+    if (NOISE_TITLE_PREFIXES.some(p => s.title.startsWith(p))) continue;
+    if (assistantCountFn(s.id) < MIN_ASSISTANT_MESSAGES) continue;
+    candidates.push(s);
+    if (candidates.length >= MAX_RECAPS) break;
+  }
+  return candidates;
+}
+
+// ── Mechanical recap extraction (pure, testable) ─────────────────────────────
+
+/** Extract key outcomes from assistant text parts. */
+export function extractOutcomes(assistantTexts: string[]): string[] {
+  const outcomes: string[] = [];
+  for (const text of assistantTexts) {
+    // Look for fidelity values
+    const fMatch = text.match(/[Ff]\s*[=:≈]\s*(0\.9\d+|1\.0)/);
+    if (fMatch && !outcomes.some(o => o.includes("F="))) {
+      outcomes.push(`F=${fMatch[1]}`);
+    }
+
+    // Look for iteration counts
+    const iterMatch = text.match(/(\d+)\s*iteration/i);
+    if (iterMatch && !outcomes.some(o => o.includes("iter"))) {
+      outcomes.push(`${iterMatch[1]} iterations`);
+    }
+
+    // Look for infidelity
+    const infMatch = text.match(/infidelity\s*[=:≈]\s*([\d.]+[eE][-+]?\d+)/);
+    if (infMatch && !outcomes.some(o => o.includes("infidelity"))) {
+      outcomes.push(`infidelity ${infMatch[1]}`);
+    }
+  }
+  return outcomes;
+}
+
+/** Compose a recap string from user prompts and extracted outcomes. */
+export function composeRecapText(userTexts: string[], outcomes: string[]): string | null {
+  if (userTexts.length === 0) return null;
+
+  const firstPrompt = userTexts[0].slice(0, 120).replace(/\n/g, " ");
+  const promptSummary = userTexts.length > 1
+    ? `${firstPrompt}... (+${userTexts.length - 1} more turns)`
+    : firstPrompt;
+
+  const parts = [promptSummary];
+  if (outcomes.length > 0) {
+    parts.push(outcomes.join(", "));
+  }
+
+  return parts.join(". ");
+}
+
+// ── Markdown composition (pure, testable) ────────────────────────────────────
+
+export function composeMarkdown(recaps: SessionRecap[]): string {
+  const lines = ["## Recent sessions (last 7 days)", ""];
+
+  for (const r of recaps) {
+    const date = new Date(r.created);
+    const dateStr = date.toLocaleDateString("en-US", { month: "short", day: "numeric" });
+    const timeStr = date.toLocaleTimeString("en-US", { hour: "2-digit", minute: "2-digit", hour12: false });
+    const titlePart = r.title && r.title !== "New Session" ? `**${r.title}** — ` : "";
+    lines.push(`- **${dateStr}, ${timeStr}** — ${titlePart}${r.recap}`);
+  }
+
+  return lines.join("\n");
+}
+
+// ── DB interaction (Bun-only, isolated for testability) ──────────────────────
+
+/** Lazy-loaded Database class from bun:sqlite. Null on non-Bun runtimes. */
+let SqliteDatabase: (new (path: string, opts?: { readonly?: boolean }) => any) | null = null;
+try {
+  // bun:sqlite is a Bun built-in — this import resolves only in the Bun runtime
+  // (opencode's embedded plugin runner). Under Node/vitest it throws and we
+  // gracefully degrade (buildRecentSessionsBlock returns null).
+  SqliteDatabase = require("bun:sqlite").Database;
+} catch {
+  // Not running in Bun — DB access unavailable
+}
+
+/** Query user-prompt and assistant texts from a session. Returns null if DB unavailable. */
+function querySessionContent(db: any, sessionId: string): { userTexts: string[]; assistantTexts: string[] } | null {
+  try {
+    // Get user text parts
+    const userParts = db.prepare(`
+      SELECT p.data FROM part p
+      JOIN message m ON p.message_id = m.id
+      WHERE p.session_id = ?
+        AND json_extract(m.data, '$.role') = 'user'
+        AND json_extract(p.data, '$.type') = 'text'
+      ORDER BY p.time_created ASC
+    `).all(sessionId) as Array<{ data: string }>;
+
+    const userTexts: string[] = [];
+    for (const row of userParts) {
+      try {
+        const parsed = JSON.parse(row.data) as { text?: string };
+        if (parsed.text && parsed.text.trim()) {
+          userTexts.push(parsed.text.trim());
+        }
+      } catch { /* skip */ }
+    }
+
+    // Get assistant text parts (latest first)
+    const assistantParts = db.prepare(`
+      SELECT p.data FROM part p
+      JOIN message m ON p.message_id = m.id
+      WHERE p.session_id = ?
+        AND json_extract(m.data, '$.role') = 'assistant'
+        AND json_extract(p.data, '$.type') = 'text'
+      ORDER BY p.time_created DESC
+      LIMIT 10
+    `).all(sessionId) as Array<{ data: string }>;
+
+    const assistantTexts: string[] = [];
+    for (const row of assistantParts) {
+      try {
+        const parsed = JSON.parse(row.data) as { text?: string };
+        if (parsed.text) assistantTexts.push(parsed.text);
+      } catch { /* skip */ }
+    }
+
+    return { userTexts, assistantTexts };
+  } catch {
+    return null;
+  }
+}
+
+// ── Public API ───────────────────────────────────────────────────────────────
+
+/**
+ * List recent sessions, generate/cache recaps, compose a markdown block.
+ * Returns null if there are no recent sessions, DB is unavailable, or on error.
+ */
+export function buildRecentSessionsBlock(currentSessionId?: string): string | null {
+  if (!SqliteDatabase) return null;
+
+  const dbPath = resolveDbPath();
+  if (!fs.existsSync(dbPath)) return null;
+
+  let db: any;
+  try {
+    db = new SqliteDatabase(dbPath, { readonly: true });
+  } catch {
+    return null;
+  }
+
+  try {
+    const cutoff = Date.now() - RECAP_WINDOW_DAYS * 24 * 60 * 60 * 1000;
+
+    // Query recent sessions: non-subagent, non-archived, within window
+    const sessions = db.prepare(`
+      SELECT id, title, parent_id, time_created, time_updated
+      FROM session
+      WHERE parent_id IS NULL
+        AND time_archived IS NULL
+        AND time_created > ?
+      ORDER BY time_created DESC
+      LIMIT ?
+    `).all(cutoff, MAX_RECAPS + 5) as SessionRow[];
+
+    if (sessions.length === 0) return null;
+
+    // Filter candidates
+    const assistantCountFn = (sessionId: string): number => {
+      const row = db.prepare(`
+        SELECT COUNT(*) as cnt FROM message
+        WHERE session_id = ? AND json_extract(data, '$.role') = 'assistant'
+      `).get(sessionId) as { cnt: number } | null;
+      return row?.cnt ?? 0;
+    };
+
+    const candidates = filterCandidates(sessions, currentSessionId, assistantCountFn);
+    if (candidates.length === 0) return null;
+
+    // Generate recaps (cached or fresh)
+    const recaps: SessionRecap[] = [];
+    for (const s of candidates) {
+      const cached = readCachedRecap(s.id);
+      if (cached) {
+        recaps.push(cached);
+        continue;
+      }
+
+      const content = querySessionContent(db, s.id);
+      if (!content || content.userTexts.length === 0) continue;
+
+      const outcomes = extractOutcomes(content.assistantTexts);
+      const recapText = composeRecapText(content.userTexts, outcomes);
+      if (!recapText) continue;
+
+      const recap: SessionRecap = {
+        session_id: s.id,
+        title: s.title,
+        created: new Date(s.time_created).toISOString(),
+        recap: recapText,
+        summarized_at: new Date().toISOString(),
+      };
+
+      writeCachedRecap(recap);
+      recaps.push(recap);
+    }
+
+    if (recaps.length === 0) return null;
+
+    return composeMarkdown(recaps);
+  } catch (e) {
+    console.error(`[session-recap] failed: ${e instanceof Error ? e.message : String(e)}`);
+    return null;
+  } finally {
+    try { db.close(); } catch { /* ignore */ }
+  }
+}