feat(ai): card narratives regenerated when the commit set changes

src/lib/ai/narrate.ts

@@ -0,0 +1,128 @@
+import "server-only";
+
+import { getAdminPb } from "@/lib/pb/admin";
+import { getProvider, getSystemPrompt, AiError } from "@/lib/ai";
+import { PROMPT_VERSION } from "@/lib/ai/preamble";
+import { aiConfigured } from "@/lib/ai/settings";
+import {
+  buildNarrativePrompt,
+  narrativeIsStale,
+  shaFingerprint,
+  type NarrativeCommit,
+} from "@/lib/ai/narrative";
+import type { CardRecord, CommitRecord } from "@/lib/pb/types";
+
+export interface NarrateResult {
+  considered: number;
+  written: number;
+  skipped: boolean;
+  error?: string;
+}
+
+/**
+ * Regenerate narratives for a project's cards where the commit set has changed.
+ *
+ * Never throws, for the same reason as summariseProject: narratives are an
+ * enhancement over a board that already works.
+ *
+ * One request per card, not batched. A narrative is a few paragraphs of
+ * connected prose about one piece of work; batching would mean the model
+ * writing several unrelated updates in one response, and the index-matching
+ * problem from Plan 3b with far more text at stake per mismatch.
+ */
+export async function narrateProject(projectId: string): Promise<NarrateResult> {
+  if (!(await aiConfigured())) {
+    return { considered: 0, written: 0, skipped: true };
+  }
+
+  const pb = await getAdminPb();
+
+  const cards = await pb.collection("cards").getFullList<CardRecord>({
+    filter: `project = "${projectId}" && archived = false`,
+    fields: "id,title,description,narrative,narrative_version,narrative_shas",
+  });
+
+  let provider;
+  let system: string;
+
+  try {
+    provider = await getProvider();
+    system = await getSystemPrompt();
+  } catch (error) {
+    return {
+      considered: 0,
+      written: 0,
+      skipped: true,
+      error: error instanceof AiError ? error.message : "AI is not configured",
+    };
+  }
+
+  let considered = 0;
+  let written = 0;
+  let lastError: string | undefined;
+
+  for (const card of cards) {
+    const commits = await pb.collection("commits").getFullList<CommitRecord>({
+      filter: `card = "${card.id}" && is_merge = false`,
+      sort: "authored_at",
+      fields: "sha,subject,summary,authored_at",
+    });
+
+    const shas = commits.map((c) => c.sha);
+
+    const stale = narrativeIsStale(
+      {
+        narrative: card.narrative ?? "",
+        version: card.narrative_version ?? 0,
+        shas: card.narrative_shas ?? "",
+      },
+      shas,
+      PROMPT_VERSION
+    );
+
+    if (!stale) continue;
+
+    // A card with no commits gets no narrative. Writing one would be invention,
+    // and an empty card showing confident prose about work that has not started
+    // is exactly the failure this phase must not have.
+    if (commits.length === 0) continue;
+
+    considered += 1;
+
+    const items: NarrativeCommit[] = commits.map((c) => ({
+      sha: c.sha,
+      subject: c.subject || "",
+      summary: c.summary || "",
+      authoredAt: c.authored_at,
+    }));
+
+    try {
+      const result = await provider.complete({
+        system,
+        user: buildNarrativePrompt(
+          { title: card.title, description: card.description ?? "" },
+          items
+        ),
+        maxTokens: 4096,
+      });
+
+      if (!result.text) {
+        lastError = "The provider returned an empty narrative";
+        continue;
+      }
+
+      await pb.collection("cards").update(card.id, {
+        narrative: result.text.slice(0, 8000),
+        narrative_version: PROMPT_VERSION,
+        narrative_shas: shaFingerprint(shas),
+      });
+      written += 1;
+    } catch (error) {
+      lastError = error instanceof AiError ? error.message : "Request failed";
+      // A non-retryable failure will fail identically for every other card.
+      if (error instanceof AiError && !error.retryable) break;
+    }
+  }
+
+  return { considered, written, skipped: false, error: lastError };
+}

src/lib/git/ingest.ts

@@ -184,6 +184,11 @@ export async function ingestProject(
   try {
     const { summariseProject } = await import("@/lib/ai/summarise");
     await summariseProject(project.id);
+
+    // Narratives prefer the one-liners, so summarisation must run first or the
+    // first narrative after a push would be written from raw subjects.
+    const { narrateProject } = await import("@/lib/ai/narrate");
+    await narrateProject(project.id);
   } catch (error) {
     console.error(`[ingest] summarisation failed for ${project.id}`, error);
   }