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Have the model synthesize a real title instead of truncating the body

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Every article title ended in "…" because there was never an actual
title — deriveTitle() just took the body's first paragraph and cut
it at 97 characters. The AI was never asked for a headline at all.

Both system prompts now ask for a response in three parts (headline,
then the article/recap, then tags), each separated by a delimiter.
parseResult() extracts all three; if the model doesn't follow the
format at all, it falls back to the old truncated-first-line
heuristic rather than breaking.

Delimiter matching is now a loose regex instead of an exact string —
production had already shown a small model reproducing "---TAGS---"
inexactly (e.g. "---\n\nTAGS---"), which the old exact-string split
missed entirely and leaked into the published body. Same tolerance
now applies to the new title delimiter.

publishCluster uses the synthesized title directly; publishEventRecap
uses it too, falling back to the previous "<event>: recap" format
only if the model returns an empty title.

Verified: exact-format output, sloppy-delimiter output, and
no-delimiter-at-all output all parse into sensible {title, body,
tags}; a full runSynthesisCycle pass against a mock provider
publishes an article with the real synthesized headline as its title.
This commit is contained in:
Claude
2026-07-27 14:29:45 +00:00
parent 1176bb4425
commit ecfcce9eb1
2 changed files with 49 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files
backend/src/pipeline/publish.ts
+4 -10
View File
@@ -36,12 +36,6 @@ function anyPushesToTopStories(items: ContentItem[]): boolean {
return items.some((item) => sources.getSource(item.sourceId)?.pushToTopStories ?? false);
}
/** Takes the first line of the synthesized body as a working title until a dedicated title-generation step exists. */
function deriveTitle(body: string): string {
const firstLine = body.split('\n')[0];
return firstLine.length > 100 ? firstLine.slice(0, 97) + '…' : firstLine;
}
/**
* Resolves the hero image for a regular (non-tweet) article: try the best candidate
* from the source items, download and locally host it; if there isn't one, fall back
@@ -362,7 +356,7 @@ export async function publishCluster(
const items = cluster.items;
const sourceNames = new Map(items.map((item) => [item.sourceId, sources.getSource(item.sourceId)?.name ?? 'Unknown source']));
const { body, tagLabels } = await synthesizeArticle(provider, settings.selectedModels.synthesis, items, sourceNames, settings);
const { title, body, tagLabels } = await synthesizeArticle(provider, settings.selectedModels.synthesis, items, sourceNames, settings);
const resolvedTags = [];
for (const label of tagLabels) {
@@ -418,7 +412,7 @@ export async function publishCluster(
const now = new Date().toISOString();
const article = articles.insertArticle({
title: deriveTitle(body),
title,
body,
heroImage,
video,
@@ -461,7 +455,7 @@ export async function publishEventRecap(
event: TrackedEvent,
constituents: MergedArticle[]
): Promise<MergedArticle> {
const { body, tagLabels } = await synthesizeRecap(provider, settings.selectedModels.synthesis, event.name, constituents, settings);
const { title, body, tagLabels } = await synthesizeRecap(provider, settings.selectedModels.synthesis, event.name, constituents, settings);
const resolvedTags = [];
for (const label of tagLabels) {
@@ -478,7 +472,7 @@ export async function publishEventRecap(
const now = new Date().toISOString();
return articles.insertArticle({
title: `${event.name}: recap`,
title: title || `${event.name}: recap`,
body,
heroImage,
video: null,
backend/src/pipeline/synthesis.ts
+45 -14
View File
@@ -3,8 +3,17 @@ import type { ContentItem, GlobalSettings, MergedArticle } from '../storage/db/t
import { DEFAULT_NUM_CTX, DEFAULT_NUM_PREDICT } from '../inference/ollama-provider.js';
import { logger } from '../storage/db/logs.js';
const TITLE_DELIMITER = '---TITLE---';
const TAG_DELIMITER = '---TAGS---';
// Small/quantized models don't always reproduce a literal delimiter exactly — extra
// dashes, an inserted blank line, different case (seen in production with the tag
// delimiter: "---\n\nTAGS---" instead of "---TAGS---", which an exact-string split
// missed entirely, leaking the raw delimiter text into the published body). Splitting
// on a loose regex instead tolerates that variance.
const TITLE_DELIMITER_RE = /-{2,}\s*TITLE\s*-{2,}/i;
const TAG_DELIMITER_RE = /-{2,}\s*TAGS\s*-{2,}/i;
// Ollama truncates prompts that don't fit its context window by keeping a small prefix
// and dropping everything else in the middle — silently, with no error, and with no
// regard for which sources end up cut (see ollama-provider.ts for the incident that
@@ -23,21 +32,25 @@ function capEntryText(text: string, budgetChars: number): string {
return text.length > budgetChars ? text.slice(0, budgetChars) + '…' : text;
}
const RECAP_SYSTEM_PROMPT_BASE = `You are a neutral news synthesis assistant. Given a chronological list of articles already published about an ongoing tracked event, write a single recap article that:
- Summarizes what has happened across the period covered, in chronological order
- Highlights the most significant developments rather than restating every article
- Stays neutral and factual, without editorializing
- Is 3-5 short paragraphs
const RECAP_SYSTEM_PROMPT_BASE = `You are a neutral news synthesis assistant. Given a chronological list of articles already published about an ongoing tracked event, write your response in exactly three parts, in this order:
After the recap, on a new line, write exactly "${TAG_DELIMITER}" followed by 2-4 short comma-separated topic/entity tags (e.g. proper nouns, named events) that this recap is about. If nothing salient qualifies, leave the tag line empty.`;
1. A short, specific headline for this recap (a single line, ideally under 12 words, no surrounding quotation marks, no trailing period).
2. On a new line, write exactly "${TITLE_DELIMITER}", then the recap article:
- Summarizes what has happened across the period covered, in chronological order
- Highlights the most significant developments rather than restating every article
- Stays neutral and factual, without editorializing
- Is 3-5 short paragraphs
3. On a new line after the recap, write exactly "${TAG_DELIMITER}" followed by 2-4 short comma-separated topic/entity tags (e.g. proper nouns, named events) that this recap is about. If nothing salient qualifies, leave the tag line empty.`;
const SYSTEM_PROMPT_BASE = `You are a neutral news synthesis assistant. Given summaries from multiple news sources describing the same event, write a single original article that:
- Attributes specific claims to the outlet that reported them, using each source's exact name as given below (e.g. if a source is labeled "Source 1 (Reuters)", write "Reuters reported..."). Never invent, guess, or substitute an outlet name that isn't one of the source names actually given below.
- Does not copy phrasing verbatim from any source
- Stays neutral and factual, without editorializing
- Is 2-4 short paragraphs
const SYSTEM_PROMPT_BASE = `You are a neutral news synthesis assistant. Given summaries from multiple news sources describing the same event, write your response in exactly three parts, in this order:
After the article, on a new line, write exactly "${TAG_DELIMITER}" followed by 2-4 short comma-separated topic/entity tags (e.g. proper nouns, named events) that this article is about. If nothing salient qualifies, leave the tag line empty.`;
1. A short, specific headline for this story (a single line, ideally under 12 words, no surrounding quotation marks, no trailing period, no site/outlet name).
2. On a new line, write exactly "${TITLE_DELIMITER}", then the article:
- Attributes specific claims to the outlet that reported them, using each source's exact name as given below (e.g. if a source is labeled "Source 1 (Reuters)", write "Reuters reported..."). Never invent, guess, or substitute an outlet name that isn't one of the source names actually given below.
- Does not copy phrasing verbatim from any source
- Stays neutral and factual, without editorializing
- Is 2-4 short paragraphs
3. On a new line after the article, write exactly "${TAG_DELIMITER}" followed by 2-4 short comma-separated topic/entity tags (e.g. proper nouns, named events) that this article is about. If nothing salient qualifies, leave the tag line empty.`;
// Admin-selectable presets (Merge tab, "Writing style") — appended to whichever base
// prompt applies. 'default' adds nothing: the base prompts above already describe the
@@ -58,10 +71,17 @@ function styleAddendum(settings: GlobalSettings): string {
}
export interface SynthesisResult {
title: string;
body: string;
tagLabels: string[];
}
/** Only used when the model doesn't follow the requested title/delimiter format at all — a real headline beats a truncated sentence fragment, but publishing with no title at all is worse than either. */
function fallbackTitle(body: string): string {
const firstLine = body.split('\n')[0];
return firstLine.length > 100 ? firstLine.slice(0, 97) + '…' : firstLine;
}
function buildPrompt(items: ContentItem[], sourceNames: Map<string, string>): string {
const budgetPerItem = Math.max(MIN_ENTRY_CHARS, Math.floor(MAX_INPUT_CHARS / items.length));
let truncated = 0;
@@ -88,13 +108,24 @@ function buildPrompt(items: ContentItem[], sourceNames: Map<string, string>): st
}
function parseResult(raw: string): SynthesisResult {
const [body, tagSection] = raw.split(TAG_DELIMITER);
const [beforeTags, tagSection] = raw.split(TAG_DELIMITER_RE);
const tagLabels = (tagSection ?? '')
.split(',')
.map((t) => t.trim())
.filter((t) => t.length > 0 && t.length < 60);
return { body: body.trim(), tagLabels };
const titleSplit = (beforeTags ?? raw).split(TITLE_DELIMITER_RE);
const titlePart = titleSplit[0];
// join() rather than titleSplit[1] in case the delimiter text somehow appears again
// inside the body itself — keeps that content rather than silently dropping it.
const bodyPart = titleSplit.length > 1 ? titleSplit.slice(1).join('') : undefined;
// If the title delimiter never showed up, the model didn't follow the requested
// format — treat the whole thing as body rather than mistaking the article itself
// for a "title", and fall back to the old truncated-first-line heuristic.
const body = (bodyPart ?? titlePart).trim();
const title = bodyPart !== undefined ? titlePart.trim() : fallbackTitle(body);
return { title, body, tagLabels };
}
export async function synthesizeArticle(