`, `og:title`), date (meta tags, JSON-LD, `<time>`), body (strip scripts/nav), soft-404 detection. - If article body is empty, is a soft-404, or is too old: trace as `filtered_empty` / `filtered_too_old` and skip. **Phase B — Classify/summarize batch in parallel** (`JoinSet`): - Check rate limit before classifying (waits up to 60s, then errors). - Send article (title + first 500 chars of body) + categories + "Autre" to LLM. LLM returns `{title, summary, category}`. If the title was empty, the LLM also generates one. - **LLM call logged** with full prompt/response/timing. - **`assign_category()`** helper: validates category, falls back to "Autre" if category is unknown or full. If "Autre" is also full, drops the article. - Add the article to `article_scraped`, increment `filled_counts`, increment `source_counts[domain]`. **Early exit**: after each batch, if total articles across all categories ≥ `(num_categories + 1) × max_items_per_category`, stop and move to Phase 2. **Trace flush**: all pending traces accumulated during Phase 1 are batch-inserted into `article_history` after Phase 1 completes. --- ## Phase 2: Web Search Fallback **Skipped if all user-defined categories are already filled to `max_items_per_category`.** ### 2a. Compute category gaps - For each user category: `needed = max_items_per_category - already_filled` - Only proceed if any category needs more articles. ### 2b. Choose path: Brave Search or LLM web search The path is selected by the `settings.use_brave_search` flag. --- ### Path A: Brave Search (`use_brave_search = true`) #### 2b-A. Call Brave Search API - Resolve and decrypt the user's Brave Search API key (error if not configured). - Query: `"{settings.theme} actualites"`, up to 20 results, filtered by `max_age_days`. #### 2c-A. Filter Brave results Each result URL passes through **`filter_phase2_url()`**: 1. **Homepage filter** — drop URLs with path `/` or empty (`filtered_homepage`) 2. **Cross-phase dedup** — drop URLs already in `seen_urls` (`filtered_cross_phase_dedup`) 3. **Article history** — check hash in DB, drop if seen before (`filtered_history`) 4. **Source diversity** — drop if `source_counts[domain] >= max_articles_per_source` (`filtered_diversity`) Accepted URLs are added to `seen_urls`. All rejections are traced. Traces are **batch-flushed** after this filter step. #### 2d-A. Scrape + classify Brave results (batched) Same batch loop as Phase 1b, using `settings.batch_size`: - **Phase A**: scrape batch in parallel, trace failures as `source_type: "brave_search"`. - **Phase B**: classify/summarize in parallel (same LLM call + logging as Phase 1). - **`assign_category()`** used identically to Phase 1. - Source domain tracked in `source_counts`. - **Early exit** at `max_total` articles. - Traces are batch-flushed after this loop. --- ### Path B: LLM Web Search (`use_brave_search = false`) #### 2b-B. LLM web search pass - Check rate limit. - Build search prompt with theme, categories, gap counts ("find N articles for category_1, M for category_2"). - Send search prompt to LLM (using `model_websearch`). LLM returns structured JSON: `{category_0: [{title, url, summary}], category_1: [...]}` - **LLM call logged** with full prompt/response/timing. #### 2c-B. Filter LLM search results Same **`filter_phase2_url()`** logic as Path A (homepage, cross-phase dedup, history, diversity). Accepted URLs are added to `seen_urls`. Traces are **batch-flushed** after this filter step. #### 2d-B. Scrape LLM search results (sequential) - For each accepted item: call `scrape_single_article` (SSRF check, 15s timeout, 5MB limit). - If scrape fails or article is too old/empty: trace as appropriate and skip. - Otherwise: keep the LLM-provided title and summary (no re-classification LLM call). Add to `article_scraped`, increment `source_counts[domain]`. - Traces are batch-flushed after all items are processed. --- ## Save + Record - **Error if empty** — if all scraped article lists are empty, return an error. - **Order sections** — user-defined categories first (in order), then "Autre" if non-empty. - **Sanitize** — strip `\u0000` null bytes from JSON (PostgreSQL rejects them in JSONB). - **Save synthesis** — insert into `syntheses` table with `job_id`, `week` (ISO week), `sections` (JSONB), `status: completed`. - **Record used articles** — for each article in the final synthesis, build a trace with `status: "used"`, `synthesis_id`, and the correct `source_type` (`personalized_source`, `brave_search`, or `web_search` inferred from `url_source`). Batch-insert into `article_history`. --- ## Shared Helpers - **`build_trace_entry()`** — constructs an `ArticleHistoryEntry` from an `ArticleTrace` struct (replaces the old 11-positional-parameter `trace_article` function). Never writes to DB directly; caller accumulates in `pending_traces`. - **`assign_category()`** — validates LLM-returned category against the classification list, falls back to "Autre", drops article if "Autre" is also full. - **`filter_phase2_url()`** — async helper applying homepage/dedup/history/diversity filters for Phase 2 (both Brave and LLM paths). - **`scrape_single_article()`** — thin wrapper around `scraper::scrape_url` returning `(body_text, page_title, final_url, drop_reason)`. - **`hash_article_url()`** — normalizes a URL (strips fragments, UTM params, trailing slashes, lowercases) then SHA-256 hashes it for history lookup.

# Synthesis Generation Pipeline — Full Algorithm ## Startup & Background Tasks - **Session cleanup**: an hourly background task deletes expired DB sessions (`db::sessions::delete_expired`). - **Job store TTL**: expired job entries (older than 1 hour) are cleaned up via `JobStore::cleanup_expired`. ## Generation Lifecycle `POST /api/v1/syntheses/generate` creates a job in the `JobStore`, then spawns two nested tasks: - Inner task: wraps `run_generation` in a **15-minute `tokio::time::timeout`**. If the timeout fires, sends an `Error` progress event and releases the user lock. - Outer task: monitors the inner task's `JoinHandle` for panics. If the inner task panics, sends an `Error` progress event and releases the user lock. Progress is streamed to clients via a `tokio::sync::watch` channel (SSE endpoint subscribes to it). --- ## Initialization 1. **Load user settings** from DB (categories, provider, models, max_items, batch_size, etc.) 2. **Cleanup** — delete old article history entries (>N days, dropped only) + truncate old LLM call logs 3. **Validate** — if no categories configured, the only available category will be "Autre". 4. **Load user sources** (personalized URLs like `https://openai.com/blog`) 5. **Resolve LLM provider** — decrypt user's API key, create provider instance (`Arc`) 6. **Resolve models** — research model + web-search model (user override or admin default) 7. **Setup rate limiter** — per-user or global provider limiter 8. **Initialize tracking structures** — `article_scraped` (category→articles), `source_counts` (per-domain article count), `url_source` (per-article source), `filled_counts` (per-category article count), `seen_urls` (cross-phase dedup), `classification_categories` (user categories + "Autre") 9. **Batch trace buffer** — `pending_traces: Vec` accumulates all article history writes; flushed with `db::article_history::batch_insert_entries` at phase boundaries (not per article). --- ## Phase 1: Personalized Sources **Skipped entirely if user has 0 sources.** ### 1a. Extract article links from source pages and filter against article history - Query `article_history` for the last source used. Reorder the personalized sources so that the first source is the one following the last source used (rolling window). - Fetch source pages with bounded concurrency of **5** (hardcoded `max_concurrent = 5`): - If `use_llm_for_source_links` enabled: send HTML `` + first 8000 chars of `` to LLM → extract all article URLs up to a maximum of **15**, with the most recent first. If the LLM call fails, fall back to HTML parsing as described below. - **LLM call logged** with full prompt/response/timing - Otherwise: parse HTML `` links, filter by same-domain, non-homepage path, exclude `/tag/`, `/login/`, `/contact/`, `/presentation/`, `/newsletter/`, static assets, etc., and keep only the first **15** links found. - **SSRF check** performed on each source URL before fetching (rejects private/loopback IPs). - Deduplicate candidate URLs (case-insensitive, cross-source via `seen_urls`). - **Filter against article history** — hash each URL (normalized: lowercase, strip fragments/UTM params/trailing slashes), batch-query `article_history` → remove matches. - Trace dropped articles as `status: filtered_history` (flushed immediately after this filter step). - **Shuffle** remaining candidates to interleave articles from different sources. - Track url → source in `url_source`. ### 1b. Scrape, classify, and summarize articles (batched) Processing happens in batches of `settings.batch_size` (minimum 1). For each batch: **Batch assembly**: pull up to `batch_size` candidates from the iterator, skipping any where `source_counts[domain] >= max_articles_per_source` (traced as `filtered_diversity`). **Phase A — Scrape batch in parallel** (`JoinSet`): - SSRF check (no private IPs), 15s timeout, 5MB body limit. - HTML parsing heuristics for title (``, `og:title`), date (meta tags, JSON-LD, `<time>`), body (strip scripts/nav), soft-404 detection. - If article body is empty, is a soft-404, or is too old: trace as `filtered_empty` / `filtered_too_old` and skip. **Phase B — Classify/summarize batch in parallel** (`JoinSet`): - Check rate limit before classifying (waits up to 60s, then errors). - Send article (title + first 500 chars of body) + categories + "Autre" to LLM. LLM returns `{title, summary, category}`. If the title was empty, the LLM also generates one. - **LLM call logged** with full prompt/response/timing. - **`assign_category()`** helper: validates category, falls back to "Autre" if category is unknown or full. If "Autre" is also full, drops the article. - Add the article to `article_scraped`, increment `filled_counts`, increment `source_counts[domain]`. **Early exit**: after each batch, if total articles across all categories ≥ `(num_categories + 1) × max_items_per_category`, stop and move to Phase 2. **Trace flush**: all pending traces accumulated during Phase 1 are batch-inserted into `article_history` after Phase 1 completes. --- ## Phase 2: Web Search Fallback **Skipped if all user-defined categories are already filled to `max_items_per_category`.** ### 2a. Compute category gaps - For each user category: `needed = max_items_per_category - already_filled` - Only proceed if any category needs more articles. ### 2b. Choose path: Brave Search or LLM web search The path is selected by the `settings.use_brave_search` flag. --- ### Path A: Brave Search (`use_brave_search = true`) #### 2b-A. Call Brave Search API - Resolve and decrypt the user's Brave Search API key (error if not configured). - Query: `"{settings.theme} actualites"`, up to 20 results, filtered by `max_age_days`. #### 2c-A. Filter Brave results Each result URL passes through **`filter_phase2_url()`**: 1. **Homepage filter** — drop URLs with path `/` or empty (`filtered_homepage`) 2. **Cross-phase dedup** — drop URLs already in `seen_urls` (`filtered_cross_phase_dedup`) 3. **Article history** — check hash in DB, drop if seen before (`filtered_history`) 4. **Source diversity** — drop if `source_counts[domain] >= max_articles_per_source` (`filtered_diversity`) Accepted URLs are added to `seen_urls`. All rejections are traced. Traces are **batch-flushed** after this filter step. #### 2d-A. Scrape + classify Brave results (batched) Same batch loop as Phase 1b, using `settings.batch_size`: - **Phase A**: scrape batch in parallel, trace failures as `source_type: "brave_search"`. - **Phase B**: classify/summarize in parallel (same LLM call + logging as Phase 1). - **`assign_category()`** used identically to Phase 1. - Source domain tracked in `source_counts`. - **Early exit** at `max_total` articles. - Traces are batch-flushed after this loop. --- ### Path B: LLM Web Search (`use_brave_search = false`) #### 2b-B. LLM web search pass - Check rate limit. - Build search prompt with theme, categories, gap counts ("find N articles for category_1, M for category_2"). - Send search prompt to LLM (using `model_websearch`). LLM returns structured JSON: `{category_0: [{title, url, summary}], category_1: [...]}` - **LLM call logged** with full prompt/response/timing. #### 2c-B. Filter LLM search results Same **`filter_phase2_url()`** logic as Path A (homepage, cross-phase dedup, history, diversity). Accepted URLs are added to `seen_urls`. Traces are **batch-flushed** after this filter step. #### 2d-B. Scrape LLM search results (sequential) - For each accepted item: call `scrape_single_article` (SSRF check, 15s timeout, 5MB limit). - If scrape fails or article is too old/empty: trace as appropriate and skip. - Otherwise: keep the LLM-provided title and summary (no re-classification LLM call). Add to `article_scraped`, increment `source_counts[domain]`. - Traces are batch-flushed after all items are processed. --- ## Save + Record - **Error if empty** — if all scraped article lists are empty, return an error. - **Order sections** — user-defined categories first (in order), then "Autre" if non-empty. - **Sanitize** — strip `\u0000` null bytes from JSON (PostgreSQL rejects them in JSONB). - **Save synthesis** — insert into `syntheses` table with `job_id`, `week` (ISO week), `sections` (JSONB), `status: completed`. - **Record used articles** — for each article in the final synthesis, build a trace with `status: "used"`, `synthesis_id`, and the correct `source_type` (`personalized_source`, `brave_search`, or `web_search` inferred from `url_source`). Batch-insert into `article_history`. --- ## Shared Helpers - **`build_trace_entry()`** — constructs an `ArticleHistoryEntry` from an `ArticleTrace` struct (replaces the old 11-positional-parameter `trace_article` function). Never writes to DB directly; caller accumulates in `pending_traces`. - **`assign_category()`** — validates LLM-returned category against the classification list, falls back to "Autre", drops article if "Autre" is also full. - **`filter_phase2_url()`** — async helper applying homepage/dedup/history/diversity filters for Phase 2 (both Brave and LLM paths). - **`scrape_single_article()`** — thin wrapper around `scraper::scrape_url` returning `(body_text, page_title, final_url, drop_reason)`. - **`hash_article_url()`** — normalizes a URL (strips fragments, UTM params, trailing slashes, lowercases) then SHA-256 hashes it for history lookup.