rony-chat-bot/data/docs/README.md
Victor Hugo Vargas 129809067b feat(rag): hybrid retrieval, reference documents, and vendor sampling
Answers were short, sometimes in the wrong language, and occasionally about
projects that do not exist. Measured on a 20-question battery against the real
corpus in both Spanish and English, this takes grounded content from 3/10 to
9/10 and language matching from 7/10 to 10/10.

Retrieval
- Fuse FTS5 keyword search with dense vectors via Reciprocal Rank Fusion.
  Both halves are load-bearing: the corpus is English and visitors ask in
  Spanish, so the meaningful words score zero. "paga" appears 0 times in a
  document that says "Payments: Stripe" — the question "¿Con qué se paga en la
  tienda de ropa?" retrieved nothing at all. Embeddings put all three of that
  project's chunks on top. RRF ranks by agreement rather than comparing a BM25
  score against a cosine, quantities with no shared scale.
- internal/embed: OpenAI-compatible embeddings client, unit-normalised so a
  dot product is the cosine. Reorders by the response `index` field.
- Store a content hash beside each vector and skip rows where it no longer
  matches the chunk. Chunk ids survive body edits, so without this an edited
  document keeps serving embeddings that describe text that is gone —
  reproduced live by changing a payment provider and watching the old one keep
  coming back.
- Degrade to keyword-only when the embedder is down instead of failing.

Reference documents that are not projects
- Index `.mdx` alongside `.md`, and split sources into projects (announced in
  the catalogue) and reference material (retrievable, never listed). A CV is
  what someone deciding whether to hire actually reads, and it was unreachable
  while it lived only in the Astro site — but filing it under projects made
  the bot list "cv" as one of Victor's works.
- Skip each directory's README. `data/projects/README.md` was being indexed,
  so the catalogue injected into every prompt announced "README" and
  "README.es" as projects of Victor's.
- Exclude frontmatter from retrieval. It is dense metadata in a very short
  chunk, which makes it a magnet for short queries: a CV's `location:` field
  answered "¿Dónde ha trabajado Victor?" with a city instead of a work history.
- Split oversized sections at `###` before falling back to byte offsets. A CV's
  Experience section is a list of jobs, and size-splitting cut one mid-word,
  stranding the employer's name in the previous chunk.

Prompt and sampling
- Inject the full project catalogue every turn. Top-K search returns the best
  matching sections, so "list every project" cannot be answered from retrieval
  alone, and a small model asked to enumerate from partial hits invents the
  rest. ~10 tokens per project; this is what stopped the invented names.
- Wire the sampling parameters the model authors publish (top_k, top_p, min_p,
  repeat_penalty, presence_penalty) through config to llama.cpp. Leaving them
  at llama.cpp's defaults produced 16-token stub answers.
- Localised system prompt selected by detected language. The English prompt
  plus "reply in the user's language" answered 1/5 Spanish questions in
  Spanish; few-shot examples fixed the language but got copied verbatim into
  real answers.
- Fold compaction's system notes into the leading system message. Gemma's chat
  template rejects a system message that is not first, and the whole request
  failed with HTTP 400 the moment compaction fired.

Configuration and docs
- context_size 4096, down from 8192. The largest prompt this bot ever built
  over 20 real requests was 1255 tokens, compaction starts at ~3070, and the
  cut saved 212 MB resident with zero truncations and identical throughput.
- Correct the RAM figures throughout. They were measured with a GPU absorbing
  llama.cpp's buffers; on a GPU-less VPS those come out of system RAM, which
  is 1.1 GB more for qwen2.5-3b and 2.8 GB more for granite. Both READMEs
  still started gemma-3-1b while the config defaulted to qwen, and neither
  started the embedder at all.

Measured on the 2-core, 8 GB CPU-only target: 3.64 GB LLM + 0.91 GB embedder
+ 0.02 GB bot, 21.0 tok/s steady state.

Known and unfixed, so they are not re-filed as new bugs: the model reads dates
out of the CV correctly but does the arithmetic on them wrong, and "¿Dónde ha
trabajado Victor?" still answers with projects rather than employers, though
"¿En qué empresas ha trabajado?" works.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-07-30 15:45:36 -07:00

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Markdown

# Reference Documents
Material that is **about you but is not a project**: your CV, an about page, a
FAQ, a talk abstract. Everything here is indexed and retrievable, and never
announced in the project catalogue.
Accepts `.md` and `.mdx`.
## Why this directory exists
`data/projects/` is advertised. The bot injects the full list of what lives
there into every prompt, so visitors get told those are your projects.
Your CV is the document that answers what someone considering hiring you
actually asks — "does he know Kubernetes?", "where has he worked?", "how long
was he at that job?" — and none of it is retrievable while it lives only in
your site. But it is not a project, and putting it in `data/projects/` makes
the bot cheerfully list "cv" as one of your works. Hence the split.
## The contents are gitignored
Only this README is tracked. What goes here is personal (a CV) or a symlink to
a path that only exists on your machine, and neither travels well in a repo.
Set it up on each install:
```bash
ln -s ../../../portfolio/src/content/cv/cv.mdx data/docs/cv.mdx
./bin/chat-bot reindex
```
A symlink rather than a copy so there is one file to keep current — edit the
CV in your site, re-run `reindex`, and the bot is up to date.
## Configuration
```yaml
rag:
data_path: ./data/projects # projects → listed in the catalogue
docs_path: ./data/docs # this directory → retrievable, never listed
```
Leave `docs_path` empty to turn the whole thing off.
## Notes
- Frontmatter is excluded from retrieval. It is dense metadata in a very short
chunk, which makes it a magnet for short queries — a CV's `location:` field
was answering *"where has Victor worked?"* with a city instead of his work
history.
- Long sections split at `###` headings, so each job in a CV's Experience
section stays one chunk instead of being cut mid-sentence.
- This README is skipped by the indexer, as is the one in `data/projects/`.