Commit Graph

2 Commits

Author SHA1 Message Date
Jake Turner
5c97bf605a fix(AI): stop <think> output leaking into titles, chips, and the RAG query (#1254)
ThinkTagSplitter was wired into both streaming paths but neither
non-streaming one, and every ancillary call goes through non-streaming
chat(). So a reasoning tasks model put its reasoning transcript into the
sidebar title, into the suggestion chips, and — worst — into the string
that gets embedded and sent to Qdrant, silently corrupting retrieval for
the rest of the conversation. splitThinkTags() already existed and was
already unit tested; it just had no production callers.

Fixed in three layers:

1. Strip at the transport. New normalizeNonStreamed() in think_stream.ts
   merges structured reasoning (native `thinking`, /v1 `reasoning`) with
   anything the splitter pulls out of inline tags, and both _chatNative
   and _chatCompat now return through it. That covers every caller at
   once, including the legacy controller path and the eval harness.

2. Suppress at the source. _chatNative and _chatStreamNative forwarded
   `think` only when truthy, so `think: false` was never sent and Ollama
   left reasoning on for capable models. Guard is now definedness. This
   also fixes the ai.autoThinking=off setting, which had no effect on
   the native streaming transport.

3. Guard the call sites. Title, suggestions, and query rewrite now pass
   think:false plus thinkingCapable (from the memoized capability check,
   so no extra round-trip), and handle an empty-after-strip result. The
   rewrite matters most: QUERY_REWRITE_MAX_TOKENS caps it at 120, which
   a reasoning model burns entirely on thinking, so stripping alone
   would have turned a corrupt query into an empty one. It now falls
   back to the raw user message instead of embedding "".

Verified: think_stream.spec.ts 17/17 (6 new cases, including the
truncated-mid-thought case that drives the fallback), typecheck clean,
full test:unit failures byte-identical to the pre-change baseline.
2026-09-29 15:54:41 -07:00
Jake Turner
9a95f7b2b8 feat(AI): budget the prompt and actually set the context window (#1253)
Chat was run through Ollama's OpenAI-compatible /v1 endpoint, which has no
context-size field, so the num_ctx we sent was silently discarded and the
entire NUM_CTX_LADDER was dead code. Every conversation ran at the backend
default and was truncated from the middle (where history and
retrieved context actually sit). Measured with identical ~7k-token prompts:
2,060 tokens processed against 7,049 on the native endpoint, and with the
needed fact in the discarded middle the old path hallucinated a plausible
wrong number.

Transport: add a native /api/chat path using the already-installed ollama
package, sending a real options object (num_ctx, num_predict, temperature,
seed) plus keep_alive. The OpenAI path is still used for LM Studio and llama.cpp,
minus the ineffective num_ctx and with include_usage so both paths return
prompt token counts. /api/show is now read for trained context, parameter
size, quantization and any modelfile num_ctx. The <think> stream normalizer
moves to app/utils/think_stream.ts so both transports share it; it gains a
flush() that fixes a dangling partial tag being dropped at end of stream.

Token accounting: replace chars/N with a structural segmenter scaled by a
per-model factor learned by EWMA from the prompt_eval_count every response
already returned and threw away. End-to-end estimator error is 4.6% against
18-20% for a fixed divisor — qwen2.5 converges to k=1.26 where llama3 sits
at 1.00, so no single global constant serves both.

Context window: resolved once per model from trained context, the exact KV
cost derived from GGUF metadata (head_count_kv, not head_count — GQA makes
them differ 4x), and available VRAM, then memoized. Memoization is
load-bearing: asking for a different num_ctx makes Ollama unload and reload
the model, stalling the turn and discarding the KV cache. The floor never
overrides the model's trained ceiling — tinyllama trains to 2048, and a
blind 4096 floor pushes RoPE past anything the weights saw.

Prompt budget: planPrompt allocates explicitly instead of delegating
overflow to silent backend truncation — response reserve, then fixed blocks
(system and current query, never dropped), then RAG chunks whole and
best-first, then history in whole user+assistant turns, evicted newest-first
in blocks with an elision marker. Block eviction keeps the prefix stable for
several turns rather than shifting on every one.

KV-cache ordering: the per-turn retrieved block moves behind history to the
tail, so the stable prefix stays byte-identical turn to turn. At turn 14 of
a long conversation, prefill is 231ms at the tail against 539ms at the front
(~1ms/turn growth against ~25ms). The win is conditional — with a large
retrieved block and short history the two measure the same — so both
orderings ship behind RAG_PLACEMENT. The per-turn query rewrite also moves
to the tasks model; on a single-slot Ollama it was evicting the chat model's
cached prefix on every single turn.

Also: OLLAMA_CONTEXT_LENGTH and OLLAMA_KV_CACHE_TYPE=q8_0 on the container
(q8_0 is treated as headroom, never as a budgeting assumption, since
unsupported architectures fall back to f16 silently), a Context Window
setting in Settings > Models, and budget fields on PipelineTrace.

Eval: golden suites (--suite) so the new long_context goldens cannot move
the aggregates the committed baselines were recorded against, plus budget
and estimator-error metrics through the report path. Retrieval is unchanged
and eval:compare reports no metric outside the tolerance band; the
long_context suite scores correctness 1.000 with historyElided 0.500 (the
two eviction cases, by design). Unit tests 337 -> 386 passing, same 7
pre-existing failures.

Ingest-side CHAR_TO_TOKEN_RATIO is deliberately untouched: changing it
re-chunks the corpus and invalidates retrieval baselines, which belongs in
its own measured change.
2026-09-29 15:54:41 -07:00