project-nomad/admin/app/controllers
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
..
benchmark_controller.ts fix(benchmark): surface a clear reason when leaderboard submission fails (#1138) 2026-08-04 03:38:38 +00:00
chats_controller.ts fix(security): SSRF validation for map downloads and error sanitization (CWE-918, CWE-209) (#552) 2026-04-21 14:26:28 -07:00
collection_updates_controller.ts fix(security): path traversal and SSRF protections from pre-launch audit 2026-03-11 14:08:09 -07:00
conditions_controller.ts Add offline FDA drug reference (labels, interaction view, conditions, remedies) (#1040) 2026-08-04 03:38:33 +00:00
creator_packs_controller.ts feat(creator-packs): gated per-creator video packs, offline via Kiwix (#1106) 2026-08-04 03:38:27 +00:00
docs_controller.ts fix(Docs): fix doc rendering 2025-07-11 15:31:07 -07:00
downloads_controller.ts fix(downloads): add retry button and resource download link for failed downloads (#1059) 2026-08-04 03:37:31 +00:00
drug_reference_controller.ts Add offline FDA drug reference (labels, interaction view, conditions, remedies) (#1040) 2026-08-04 03:38:33 +00:00
easy_setup_controller.ts feat(AI): enable remote AI chat host 2026-04-03 14:26:50 -07:00
home_controller.ts Add offline FDA drug reference (labels, interaction view, conditions, remedies) (#1040) 2026-08-04 03:38:33 +00:00
maps_controller.ts fix(maps): warn when world basemap missing instead of silent grey map (#1104) 2026-08-04 03:38:29 +00:00
nomad_md_controller.ts feat(AI): nomad.md for custom instructions (#1127) 2026-08-04 03:38:33 +00:00
ollama_controller.ts feat(AI): budget the prompt and actually set the context window (#1253) 2026-09-29 15:54:41 -07:00
openapi_controller.ts fix(UI): add API reference to Settings sidebar 2026-08-04 03:38:40 +00:00
rag_controller.ts feat(rag): add subject/collection organization to knowledge base (#1063) 2026-08-04 03:37:42 +00:00
settings_controller.ts feat(AI): budget the prompt and actually set the context window (#1253) 2026-09-29 15:54:41 -07:00
supply_depot_controller.ts feat: supply depot 2026-06-23 04:46:45 +00:00
system_controller.ts feat(supply-depot): add uninstall for curated apps (#1006) 2026-06-23 04:47:05 +00:00
zim_controller.ts feat(zim): add zim uploader in content manager 2026-06-23 04:47:08 +00:00