Jev glossary
PatternsFan-out pattern
Speculative fan-out
Ask every question the system might need in one request (including ones only some branches use), and let code discard the rest.
- Category
- Patterns
- Also known as
- Fan-out pattern
- Reading time
- 1 min
- Related terms
- 4
- Directory entries
- 6
- Docs
- docs.typesafe.ai
- Added
- 2026-09-24
Definition
The fan-out pattern sends many questions in a single call and lets code decide what is relevant. The ticket-triage example asks a Choice category plus four speculative Score and Noul judgments, then escalates bugs above severity 1.5 with reproduction above 0.6 and flags refunds above 0.7.
Questions run in parallel, so adding them barely changes response time; the cost is the input tokens for each speculative question on every call. Fan out on questions several branches can reuse rather than on everything a workflow might ask.
Tagspatternsbatching
Related terms
Definitions that connect to this one.
Speculative questionA question whose answer only matters on some code paths, asked anyway because questions are cheap and parallel.PatternsParallel questionsBatching many questions into one request instead of many calls, which is dramatically cheaper and faster with identical answers.PatternsContext windowThe 64k-token budget covering state plus all questions, with a 32k sub-budget for state plus the longest question.API & ModelsInput tokensThe tokens billed on every request: state plus questions, including speculative questions your code ignores.API & Models
From the Jev directory
Directory entries that go deeper on this term.
Ask everything the system might need in one request, then let code throw away what it does not use. The ticket-triage example sends a category plus four speculative questions in parallel.
Jev Practices & PatternsDocs#official#patterns#batching
Official
Architectural patterns for System One systems: speculative fan-out, confidence-gated routing, composite scoring, and intent routing.
Jev Practices & PatternsDocs#official#patterns#architecture
Official
wangkuangkuang's Python MCP bridge to Jev: three official question types plus compare, verify, and batch classify, with a one-command installer that writes client config for Claude Code, Pi, Cursor, OpenCode, or Codex.
Jev Agents & MCP#community#mcp#python
Community
Semantic search over GitHub's Terms of Service: one request ranks all 218 lines with a Choice while a Noul checks whether the document contains an answer at all, including when it should say no.
Jev CookbooksDocs#official#cookbook#search
Official
Reconstruct Markdown from unformatted text in two requests: 16 Noul line-pair questions stitch split sentences, then 62 questions classify each block's type and companions.
Jev CookbooksDocs#official#cookbook#formatting
Official
A 13-question regulatory briefing that shows batching every question into one call is 12.2x cheaper and 10x faster with no change in answers.
Jev CookbooksDocs#official#cookbook#batching
Official
From the Jev AI model community
Posts from builders shipping with Jev right now.