Reverse-compression (inflation) is the failure mode where LLM output expands without adding information
Type: note · Status: seedling · Tags: kb-design, learning-theory
Compression removes redundancy to preserve information. Reverse-compression is the inverse: expanding a compact signal into verbose prose without adding extractable structure. This is the common failure mode of vibe-noting — a human offers a one-sentence insight, the agent builds a whole article grounded in its training knowledge, and the result reads like depth but teaches the reader nothing beyond the seed.
Why epiplexity is the right measure
What counts as "adding information" depends on who you measure against. Three candidate tests, each more precise than the last:
- Does the body contain claims not in the title? Insufficient — an LLM can generate novel-looking claims by connecting the seed to common knowledge.
- Does the body contain information not derivable from the title combined with the LLM's training knowledge? Well-defined but wrong — it measures novelty relative to the model, not usefulness to the reader.
- Does the body make structure accessible to the reader that wasn't before? The right question — usefulness is relative to the audience, not the source.
Epiplexity — epistemic complexity extractable by a bounded observer — formalizes test 3. Connecting to common knowledge can raise epiplexity — when the connection is surprising to the reader, when the reader lacks that specific piece, or when the juxtaposition makes a pattern visible that the reader wouldn't have extracted on their own. But when the connections are obvious to the audience, the elaboration adds tokens without adding epiplexity. A reverse-compressed article is one where the structure was already accessible to its readers without the article.
How a linked KB resists reverse-compression
In a linked KB, each link can carry the reader to a node with its own epiplexity — a practitioner report with quantified results, a formal framework, a prior argument with independent evidence. The network is where epistemic complexity accumulates, not the prose of any single note.
But this resistance requires that links are load-bearing — the linked notes must actually contribute to the argument. A note full of "see also" links to tangentially related material is still reverse-compressed; the links are decorative, not structural. The test: remove the links — does the argument collapse, or does it read identically?
Toward a validation gate
A reverse-compression check is semantic, not structural — it can't be grepped. One heuristic worth testing manually before mechanizing into /validate:
For the intended reader (an agent or human with access to this KB and general training knowledge), does the note's body — including the nodes its links reach — make structure accessible that wasn't before? If the answer is no, the note is reverse-compressed regardless of its length or link count.
Relevant Notes:
- vibe-noting — context: the inflation failure mode this note names and analyzes
- information value is observer-relative — grounds: epiplexity formalizes what "adds information for a bounded observer" means
- distillation — contrasts: distillation compresses while preserving essential structure; reverse-compression expands while adding none
- Epiplexity paper — source: the formal measure of extractable structure for bounded observers
- link contracts framework — enables: articulated link relationships are what make links load-bearing rather than decorative
- skills derive from methodology through distillation — contrasts: distillation is the productive inverse — compressing while preserving; reverse-compression is the failure mode — expanding while adding nothing