# Why numbered ledger ids (grounding research basis)

Design notes for anyone changing the citation instructions or the ledger
mechanics. The wording in SKILL.md is not arbitrary.

## The structural trick

Hallucinated citations happen when a model reconstructs a URL from memory. If
the only thing the model has to emit is a small integer it was handed at
retrieval time, there is nothing to reconstruct — a wrong id is detectable
(it's not in the ledger) and a wrong URL is impossible (the model never types
one; `render` does). This is the property Perplexity's product relies on, and
it's why the ledger, not the prose, owns the URL.

Consequence: **register at retrieval, render mechanically.** Any workflow that
lets the model type a URL into the Sources block gives the guarantee back.

## Cite while writing, not after

ALCE (arXiv:2305.14627) evaluates attribution for LLM answers and finds that
generating citations during composition, from numbered retrieved snippets,
produces materially better attribution than post-hoc citation insertion.
Post-hoc attribution invites the model to find a source that plausibly matches
a sentence it already wrote — which is exactly how a citation ends up
supporting something the page doesn't say.

Hence: cite per supported sentence, in-line, as the sentence is written. Never
a citation dump at the end of a paragraph or document.

## Verbatim quotes ground claims

WebGPT (arXiv:2112.09332) collects verbatim quotes at browse time and composes
answers from them. The practical rule for this skill: when a claim carries a
figure, date, name, or quantity, take it from the source's own words rather
than paraphrasing from a summary of a summary. Each summarization hop is a
chance for a number to drift.

## Formatting conventions

From Perplexity's leaked system prompts (jujumilk3/leaked-system-prompts) — the
conventions are worth copying because they're the ones users have been trained
to read:

- Marker directly after the terminal punctuation, no space: `water.[1]`
- Each id in its own brackets: `[1][2]`, not `[1, 2]`
- At most 3 ids per sentence — beyond that the citation stops identifying which
  source carries the claim
- Never cite a source not actually consulted
- Query classes that shouldn't be cited (translation, creative writing, casual
  chat) are exempted by instruction, not by a separate classifier

Perplexity forbids raw URLs in the answer because its UI renders source cards.
Hermes has no such UI layer in chat or in a written file, so this skill renders
the id → URL list explicitly instead.

## Related in-tree implementation

`tools/web_tools.py` grew an in-process version of this idea (a `url -> [n]`
registry plus citation guidance attached to tool results) in PR #44833. That
path grounds ad-hoc web answers automatically when it lands. This skill is the
portable half: it works with any retrieval source (browser, curl, CLIs, local
PDFs) and it persists the ledger to disk so multi-turn, multi-file, and
multi-subagent work keeps stable ids. The two can coexist — the ledger is the
source of truth for anything written to a file.