Source Grading

Grade every source before citing a claim from it, using this scale. Record the grade next to the source in the source list (Step 3 of SKILL.md).

Grades

• A — Primary, authoritative. Original data/docs/announcement from the entity the claim is about (official documentation, a company's own filing/announcement, the actual research paper, a firsthand account/interview with a direct participant).
• B — Primary, independent. Firsthand reporting/analysis by an independent party with direct access (a journalist who obtained documents, an independent benchmark someone ran themselves, a practitioner's own writeup of their own experience).
• C — Secondary, reputable. A summary/analysis by a source with a track record of accuracy, citing its own sources (a reputable publication citing the primary source, a well-regarded technical blog that shows its work).
• D — Secondary, unclear provenance. Summarizes or claims something without clearly citing where it came from; may still be useful as a lead to find the primary source, but don't cite its claims directly without corroboration.
• F — Unreliable. Anonymous/unverifiable claims, content with an obvious undisclosed conflict of interest relevant to the claim (e.g. a vendor's marketing page as the sole source for a competitive comparison), or a source with a known track record of inaccuracy on this topic.

Rules of use

• A-grade and B-grade sources can support a claim on their own. C-grade sources are strongest when corroborated by at least one other independent source. D-grade sources should not be the sole support for a claim in the final brief — use them to find a better source, or explicitly flag the claim as weakly-sourced if none exists.
• F-grade sources are not cited as support for a claim, ever — they can only be mentioned if the brief is specifically discussing misinformation/the existence of a claim, clearly labeled as such.
• Grade the source, not the claim's plausibility — a source doesn't get a better grade because you happen to agree with what it says. This is exactly the bias the disconfirming-evidence search in SKILL.md Step 2 is designed to counteract.
• Recency matters independently of grade: an A-grade source from 3 years ago on a fast-moving topic (pricing, product features, personnel) needs a freshness check even though its grade doesn't change.
• Note conflicts of interest even on otherwise well-graded sources (e.g. a company blog post is A-grade for "what the company announced" but should be flagged, not treated as neutral, for "is this product actually good").