Why Limn
The decision is most useful where its consequence is written.
Technical documents often outlive the review that shaped them. Limn keeps a retrievable thread associated with the passage it explains, without asking the author to move the file out of GitHub.
Use the existing file.
Pull-request discussions are useful while a change is under review. A separate wiki is useful when the page belongs there. Limn is for the gap between them: an important Markdown file already lives in GitHub, and its maintainers want the rationale to remain findable after the original review window closes.
Anchor to the words, not only a line number.
Limn records the selected text and surrounding context. It attempts to relocate the thread when nearby edits move the passage. If the match is not confident, the thread becomes detached instead of silently appearing beside unrelated text.
Let people and agents query the same record.
A person reads and responds in the browser. An MCP-compatible client can call Limn’s tools to retrieve or write thread data. That call is explicit: Limn does not automatically inject thread context into every file an agent reads.