files changed" tab empty: diff too large to display error

TL;DR

GitHub will not render a diff past its size limit in the browser, but every change is still in the repo. Fetch the PR branch locally with git and review the diff in directory-sized chunks. Start with the file list and stat summary so you know what you are walking before you read it.

Sorry, we could not display the entire diff because it was too large.

1. Check out the PR locally. With the GitHub CLI: gh pr checkout 123. Expected: the working branch switches to the PR branch; git status shows the branch name.
2. List every changed file: git diff --name-only main...HEAD. Expected: one file path per line, even when the web tab shows nothing. Use the PR's real base branch in place of main.
3. Get the size summary: git diff --stat main...HEAD | tail -3. Expected: a totals line like 142 files changed, 8031 insertions(+).
4. Review one directory at a time: git diff main...HEAD -- path/to/dir. Expected: only that directory's hunks print.
5. Skip generated noise: git diff main...HEAD -- . ':!package-lock.json' ':!*.min.js'. Expected: the diff without lockfiles and minified bundles.
6. If the PR is too big to review in one pass, ask the author to split it into stacked PRs.

Use this when

• The Files Changed tab shows the diff-too-large notice
• The tab is empty or partial on a PR with a huge diff
• An agent needs the full diff that the web UI refuses to render

Not for this skill when

• The tab loads but stops listing files at 3000 (that is the file-count cap, a different limit)
• The PR really has no changes (an empty diff is correct)
• You need GitHub's inline comment UI; this skill gets you the diff content, not the review UI

Variant phrasings

• "github PR files changed tab not showing large diff"
• "sorry we could not display the entire diff because it was too large"
• "pull request diff too large to view in browser"
• "files changed empty on huge PR"

Why it happens

GitHub renders diffs server-side for the web UI and refuses diffs past a line-count threshold to protect page loads. The git objects are all still there; only the web rendering gives up. A local clone applies the same diff with no cap, so the content is always recoverable.

Edge cases

• The REST diff endpoint has its own cap and returns 406 with Sorry, the diff exceeded the maximum number of lines (3000) past it. Use a local clone, not the API, for oversized diffs.
• If git diff main...HEAD prints nothing, you are on the wrong base or the PR branch is not checked out. Verify with git log --oneline -3 and git branch --show-current.
• Single huge files (generated bundles, data dumps) can push a small PR over the limit; review those by exclusion and ask the author to stop committing them.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_KONSxN7LIhAl4PvBecgaBQ