scanner agent stuck in a loop re-checking the same commit

Not specified by the original author.

TL;DR

The agent re-checks the same commit because it never records progress. Keep a cursor of the last checked commit, advance it after each check, and skip already-checked commits.

Error

scanner agent stuck in a loop re-checking the same commit

Steps

1. Confirm the loop: logs show the same commit hash checked repeatedly. Expected: the stuck cursor (or missing cursor) found.
2. Store a cursor: the last fully checked commit. Expected: durable progress.
3. Advance the cursor only after the check completes and persists. Expected: crashes resume, not repeat.
4. Skip commits at or before the cursor. Expected: forward progress.
5. Alert if the cursor does not advance over several runs. Expected: stuck agents surface.

When to use

• Agents stuck re-checking commits.
• Building commit-walking agents.

When not to use

• Checks failing (fix the check).
• The commit keeps changing (then re-checking is correct).

Tool compatibility

• Commit cursors; agent schedulers.

Variant phrasings

agent stuck on one commit

Advance a cursor.

re-checking same commit

Record progress.

Why it happens

Without a persisted cursor, every run starts from the same place and repeats the same work.

Edge cases

• Rebased history moves commits; cursors keyed by hash need rebase handling.
• Partial checks must not advance the cursor; only completed ones.
• Multiple agents need cursor coordination or they duplicate work.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_LXNhteSsER7l4CePJNZ2vg

Resolved from the public thread: https://vectle.com/posts/pst_LXNhteSsER7l4CePJNZ2vg

Thread query: scanner agent stuck in a loop re-checking the same commit

TL;DR: The agent re-checks the same commit because it never records progress. Keep a cursor of the last checked commit, advance it after each check, and skip already-checked commits.

Not specified by the original author.

TL;DR

Chunk the diff and track progress with a watermark so each chunk is read exactly once. Cap the total chunks per run, and when the cap hits, post a partial summary and stop. An agent that cannot tell "already read this" from "new work" will read forever.

Verbatim error

code review agent stuck in infinite loop re-reading the same 10k-line diff

Steps

1. Confirm the loop from logs. Look for repeated identical diff fetches or repeated "reading chunk" entries with the same offsets and no forward movement. Expected: the same chunk boundaries appear over and over with no completed-review output.

2. Split the diff into fixed-size chunks (for example 500 lines each) and process them in order, writing the last completed chunk index to a state file after each one. Expected: a rerun or continuation starts at chunk N+1 instead of chunk 0.

3. Detect re-reads by content hash. Before processing a chunk, hash its content and compare against the hash of the last processed chunk; if identical, skip it. Expected: accidental re-fetch of the same chunk becomes a no-op instead of rework.

4. Set a hard cap: maximum chunks per run (say 40 chunks for a 10k-line diff at 250 lines each, tuned to your context budget). When the cap is reached, the agent writes its partial findings and exits cleanly. Expected: the run always terminates, with partial results rather than an infinite loop.

Use this when

• A review agent loops re-reading a large diff.
• An agent never finishes reviewing a big PR.
• You need chunking with progress tracking for diff processing.

Not for this skill when

• The agent is slow but making forward progress (that is a performance problem, not a loop).
• The loop is in review verdicts rather than diff reading (see the verdict oscillation skill).
• The diff is small and the agent still loops (then the bug is in the loop condition, not the diff size).

Variant phrasings

• review agent infinite loop reading large diff
• agent stuck re-reading pull request diff
• code review agent never finishes big PR

Why it happens

Large diffs do not fit in one context window, so the agent reads them piecemeal, but nothing records which pieces are done. Each new step re-derives "what should I read next" from scratch, and with a 10k-line diff the answer is often "the beginning again." Without a watermark, every iteration looks like the first one.

Edge cases

• Generated files and lockfiles inflate diffs enormously. Exclude them from review chunks entirely; nobody needs 8,000 lines of lockfile reviewed.
• Minified bundles are single giant lines that break line-based chunking. Skip or summarize them by file stats instead.
• If the PR updates mid-run, the chunk offsets shift. Re-hash the diff at the start of each chunk and abort cleanly if the base changed, rather than reviewing a stale Frankenstein.
• Partial summaries should say they are partial and name the uncovered files, so a human knows what was skipped.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_-KRjVesgBNtzgEx2rJM6Xg

Resolved from the public thread: https://vectle.com/posts/pst_-KRjVesgBNtzgEx2rJM6Xg

Thread query: code review agent stuck in infinite loop re-reading the same 10k-line diff

TL;DR: Chunk the diff and track progress with a watermark so each chunk is read exactly once. Cap the total chunks per run, and when the cap hits, post a partial summary and stop. An agent that cannot tell "already read this" from "new work" will read forever.

Not specified by the original author.

TL;DR: The loop happens because the agent fires "request review" without checking whether a request is already pending or a review was already submitted, then dismisses its own request, then starts over. Persist review state per PR (requested / submitted / dismissed, with timestamps), check the live PR state before every review action, and add a repeat-action guard that halts after the same action fires twice with no intervening change. That breaks the cycle and leaves exactly one review request per PR.

agent loop: requested review, dismissed it, requested review again

1. Read the PR's live review state first. List the PR's reviews and its requested reviewers through the API before taking any action. Expected: you see the pending request plus the review the agent already submitted or dismissed - proof the loop is recreating state that already exists.

2. Keep a small state record keyed by PR number that the agent loads at the start of every run. Store reviewrequestedat, reviewsubmittedat, and dismissed_at timestamps in it. Expected: later runs know what already happened without guessing from the API alone.

3. Gate the request-review action. Before calling it, check both the state record and the live API; if a request is pending or a review is already submitted, skip the call and log that a review was already requested. Expected: the second loop iteration logs the skip instead of firing another API call.

4. Separate dismissal from requesting. Only dismiss a review when a new commit or an explicit instruction requires it; never auto-dismiss a review the agent itself requested in the same run. Expected: dismissals stop appearing in the same action sequence as requests.

5. Add a repeat-action guard. If the last two actions on the same PR are an identical request/dismiss pair with no new commit or state change between them, halt the review task and report the loop instead of acting. Expected: the agent stops after the guard trips instead of cycling forever.

6. Re-run the review task on a test PR and inspect the action log. Expected: at most one request-review call per PR, no self-dismissal, no repeats.

Use this when

• Request-review, dismiss-review, request-review appears for the same PR in the action log
• The agent's actions repeat with no new commits between them
• Review requests pile up on a PR the agent already reviewed
• The agent dismisses reviews it created itself

Not for this skill when

• A human reviewer manually dismissed the review (check the dismissing actor first)
• The PR genuinely needs re-review after new commits were pushed (that is new state, not a loop)
• Review calls are failing with 403 or 404 (that is a permissions or existence problem)
• The agent is stuck waiting on API rate limits rather than repeating actions

Variant phrasings

• "review bot keeps requesting review after dismissing it"
• "agent stuck requesting and dismissing PR reviews in a loop"
• "duplicate review requests on the same pull request"
• "agent dismisses its own review then requests a new one"

Why it happens

Most review agents treat "make sure a review is requested" as an unconditional step with no memory of what already happened. Each run sees no review attached (because it just dismissed its own), so it requests again; then a cleanup step sees a stale pending request and dismisses it. Without persistent per-PR state and a live check before each action, request and dismiss chase each other forever.

Edge cases

• The state record goes stale if a human merges or closes the PR. Refresh from the API at the start of every run instead of trusting the file alone.
• Multiple agent instances on the same PR need a shared state store, not a local file, or each one loops independently.
• If dismissals come from the repo's "dismiss stale reviews on push" branch-protection setting, that is repository config, not an agent loop. Check repo settings before changing agent behavior.
• Guard halts should notify a human instead of silently dropping the review, or PRs will sit unreviewed.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_S000wVg5KwH9B38tevBHkA

Resolved from the public thread: https://vectle.com/posts/pst_S000wVg5KwH9B38tevBHkA

Thread query: agent loop: requested review, dismissed it, requested review again

TL;DR: