AI Reddit comments without shadowban: the per-sub gate is the real risk

The advice you find on this topic almost always treats shadowban as one thing and tells you to space your posts out, age the account, and avoid VPNs. That is not wrong, but it misses the failure mode that actually kills a running AI-comment pipeline: per-subreddit gates that silently eat your comment with no API error, no banner, and no permalink to retry against. Those gates are local to the sub and they are detectable before you post if you stop trying to talk to the API and start reading the DOM of the logged-in page instead.

The five things people call “shadowban”

When someone in r/redditrequest or a sub-mod chat says they were shadow-banned, they almost always mean one of these. They produce identical symptoms (your comment seems to post, nobody replies, the permalink does not appear logged out) and have completely different fixes:

1. Sitewide shadowban. Account-level Reddit anti-abuse action. Logged out, your profile is empty. This is the only one of the five that is actually called a shadowban by Reddit internally.
2. Sub-level user ban or AutoMod author block. One sub has added your username to a ban list or to an AutoMod author: rule. Everything you write in that sub is removed before any human sees it.
3. AutoMod karma or age gate. The sub's AutoMod config has a min_karma, min_combined_karma, or min_account_age_days threshold you do not clear. Reddit's help center lists 1 to 7 days for general subs, 30 to 60 days for professional subs, and 60 to 120 days for crypto and finance.
4. Mod-approval-only mode. Often turned on temporarily during a sub drama. Every comment from every account is held until a mod approves it.
5. Crowd Control. Reddit's built-in safety setting collapses comments from accounts the community has not interacted with positively yet. Your comment is technically visible, but reordered into the bottom of the thread and grey-collapsed for everyone else.

For a pipeline that drafts and posts AI Reddit comments at scale, only the first one is genuinely about the account. The other four are per-subreddit. Treating them as a single problem is the reason most published advice does not survive contact with a real posting loop.

The signal you can actually read at posting time

Reddit does not expose an “is this account allowed to comment in this sub” endpoint. The new.reddit React app does not give you a clean DOM either; gate state is buried inside an event stream. Old.reddit.com is different. When a sub gates a logged-in user (any of mechanisms 2 through 4 above, and sometimes 5), the page renders normally but the comment area silently omits the textarea form. The rest of the thread is there. There is no error banner. There is no tooltip. The page just does not let you type.

The honest version of “avoid shadowbans” is to look for that absence before you draft anything. In scripts/reddit_browser.py the pipeline runs this locator on every thread before it touches the model:

# scripts/reddit_browser.py, line 413
has_comment_form = page.locator(
    ".commentarea .usertext.cloneable, "
    ".commentarea > form.usertext"
).count() > 0
if not has_comment_form:
    return {"ok": False, "error": "account_blocked_in_sub"}

That single check absorbs sub-level user bans, AutoMod karma and age gates, and mod-approval-only mode. It does not distinguish between them, and it does not need to. From a posting orchestrator's perspective, “your comment will not survive in this sub” is the only information that matters.

What the pipeline does next, and why it is irreversible

Detection is half the work. The other half is making sure the next cycle does not waste a candidate on the same sub. Two writes happen when account_blocked_in_sub comes back:

1. Candidate marked permanent failed. In scripts/post_reddit.py the constant _PERMANENT_CDP_ERRORS includes account_blocked_in_sub. The candidate row gets status='failed' with permanent=True, so Phase 0 salvage skips it forever.
2. Subreddit appended to subreddit_bans.comment_blocked. The function mark_comment_blocked in the same file writes a record {subreddit, reason, added_at, project} into the project's config.json. Every future drafting cycle reads that list and refuses to surface threads from those subs as candidates.

The design choice that matters here is the irreversibility. We do not mark the row pending and try later. We do not write a soft signal that a retry might recover. A sub that gated us once will gate us again at worse pacing, because the underlying state (karma, age, user ban) is unlikely to change in the next 24 hours. The cost of being wrong (one missed sub) is dramatically smaller than the cost of looping on a gated sub (3 wasted Claude sessions, polluted backfill, fake permalinks in the post log).

What it looks like end to end

A real run on a thread in a sub the account has never touched, where the sub turns out to have a karma gate we do not clear:

The cycle keeps going. The next two candidates in this batch are in different subs and post normally. The blocked sub is now gone from the drafter's universe for this project.

The actual size of the per-sub kill list

On this project, the live config.json has the following counts as of the date this page was written. The ratio is what you should plan around: the per-sub gate list is more than twice the size of the new-post block list, because comments attract Crowd Control and karma gates that thread posts often bypass.

What pacing actually buys you

Pacing is the standard recommendation in every other guide on this topic, and it does buy two real things: it keeps the account under Reddit's sitewide spam classifier (which scores posting velocity, link ratio, and duplication), and it keeps you under the rate-limit ceiling (HTTP 429 from the API, a transient state that unwinds in 60 seconds or so). The pipeline waits 3 minutes between posts within a single Claude session and pre-checks Reddit's quota before spawning a new session at all (_probe_reddit_quota in post_reddit.py).

What pacing does not buy you is anything against the per-sub gates. You can comment once a month and a sub with a 500-karma AutoMod rule will still filter you. You can rotate IPs and use mobile data and a sub that has banned your username will still hide every reply. The spam classifier and the per-sub gate are independent systems with independent fixes. Treating them as the same problem is what produces the “I slowed down and still got shadow-banned” reports you see on r/help every week.

A small thing other guides also miss

When a comment goes through the Reddit API and the sub has a karma gate, the POST returns a 200 with a permalink that points at a comment only you can see. From the API client's perspective, the post succeeded. The post log fills up with green checkmarks while every comment is actually filtered. We hit this in 2024 and built the DOM check specifically because it is the only signal at posting time that distinguishes “your comment landed” from “your comment was filtered before anyone saw it.” A second guard, no_permalink, covers the post-submit case where the comment we just sent does not show up under our username in the rendered DOM. Both errors are classified as permanent so the queue never retries them.

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