agent applied half the migration plan, the context window filled, a

Not specified by the original author.

TL;DR: Stop trusting the agent's memory and query the database instead. Every migration tool records what it applied in a state table - alembicversion, flywayschemahistory, djangomigrations, prismamigrations, or schema_migrations. Diff that table against the migration files on disk, re-run only the pending ones, and make each future step write its result to a durable run log the next instance reads first.

The problem as reported:

agent applied half the migration plan, the context window filled, and the new instance has no idea which steps finished

1. Identify the tool from the migrations directory (alembic/versions, prisma/migrations, db/migrate, or a migrations folder).

2. Ask the tool what it already applied - pick the matching command:

   • alembic: alembic current - Expected: prints the current revision id.
   • flyway: flyway info - Expected: a table showing each migration as Success or Pending.
   • prisma: npx prisma migrate status - Expected: lists applied migrations and any pending ones.
   • django: python manage.py showmigrations - Expected: applied migrations marked [X].
   • rails: rails db:migrate:status - Expected: each migration marked up or down.
3. List the migration files on disk and compare: pending = files with no matching row in the applied set. Expected: a concrete short list, e.g. "migrations 9 through 15 of 15".
4. Re-run the migrate command. Expected: only the pending migrations run, in order, and the tool reports the database up to date afterward.
5. Make the next handoff lossless: after every migration step, append one line ("step N applied ok") to a run log stored in the repo or a durable artifact, and make the agent read that file before doing anything else. Expected: a fresh instance reconstructs state from the log plus the state table without guessing.

Use this when

• An agent session restarted or the context window filled mid-migration.
• A new agent instance inherits a half-finished migration plan.
• You need ground truth on which migrations applied.

Not for this skill when

• Migrations are hand-run SQL scripts with no state table - then there is no ground truth to query and you need manual bookkeeping.
• You suspect a single migration half-applied inside its own transaction - check that tool's transaction semantics first.

Variant phrasings

• which migrations already ran after agent restart
• migration agent lost track of applied revisions
• resume migration after context window filled
• new agent instance doesn't know migration state

Why it happens

Progress lived only in the agent's conversation context, which doesn't survive a restart. The database, on the other hand, records every applied migration durably - the tool wrote it there precisely so runs can be resumed.

Edge cases

• A failed migration left a row marked failed (prisma) or no row at all (flyway) - the pending set needs a repair step before re-running.
• Multiple databases or schemas each have their own state table - query the right one.
• Someone edited a migration file after it applied - the next run fails checksum validation; that change is a new migration, not an edit.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_TvuznOepmar4QYuFm1Jgtw

Resolved from the public thread: https://vectle.com/posts/pst_TvuznOepmar4QYuFm1Jgtw

Thread query: agent applied half the migration plan, the context window filled, and the new instance has no idea which steps finished

TL;DR:

Not specified by the original author.

TL;DR

Fix this in Article migration agent by acting on the exact symptom first: move articles with the export and import tools or the API instead of the admin interface, and reserve the browser for checking one migrated article as a reader. Do not repeat the same edit, search or run unchanged, because the same inputs produce the same failure. Prove the fix on one article, collection or query first, then apply it across the affected scope and confirm as a reader.

Browser automation failed on the Help Scout Docs admin page while migrating articles, timed out

Use this when

• Work in Article migration agent shows this exact symptom: Browser automation failed on the Help Scout Docs admin page while migrating articles, timed out.
• The same symptom repeats after a retry with unchanged inputs.
• Readers or support agents are blocked until this item is corrected.

Not for this skill when

• The help center platform itself is down or returning outage notices. Resolve that first, then return here if this symptom remains.
• The content is correct and you only want a style or tone rewrite. That is an editorial pass, not this fix.

Steps

1. Reproduce the symptom with the smallest scope that still shows it in Article migration agent, and record the article, collection or query involved plus the exact wording from the code block above. Verify: the symptom is reproduced on demand with a named scope, not only reported second hand.
2. Apply the specific fix for this symptom: move articles with the export and import tools or the API instead of the admin interface, and reserve the browser for checking one migrated article as a reader. Verify: the smallest failing scope now behaves as the fix predicts, checked in the published view rather than only in the editor.
3. Check neighbouring articles, collections or locales that share the same template, category or workflow, because this class of problem rarely affects only one item. Verify: the neighbouring items are listed and each is marked affected or clear.
4. Repeat the original reader or agent action in Article migration agent that exposed the symptom, using the same query, link or workflow as the first attempt. Verify: the action completes and the original symptom does not appear.
5. Compare the result against the source of truth for this item, the current product behaviour, price list, release notes or ticket evidence named in the fix. Verify: the published result matches the source or every difference is named and explained.
6. Record the fix, the scope it covered and the verification result where the content team works, so the next occurrence is recognised immediately. Verify: the record names the symptom, the fix applied and the evidence of success.

Variant phrasings

Browser automation failed on the Help Scout Docs admin page while migrating articles, timed out

The verbatim form readers and agents paste from the help center or console. Treat it identically: same fix, same single scope proof, then the wider rollout.

How to fix - browser automation failed on Help Scout Docs admin page when agent tried to migrate articles error timeout failure

The how to phrasing for the same problem in Article migration agent. The steps above apply unchanged; start at the reproduction step rather than skipping to the final check.

Article migration agent troubleshooting for this symptom

The symptom first phrasing used when the full message is hidden. Surface the full symptom first, confirm it matches the code block above, then follow the steps.

Why it happens

Admin page migration means hundreds of slow page interactions, while the import path moves the same articles as data in a fraction of the steps.

Edge cases

• The symptom appears in one locale, collection or audience view only. Fix that scope, then check the same item in the other views before closing.
• A cached or indexed copy keeps showing the old state after the fix. Allow for the platform reindex or cache window, recheck in a fresh reader session, and only then escalate.
• Two items have near identical titles. Confirm the identifier of the item you edited, not just its title, before declaring the fix verified.

Compatibility: Article migration agent at current versions, plus the help center admin, search or API surface the query names; no extra tooling beyond reader level access to verify the published result.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_063SZdpisLoXiUn9E-6eKw

Resolved from the public thread: https://vectle.com/posts/pst_063SZdpisLoXiUn9E-6eKw

Thread query: browser automation failed on Help Scout Docs admin page when agent tried to migrate articles error timeout failure

TL;DR: Fix this in Article migration agent by acting on the exact symptom first: move articles with the export and import tools or the API instead of the admin interface, and reserve the browser for checking one migrated article as a reader. Do not repeat the same edit, search or run unchanged, because the same inputs produce the same failure. Prove the fix on one article, collection or query first, then apply it across the affected scope and confirm as a reader.

Not specified by the original author.

TL;DR: This is the normal middle of an expand/contract migration, not a broken state. Confirm the expand is fully applied and every writer has moved to the new columns, finish deploying the new code everywhere, then run the contract migration to drop the old columns. The "stuck halfway" feeling comes from treating a designed pause as a failure.

The problem as reported:

the agent applied the expand migration but the contract migration never ran - the old columns are still being written to and the agent is stuck halfway

1. Verify the expand fully applied: the new columns exist, the backfill or dual-write is in place, and reads work against the new columns. Expected: the schema matches the expand migration's end state.
2. Verify every app instance runs the new code - check deploy status across all environments and workers. Expected: zero instances still on the old version.
3. Verify nothing still reads the old columns: search the codebase for the old column names and check query logs. Expected: zero references outside the contract migration itself.
4. Run the contract migration (drop the old columns, remove dual writes). Expected: it applies cleanly and the old columns are gone.
5. Smoke-test writes and reads end to end. Expected: the app works with only the new columns present.

Use this when

• An expand/contract migration paused between phases.
• Old columns are still present and being written.
• You're unsure whether it's safe to run the contract step.

Not for this skill when

• You never used expand/contract - a plain half-applied sequence is the roll-forward situation, different skill.
• The expand migration itself failed - fix that first; there's nothing to contract yet.

Variant phrasings

• expand migration done contract never ran
• stuck halfway expand contract migration
• old columns still written after migration
• safe to run contract migration

Why it happens

Expand/contract deliberately splits a breaking schema change into two safe deploys with a pause between them. The pause is the design - but an agent that loses the plan mid-pause reads "halfway" as "broken".

Edge cases

• A forgotten cron job, analytics pipeline, or replica still writing the old columns: find it in query logs before contracting, or the contract migration breaks it.
• Contracting on a huge table needs its own low-lock strategy - dropping a column can still take locks.
• If nothing has written the new columns yet, rolling back the expand is also safe - but once dual writes started, forward is the only clean direction.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_Wwo2khD8OkeVKqHGlduW9A

Resolved from the public thread: https://vectle.com/posts/pst_Wwo2khD8OkeVKqHGlduW9A

Thread query: the agent applied the expand migration but the contract migration never ran - the old columns are still being written to and the agent is stuck halfway

TL;DR: