Cloudflare error 100117 during Custom Domain attachment — diag…

Agent diagnostic brief

Exact symptom

Cloudflare error 100117 during Custom Domain attachment

Where it has been observed

Cloudflare Workers; Wrangler Custom Domain deployment.

Likely distinct causes

A successful Worker upload implied the hostname was attached.
The existing web-origin records conflicted with Custom Domain ownership.

How to distinguish them

The intended Worker is attached to the exact host, Cloudflare-managed DNS exists, unrelated records are preserved, and trusted TLS plus canonical HTTP behavior pass.
Check Wrangler partial-deploy error against the same bounded execution window.
Check complete DNS readbacks against the same bounded execution window.
Check same-source redeploy against the same bounded execution window.
Check Custom Domain state against the same bounded execution window.
Check TLS and redirect matrix against the same bounded execution window.
Check live smoke against the same bounded execution window.
On Cloudflare Pages (not Workers), a 522 on a proxied hostname that was never attached as a custom domain is a separate failure with a different fix (see problem-pages-www-522-unattached).

Current approaches

Reconcile upload, domain, and DNS state before bounded recovery (solution-cloudflare-custom-domain-dns-conflict, revision 1).

Known obsolete approaches

Do not copy a historical workaround across versions without checking current product behavior.
Do not bypass permissions, security controls, or ownership boundaries merely to suppress the symptom.

Versions and freshness

Observed with Wrangler 4.131.0 on 2026-09-10; current Cloudflare docs rechecked 2026-09-11
Editorial and primary-source review date: 2026-09-11.
Source maintenance 2026-09-11: the API error reference linked by revision 1 returned HTTP 404; the current API troubleshooting page was added as a replacement source. The earlier link is kept for history.

What remains unknown

Behavior outside the stated products, versions, and environments remains unknown.
Independent reproduction by a different operator has not been established.

Deeper evidence

Problem

Cloudflare Custom Domain upload succeeds but DNS attachment fails

Observed symptom

The Worker version uploaded, but Custom Domain attachment failed because the target host still had externally managed DNS records.
The historical observation is same-operator evidence and does not establish general prevalence.

Operator goal

Complete deploy Worker to hostname with existing DNS records without mistaking process success for product acceptance.

Current understanding

The Worker version uploaded, but Custom Domain attachment failed because the target host still had externally managed DNS records.
Current primary material was reviewed on 2026-09-11; historical behavior remains bounded to Observed with Wrangler 4.131.0 on 2026-09-10; current Cloudflare docs rechecked 2026-09-11.

Known limitations

The observed result applies to one sanitized same-operator execution and the stated version boundary, not every environment.
Recheck product documentation and preserve the variable changed before generalizing the diagnosis.

Known negative results

Infer success or continue retrying from the mutation call alone. Result: Rejected because completion and exact target state were not established.
Read the complete bounded DNS inventory and compare exact record identity before choosing a separate authenticated recovery surface. Result: Readback proved no deletion had occurred and prevented accidental removal of unrelated records.
No same-operator execution in this release counts as an independent reproduction.
Applying Workers Custom Domain recovery to a Pages hostname that returns 522 does not help; that hostname only needs to be attached or redirected.

Primary and recurrence sources

Cloudflare API troubleshooting
Primary · Primary documentation · Date not supplied · Reviewed 2026-09-11 · Rights: allowed_to_summarize
Current primary material reviewed for claude-historical-corpus-1: Cloudflare API troubleshooting.
Cloudflare Workers Custom Domains
Primary · Primary documentation · Date not supplied · Reviewed 2026-09-11 · Rights: allowed_to_summarize
Current primary material reviewed for Historical Corpus 1: Cloudflare Workers Custom Domains.
Cloudflare Pages custom domains
Primary · Primary documentation · Date not supplied · Reviewed 2026-09-11 · Rights: allowed_to_summarize
Current primary material reviewed for claude-historical-corpus-1: Cloudflare Pages custom domains.
Wrangler environments documentation
Primary · Primary documentation · Date not supplied · Reviewed 2026-09-11 · Rights: allowed_to_summarize
Current primary material reviewed for Historical Corpus 1: Wrangler environments documentation.
Cloudflare API error reference
Supports · Primary documentation · Date not supplied · Reviewed 2026-09-11 · Rights: allowed_to_summarize
Current primary material reviewed for Historical Corpus 1: Cloudflare API error reference.
Cloudflare DNS record deletion API
Supports · Primary documentation · Date not supplied · Reviewed 2026-09-11 · Rights: allowed_to_summarize
Current primary material reviewed for Historical Corpus 1: Cloudflare DNS record deletion API.

Rights and provenance

Origin

Based on a real operator execution; identifying project details removed.

Rights

State: allowed_to_summarize
Review basis: Owner-authorized factual synthesis of the operator's own Claude-assisted execution, independently written from reviewed current primary sources; no transcript expression is published.

Editorial review date

2026-09-11

Known approaches

solution · Revision 1

Reconcile upload, domain, and DNS state before bounded recovery

Production corpus importer · 2026-09-11T10:30:00.000Z
Operator Knowledge for Agents editorial · Historical operator record · Digital source: trainedAlgorithmicMedia · Rights: owned

## Candidate action - Reconcile upload, domain, and DNS state before bounded recovery. Start by capturing the exact failed stage, current product version, and a bounded before-state. Apply only the smallest evidence-backed change, then repeat the original operation and verify its output independently. This is a candidate procedure supported by one same-operator execution, not a universal fix. ## Applicability - Use when the observed signature is: Cloudflare error 100117 during Custom Domain attachment. - Observed scope: Cloudflare Workers; Wrangler Custom Domain deployment. - Stop if the first failed stage or product boundary differs. ## Procedure - The intended Worker is attached to the exact host, Cloudflare-managed DNS exists, unrelated records are preserved, and trusted TLS plus canonical HTTP behavior pass. - Treat the version upload and the domain attachment as separate outcomes and reread both deployment and DNS state. Verify: Readback showed a live uploaded version but no accepted Custom Domain, preventing a false launch claim. - Remove only the owner-authorized conflicting web records after exact name/value review, preserve unrelated records, and redeploy the same committed source. Verify: Both Custom Domains attached and live TLS and redirect checks passed. - Compare the post-change result with the captured before-state and preserve exact readback evidence. ## Limitations - One same-operator execution does not establish cross-operator support. - The procedure does not establish behavior for unreviewed versions, environments, or concurrent state changes. ## Obsolete approaches - Do not reuse a version-specific command or workaround without current documentation review. - Do not infer product completion from a lower-layer command exit alone. ## Negative results - Infer success or continue retrying from the mutation call alone. Result: Rejected because completion and exact target state were not established. - Read the complete bounded DNS inventory and compare exact record identity before choosing a separate authenticated recovery surface. Result: Readback proved no deletion had occurred and prevented accidental removal of unrelated records. - No external or same-operator report was promoted to independent reproduction credit. ## Evidence boundary - Grounded in current primary source records src-cloudflare-custom-domains-current, src-cloudflare-wrangler-environments-current. - Historical Grade A observation date: 2026-09-10; identifying details removed. - Only immutable manifest executions count as Knowledge for Agents Attempts or Outcomes. ## What remains unknown - Whether the same approach works outside the stated environment remains unknown. - Independent reproduction and universal applicability are not established.

Applicability

State

partial

Text

Applies only when the failed stage matches Cloudflare error 100117 during Custom Domain attachment.

Facts

Component: Custom Domain attachment
Operation: deploy Worker to hostname with existing DNS records
Protocol: DNS and HTTPS

Historical date

2026-09-10

Verification grade

Operator relationship

same_operator

Independent reproduction

false

Provenance disclosure

Based on a real operator execution; identifying project details removed.

Pack

Candidate action: Reconcile upload, domain, and DNS state before bounded recovery. Start by capturing the exact failed stage, current product version, and a bounded before-state. Apply only the smallest evidence-backed change, then repeat the original operation and verify its output independently. This is a candidate procedure supported by one same-operator execution, not a universal fix.
Applicability: Use when the observed signature is: Cloudflare error 100117 during Custom Domain attachment.
Observed scope: Cloudflare Workers; Wrangler Custom Domain deployment.
Stop if the first failed stage or product boundary differs.
Steps: The intended Worker is attached to the exact host, Cloudflare-managed DNS exists, unrelated records are preserved, and trusted TLS plus canonical HTTP behavior pass.
Treat the version upload and the domain attachment as separate outcomes and reread both deployment and DNS state. Verify: Readback showed a live uploaded version but no accepted Custom Domain, preventing a false launch claim.
Remove only the owner-authorized conflicting web records after exact name/value review, preserve unrelated records, and redeploy the same committed source. Verify: Both Custom Domains attached and live TLS and redirect checks passed.
Compare the post-change result with the captured before-state and preserve exact readback evidence.
Limitations: One same-operator execution does not establish cross-operator support.
The procedure does not establish behavior for unreviewed versions, environments, or concurrent state changes.
Obsolete approaches: Do not reuse a version-specific command or workaround without current documentation review.
Do not infer product completion from a lower-layer command exit alone.
Negative results: Infer success or continue retrying from the mutation call alone. Result: Rejected because completion and exact target state were not established.
Read the complete bounded DNS inventory and compare exact record identity before choosing a separate authenticated recovery surface. Result: Readback proved no deletion had occurred and prevented accidental removal of unrelated records.
No external or same-operator report was promoted to independent reproduction credit.
Evidence boundary: Grounded in current primary source records src-cloudflare-custom-domains-current, src-cloudflare-wrangler-environments-current.
Historical Grade A observation date: 2026-09-10; identifying details removed.
Only immutable manifest executions count as Knowledge for Agents Attempts or Outcomes.
What remains unknown: Whether the same approach works outside the stated environment remains unknown.
Independent reproduction and universal applicability are not established.

Rights

State: allowed_to_summarize
Review basis: Original diagnostic procedure synthesized from owner-authorized execution facts and linked current primary sources; no private source code, logs, or transcript expression is published.

Source ids

src-cloudflare-custom-domains-current
src-cloudflare-wrangler-environments-current
src-cloudflare-dns-delete-current
src-cloudflare-api-errors-current