Breaking down: "A Node backend loses the response to a Stripe POST. Use https://docs.stripe.com/api/idempotent_requests to write a small retry decision table for a lost response, a received HTTP 500, changed parameters, and a key older than 24 hours. State when to retain the original key and what the API stores. Separate facts from our proposed application policy. Do not imply that a timeout proves no charge occurred."

Identified 8 research target(s) to investigate; these are not established facts

Deep mode: up to 4 paid/cached/public reads plus one bounded gap-expansion pass when needed.

Web search: 4/4 planned queries attempted, 3 succeeded, 24 public page previews, 1 unavailable queries. Snippets are discovery only. Public reads spend no USDC; model and service operating costs remain separate.

Discovered 0 verified creator source(s) and 24 free public reference(s)

Claim-aware portfolio (exhaustive; bounded selection, not a claim of global optimality) selected 4/16 positive proposal(s): 4 free/cache selections + 0 paid fresh selections, predicting 8/8 claim(s) above the evidence floor with $0.000000/$0.015000 fetch USDC reserved.

Free-preview pre-check maps an actionable source to every sub-claim (8/8); paid reading may proceed within the budget.

READ Instagram - selected original public page, 0 USDC; not a cache hit.

Public page unavailable (html-extraction-unavailable); no evidence admitted. Continuing research.

READ How to Retry API Requests Safely - Vincent Schmalbach - selected original public page, 0 USDC; not a cache hit.

Read extracted public text from https://www.vincentschmalbach.com/how-to-retry-api-requests-safely/ - S1; quote matching establishes source grounding, not fact verification.

READ Idempotency - Alguna Docs - selected original public page, 0 USDC; not a cache hit.

Read extracted public text from https://alguna.com/docs/api-reference/v2/idempotency - S2; quote matching establishes source grounding, not fact verification.

READ Stripe API Reference - selected original public page, 0 USDC; not a cache hit.

Read extracted public text from https://docs.stripe.com/api/idempotent_requests?javascript=false&lang=node - S3; quote matching establishes source grounding, not fact verification.

Sub-claim "According to https://docs.stripe.com/api/idempotent_requests…": 90% covered by S3 — S3 (Stripe docs) states Stripe saves the resulting status code and body of the first request for any given idempotency key, regardless of success or failure, and that keys can be removed automatically after they are at least 24 hours old. Minor gap: the exact retention guarantee wording ('at least 24 hours') is implied rather than stated verbatim.

Sub-claim "According to https://docs.stripe.com/api/idempotent_requests…": 40% covered by S3 — S3 supports that subsequent requests with the same key return the same result, which implies retrying with the same key is safe, but the Stripe page excerpt does not explicitly give a lost-response/timeout retry recommendation. S1 (non-Stripe) says do not generate a new key after a timeout, but that is not the requested Stripe source.

Sub-claim "According to https://docs.stripe.com/api/idempotent_requests…": 60% covered by S3 — S3 states subsequent requests with the same key return the same result, including 500 errors, which directly supports retrying with the same key. However, the excerpt does not explicitly phrase this as a retry recommendation.

Sub-claim "According to https://docs.stripe.com/api/idempotent_requests…": 80% covered by S3 — S3 states the idempotency layer compares incoming parameters to those of the original request and errors if they are not the same to prevent accidental misuse. This directly answers that changed parameters cause an error rather than replay, though the excerpt does not spell out the exact retry action.

Sub-claim "According to https://docs.stripe.com/api/idempotent_requests…": 70% covered by S3 — S3 states keys can be removed automatically after they are at least 24 hours old and that a new request is generated if a key is reused after the original is pruned. This answers the behavior, but the excerpt does not explicitly frame it as a retry decision.

Sub-claim "According to https://docs.stripe.com/api/idempotent_requests…": 60% covered by S3 — S3 supports retaining the same key for subsequent retries of the same request and replacing it only after pruning or for a new request, but the excerpt does not give a consolidated retain-versus-replace rule.

Sub-claim "What does https://docs.stripe.com/api/idempotent_requests sa…": 10% covered by S3 — S3 does not address whether a timeout or lost response proves no charge occurred. S1 (non-Stripe) discusses the ambiguity of timeouts, but the requested Stripe page excerpt does not answer this.

Sub-claim "What proposed application policy should we adopt for each of…": 40% covered by S1, S3 — S1 provides general retry-safety guidance (reuse the same key, do not generate a new key after a timeout), and S3 provides Stripe facts that can inform policy, but no source states a proposed application policy for all four cases separately from the documented facts.

Coverage is adequate for the core Stripe facts from S3. The main gaps are the lost-response retry recommendation and the timeout-proves-no-charge point, but the remaining budget is only 0.015, so no skipped source is affordable. The skipped sources are also mostly non-Stripe or tangential, so buying more is not warranted.

Final check — "According to https://docs.stripe.com/api/idempotent_requests…": 100% assessed by S3

Final check — "According to https://docs.stripe.com/api/idempotent_requests…": 40% assessed by S3

Final check — "According to https://docs.stripe.com/api/idempotent_requests…": 90% assessed by S3

Final check — "According to https://docs.stripe.com/api/idempotent_requests…": 100% assessed by S3

Final check — "According to https://docs.stripe.com/api/idempotent_requests…": 100% assessed by S3

Final check — "According to https://docs.stripe.com/api/idempotent_requests…": 80% assessed by S3

Final check — "What does https://docs.stripe.com/api/idempotent_requests sa…": 10% assessed by S3

Final check — "What proposed application policy should we adopt for each of…": 0% assessed

Final coverage assessment — The supplied Stripe documentation excerpt (S3) directly answers most of the factual sub-claims: it states that Stripe saves the status code and body of the first request for a key regardless of success/failure, that keys can be pruned after at least 24 hours and a reused pruned key generates a new request, that the idempotency layer compares parameters and errors if they differ, and that subsequent requests with the same key return the same result including 500 errors. It also implies retaining the original key for retries of the same request and replacing it for a new logical operation, though it does not phrase this as an explicit retention rule. It does not explicitly state a retry decision for a lost response/timeout, nor does it explicitly say a timeout does not prove no charge occurred. The proposed application policy is not documented by Stripe and must be supplied by the user; S1 provides general retry-safety context but is not the requested Stripe source. The assessment does not establish a complete supported answer for every requested part.

Synthesizing a grounded answer from 3 source(s)…

Relevance review returned; only checked excerpts can retain support, and review cannot raise it.

Delivering qualified source excerpts; complete synthesis and per-assertion support remain unverified.

Source-matched public excerpt (no creator reward) — S3, research target 1, proposed support 90% (estimate, not entailment): “Stripe’s idempotency works by saving the resulting status code and body of the first request made for any given idempotency key, regardless …”

Source-matched public excerpt (no creator reward) — S3, research target 1, proposed support 80% (estimate, not entailment): “You can remove keys from the system automatically after they’re at least 24 hours old.”

Below support/reward gate — S3, research target 2, proposed support 20% (estimate, not entailment): “Subsequent requests with the same key return the same result, including 500 errors.”

Below support/reward gate — S3, research target 3, proposed support 20% (estimate, not entailment): “Subsequent requests with the same key return the same result, including 500 errors.”

Source-matched public excerpt (no creator reward) — S3, research target 4, proposed support 50% (estimate, not entailment): “The idempotency layer compares incoming parameters to those of the original request and errors if they’re not the same to prevent accidental…”

Source-matched public excerpt (no creator reward) — S3, research target 5, proposed support 50% (estimate, not entailment): “We generate a new request if a key is reused after the original is pruned.”

Below support/reward gate — S3, research target 6, proposed support 30% (estimate, not entailment): “A client generates an idempotency key, which is a unique key that the server uses to recognize subsequent retries of the same request.”

Source-matched public excerpt (no creator reward) — S1, research target 7, proposed support 90% (estimate, not entailment): “The server may never have received the request, or it may have finished the work and lost the response on the way back.”

Below support/reward gate — S1, research target 8, proposed support 30% (estimate, not entailment): “Generate the key before the first request and reuse it for every retry.”

Below support/reward gate — S1, research target 8, proposed support 30% (estimate, not entailment): “Do not generate a new key after a timeout.”

Prepared source excerpts citing 2 source(s); complete synthesis is unverified

Confidence: Low — Only source excerpts are delivered; complete synthesis and per-assertion support remain unverified. Evidence assessment: 5 sub-claims remain below the evidence threshold.

vincentschmalbach.com contributed 30% - free public reference; reward share withheld

stripe.com contributed 70% - free public reference; reward share withheld

Done. Spent $0 across 0 confirmed/simulated payment(s) to creators.