Preflightpay-per-audit continuity checking · by canonkeeper

Let your AI assistant buy the audits

Everything on this site is also an MCP server, so an assistant such as Claude can quote an audit, pay for it and read the findings back to you. It works inside limits you set with PayPal: it never holds a PayPal login or key, and only you can approve a payment.

A real session: Claude (Claude Code, headless) connected to Preflight over MCP opens a $20 budget capped at $6 a purchase; the person approves it on PayPal; Claude audits the demo series, asks the person to confirm a finding they say is wrong, checks a draft and closes the budget, $13.44 refunded through PayPal. PayPal sandbox, on a local copy of Preflight answering the demo series with real Gemini answers recorded for the demo series (gemini-3.5-flash-lite reading, gemini-3.6-flash judging), replayed offline; sped up. The transcript.

Read the whole session: what the person asked, every tool Claude called, every reply

Open a $20 Preflight budget for checking my drafts, at most $6 a purchase.

→ open_budget(amount_usd=20, max_per_purchase_usd=6)

← amount: 20.00 USD · approve_url: (a PayPal link for the person)

Your $20 budget is set up, with a $6 cap per purchase. It isn't funded until you approve it. 1. Open this link and approve the PayPal payment: https://www.sandbox.paypal.com/checkoutnow?token=53J38858875010816 2. Tell me once you've approved, and I'll confirm the budget. You can see every spend and close the budget at http://127.0.0.1:8791/budget/VOqtzofzSOLxr-GK.

You approve the $20 on PayPal (sandbox, test money).

I've approved it on PayPal. Audit the Saltmarsh demo series and pay from the budget.

→ confirm_budget(budget_id="VOqtzofzSOLxr-GK")

→ quote_demo_series()

← status: active

← price: 5.05

Price $5.05 is under the $6 cap and within the balance. Paying.

→ pay_with_budget(job_id="nzkckRojZ8g", budget_key="pfk_…")

← paid: True · budget_left: 14.95 · amount: 5.05 USD

→ audit_status(job_id="nzkckRojZ8g")

← status: done · contradictions: 5

→ get_findings(job_id="nzkckRojZ8g")

← 5 findings

The Saltmarsh audit found 5 contradictions. I paid $5.05 from the budget, so $14.95 is left. Every suggested fix targets the later book, The Return. 1. Tobias Crane's wound (high): shot in the shoulder in The Harbour, in the leg in The Return. 2. Hester Vale's birthplace (high): Saltmarsh in The Harbour, Dunmere in The Return. 3. Oswin Reed (high): he dies in The Wreck, then "walked to Saltmarsh" in The Return. 4. Ivy Marlowe's eyes (medium): green in The Harbour, blue in The Return. 5. Ivy Marlowe's hair (medium): red in The Harbour, grey in The Return. The audit's explanations cite different chapter numbers than the quotes show (for example, Chapter II instead of Chapter I). Check the report before you act on the chapter references. Full report: http://127.0.0.1:8791/jobs/nzkckRojZ8g/report

The Oswin Reed one is wrong: he only faked his death in The Wreck. Mark it.

→ mark_finding_wrong(job_id="nzkckRojZ8g", finding_index=2, note="Oswin Reed only faked his death in The Wreck, so appearing in The Return is not a contradiction.")

← a link for the person to confirm it: nothing marked, no money moved yet

It isn't marked yet. You need to confirm it yourself: open this link and press "Mark it wrong": http://127.0.0.1:8791/jobs/nzkckRojZ8g?mark=2&note=Oswin+Reed+only+faked+his+death+in+The+Wreck%2C+so+appearing+in+The+Return+is+not+a+contradiction.#mark-2 Once you confirm, the note goes on the report and $0.50 comes back to you.

You confirm it on your job page: $0.50 back to the budget.

Now check the demo series' next draft against it, from the budget, and tell me what you found.

→ get_demo_draft()

← ok

→ check_draft(job_id="nzkckRojZ8g", name="draft-04-the-ledger.txt")

← price: 2.01

$2.01 is under the $6 cap and within the $14.95 left. Paying.

→ pay_with_budget(job_id="gXUfp9ca9hM", budget_key="pfk_…")

← paid: True · budget_left: 13.44 · amount: 2.01 USD

→ audit_status(job_id="gXUfp9ca9hM")

← status: done · contradictions: 2

→ get_findings(job_id="gXUfp9ca9hM")

← 2 findings

The draft check found 2 contradictions. It cost $2.01 and the budget now shows $13.44. That is $0.50 more than I expected, which suggests your Oswin refund went through. 1. Tobias Crane's birthplace (high): The Harbour says Kelby, and the draft says Portmouth. The fix is to change the draft line to "born in Kelby." 2. Ivy Marlowe's eyes (medium): the draft says brown. The series already conflicts: green in The Harbour, blue in The Return. The fix is to change the draft to green. The Return's blue is the existing error from the first audit. Two things in the draft passed: - Hester Vale's brown eyes: the draft explains them with tinted glasses. - Ivy walking to Kelby and Saltmarsh: this wasn't flagged. Full report: http://127.0.0.1:8791/jobs/gXUfp9ca9hM/report

Thanks. Close the budget.

→ close_budget(budget_id="VOqtzofzSOLxr-GK")

← Error executing tool close_budget: 1 validation error for close_budgetArguments budget_key Field required [t

→ close_budget(budget_id="VOqtzofzSOLxr-GK", budget_key="pfk_…")

← status: closed · refunded to PayPal: 13.44

The budget is closed, and the unused $13.44 has been refunded to your PayPal. The refund shows as completed. - Spent: $7.06 in total. That was $5.05 for the audit and $2.01 for the draft check. - Credit: $0.50 came back for the Oswin Reed finding you marked wrong.

Recorded 2026-10-27 21:40 with scripts/video/agent_session.py: PayPal sandbox, on a local copy of Preflight answering the demo series with real Gemini answers recorded for the demo series (gemini-3.5-flash-lite reading, gemini-3.6-flash judging), replayed offline. The spending key is masked.

1. Connect it

Preflight's MCP address (streamable HTTP, no sign-in)

Claude (web or desktop): add a custom connector and paste the address above.
Claude Code: claude mcp add --transport http preflight https://preflight-kq1o.onrender.com/mcp
Any other MCP client that speaks streamable HTTP: the same address.

2. Ask for what you want

“Open a $20 Preflight budget, at most $6 a purchase, for 30 days.” It replies with a PayPal link. You approve it; the assistant cannot. The limits are optional, and you can tighten them later on the budget page.
“Audit the Saltmarsh demo series and pay from the budget.” It quotes, pays and waits for the report.
“Check the demo draft against the series.” It reads back each contradiction with both passages.
“Close the budget.” What is left goes back to your PayPal account.

For your own books, ask it for an upload link: you upload the files on this site and see the price before anything is bought. This site runs on a free AI tier that may use submitted text for training, so public-domain books only.

3. What it can and cannot do

The assistant can	It cannot
open a budget or a single-audit order	approve a payment: only you can, on PayPal
pay for audits and draft checks from a budget	spend past the balance, your limit per purchase or your end date
ask you to mark a finding wrong, or to take a failed audit's refund (you confirm either on your job page)	hold your PayPal login, a key or a card, or move money back or forth without you
close the budget	send money anywhere but back to your PayPal account

Nothing is sent to a model before PayPal has captured the payment. Every spend, credit and refund is listed on the budget's page, which the PayPal approval takes you to. A failed audit is credited back to the budget; a single order is refunded through PayPal with one button.

Step by step: who does what, and where PayPal comes in

Sequence: the assistant opens a $20 budget at most $6 a purchase; Preflight creates a PayPal order and gives the assistant an approval link for the person and a spending key; the person approves on PayPal (only the person can); Preflight captures $20; the assistant quotes the demo series and pays from the budget, never past the balance or the person's limits; the audit runs, nothing reaching a model before a capture; the assistant reads the findings and asks to mark one wrong; Preflight returns a link only the person can confirm; the person confirms on the job page and $0.50 is credited back to the budget; the assistant closes the budget and Preflight refunds the unused balance through PayPal.

The 19 tools it gets

Each tool tells the assistant what it does to the world (MCP annotations), so an assistant that asks before acting knows which ones spend money or cannot be undone.

request_upload_link Get a link where the person uploads their books (one file per book) and sees the price.
upload_status Whether the person has uploaded the books yet; the job id and price once they have. reads only
open_budget Ask the person to fund a budget (5 to 200 USD) you may spend on audits and draft checks without asking each time. talks to PayPal
confirm_budget After the person approved the budget's payment: capture it and make the budget spendable. talks to PayPal
mark_finding_wrong When the person says a reported contradiction is wrong: returns a link where THEY confirm it; it is then noted on the report and part of the price comes back to them (0.50 each, at most half the price). reads only
rule_on_finding Record the author's ruling on an item the audit left to them ('needs your judgement': get_findings with include_cleared, verdict 'ambiguous').
budget_status A budget's balance and every spend, credit and refund, by the budget_key (pfk_…) open_budget returned. reads only
pay_with_budget Pay a quoted job (an audit or a draft check) from the budget and start it. cannot be undone
close_budget Close the budget: no more spending; the unused balance is refunded to the person's PayPal. cannot be undone talks to PayPal
quote_demo_series Quote an audit of the Saltmarsh Chronicles, an invented three-book demo series with five planted continuity errors and one item for the author to judge, to try the whole flow (pay, findings, draft check) without a series of the person's own.
get_demo_draft The demo series' next book, a draft with planted slips: pass its name and text to check_draft with the finished demo audit's job_id. reads only
quote_series Price an audit from the book texts.
order_audit Create the PayPal order for a quoted job. talks to PayPal
confirm_payment After the person approved on PayPal, capture the payment and start the audit. talks to PayPal
audit_status Current status of a job (quoted/ordered/paid/running/done/failed) and report links when done. reads only
get_findings The audit's findings as data: each contradiction with its quotes, explanation and suggested fix. reads only
check_draft Quote a check of the author's next draft against a finished series audit (job_id): only the places where the draft disagrees with the published books, each with a fix to the draft.
delete_job Delete the job's manuscripts, bible, reports and cached model responses, keeping only a receipt. cannot be undone
refund_failed_audit When an audit failed (status 'failed') and the person wants their money back instead of a free retry: returns a link where THEY confirm the full refund (to their PayPal, or into the budget that paid). reads only

Or use the website yourself