sync-api

name	sync-api
description	Reconcile the SDK against the Mollie API spec — checks and optionally fixes types, JSDoc, enums, deprecations, endpoint coverage, and helper wiring. Use when verifying or syncing the SDK with the official API for a single endpoint, a resource, or the whole SDK.

Sync Types with Mollie API

Compare the SDK's TypeScript types against Mollie's master OpenAPI spec and optionally apply fixes. A bundled toolchain does the deterministic work (fetch, resolve, flatten, diff); you apply the judgment (Pick-vs-inline, nullability, breaking changes, deprecation, JSDoc). Spend your tokens on judgment, not on parsing JSON.

Usage

/sync-api <target> [--only structure,docs,wiring]

<target> is a single token — one of:

• operationId (e.g. get-payment, create-refund) — one endpoint
• resource (e.g. refunds, payments) — every endpoint of that resource
• all — every resource (parallel agents, one per resource)

--only scopes which phases run (default: all three). "just sync the docs" → --only docs. If the target doesn't match a known operationId (via extract-spec.mjs --index) or resource directory, ask rather than guessing.

Source of truth

The master spec mollie/openapi:specs.yaml (operationId is the endpoint key, complete, all $refs local). The toolchain fetches and caches it (ETag-validated) under .tmp/sync-api/.

Do NOT hand-fetch doc pages to read schemas. Doc-site slugs are inconsistent with operationIds (e.g. spec list-chargebacks = doc list-payment-chargebacks; create-payment-refund.md 404s — it's create-refund) and a wrong slug returns a 200-status 404 page that parses as an empty "in sync" result. Doc pages are only used for @see URLs, always HTTP-200-verified before writing (see references/apply.md).

Toolchain (scripts/, run via Bash)

Run from the repo root (paths below are repo-root-relative; the scripts resolve the repo root themselves, so the working directory only matters for locating the script file).

Command	Output
node .claude/skills/sync-api/scripts/extract-spec.mjs --index	every operation: METHOD path -> operationId
node .claude/skills/sync-api/scripts/extract-spec.mjs <operationId> [--side response|request|params] [--show|--json]	bare: summary + self-check status. --show: rendered digest. --json: digest rows. Default side: response (GET) / request (POST/PATCH/PUT).
node .claude/skills/sync-api/scripts/extract-spec.mjs <operationId> --meta [--json]	the operation's own summary / description / deprecated — the anchor for the binder-method JSDoc check (Phase 2)
node .claude/skills/sync-api/scripts/extract-sdk.mjs <file.ts> [--json]	SDK structural map: Pick/PickOptional/inline/heritage, JSDoc, @see, duplicate fields; for a binder, also .methods[] (method name + JSDoc + @see)
node .claude/skills/sync-api/scripts/diff.mjs <operationId> <file.ts> <TypeName>	deterministic field delta: missing / extra / type+doc drift. Side is chosen from the SDK type (see below); readOnly/writeOnly filtered accordingly; bases resolved (incl. cross-file). Field-level only — method JSDoc is Phase 2.

The digest preserves every description verbatim — that prose (deprecations, constraints, access restrictions, method-specific relevance) is the core value and the scripts never summarize it. If extract-spec.mjs exits non-zero on a digest, a description was dropped — treat as a bug, do not proceed on partial data. (A missing side — e.g. a 204 No Content response, or a GET with no query params — is a clean exit 0 with empty output, not an error.) The spec is fetched once and cached; a recent cache is reused without a network call. Offline → it warns once and uses the cache; pass --refresh to force a re-fetch.

Step 1 — Analyze

For each operation in scope:

1. Discover the SDK side. Glob the resource's files (src/data/**/<resource>/*.ts, src/binders/**/<resource>/*.ts); run extract-sdk.mjs <data.ts> --json and extract-sdk.mjs <parameters.ts> --json to see the exported types.

2. Run diff.mjs for each operation against its SDK mirror(s). An operation has up to two mirrors, and diff.mjs picks the comparison side automatically from the SDK type you pass:

   • Response ↔ the resource's Data interface — diff <op> <data.ts> <ResourceData> (every GET/POST/PATCH that returns a body).
   • Request body + query params ↔ the operation's *Parameters type — diff <op> <parameters.ts> <OpParameters> (Create*/Update* for body; Get*/Page*/Iterate* for query params; Cancel*/Delete* for testmode-only bodies).

   Run both where both exist. The diff is the mechanical delta; spend judgment on it, not on re-deriving it.

3. Apply judgment over the delta + the verbatim descriptions, across three phases in order (each depends on the previous being resolved):

Phase 1 — Structure

Resolve the diff "MISSING" / "IN SDK not in spec" / type findings:

• Missing fields — add with ? optional by default, always with JSDoc (the spec description, verbatim) and an @see link.
• Where a request field lives — Pick vs inline (the hardest call): a field belongs inline in parameters.ts ONLY if (a) it exists on no Data interface anywhere in src/data/ (request-only / writeOnly, e.g. cardToken, dueDate), OR (b) the spec genuinely differs between request and response for that field (different description, constraints, or type — compare both). Otherwise use Pick/PickOptional from the owning Data interface. extract-sdk.mjs flags fields defined via Pick and inline (⚠️ DUPLICATES) — those must be deduplicated to Pick/PickOptional (verify the Data interface's JSDoc is complete first, since it becomes canonical).
• Always Pick, never Omit — Omit silently leaks newly-added source fields.
• "IN SDK, not in spec" — never auto-remove; judge over-declaration vs spec-incompleteness. Param-absence is a proxy, not proof. When the spec's operation description explains the absence, diff.mjs appends it as — spec note: "…" — that prose is authoritative (e.g. testmode on the terminals pairing endpoints: "does not support test mode yet" → a real over-declaration; mind the "yet" — the answer may be "keep, support is imminent"). With no spec note (e.g. testmode on the live-only settlement endpoints), it's a softer call — genuinely unsupported, or just unlisted by Mollie? Flag under "Needs attention" either way.
• _links / _embedded entries are structure too — diff.mjs flags a missing link/embed property as [P1] _links.<name>: in spec, not on <Links interface>. Add the property (e.g. to the *Links interface) with JSDoc, exactly like any other field. (The helper for it is a separate concern — Phase 3.)

Nullable vs optional (see CLAUDE.md for the project convention):

• On request fields, spec type: [..,'null'] does NOT mean T | null. Sending null to clear a field is a distinct semantic most Mollie fields don't support — default to T unless the description explicitly says null clears the value.
• Never downgrade an existing Nullable<T> (confirmed behavior). Don't auto-flip optionality from the spec — the docs are unreliable here.

⚠️ BREAKING CHANGES — warn loudly, never auto-apply. Removing/renaming a field/type/enum/method; optional→required on a request param; required→optional on a response field (breaks consumers doing obj.field.prop, even if the spec says optional — the SDK may keep it required based on observed behavior); type changes. Prefix with ⚠️ BREAKING: under "Needs attention", explain why, and prefer non-breaking alternatives (add alongside, @deprecated the old, union types). Response optionality changes require explicit user confirmation.

Phase 2 — Documentation

On the final field locations (after Phase 1):

• Deprecation — check the digest's deprecated flag, xDeprecatedEnum, AND the description prose ("will be ignored", "no longer supported", "use X instead"). Any deprecation → @deprecated JSDoc tag on the SDK field/method.
• JSDoc drift / content loss — diff.mjs flags no-JSDoc and JSDoc may drop N spec sentence(s) (the SDK JSDoc lost content the spec has). This is coverage, not verbatim — the goal is that the spec's information is reflected in the code, not copied word-for-word. Apply judgment:
  • Intentional drift is fine — SDK-specific notes, or corrections where the docs are wrong (e.g. docs say a field is required but it isn't). Keep these; a flag here just means "confirm it's deliberate".
  • Accidental truncation is not — a dropped sentence with no reason (constraints, possible values, method-specific relevance) should be restored from the spec description.
  • Ignore the shared Amount/URL boilerplate ("In v2 endpoints, monetary amounts/URLs are represented as objects…") — it lives on the shared Amount/Url type, not repeated per field; its absence is not a gap.
• @see format — diff.mjs flags old-@see-format (/reference/v2/<api>/... → /reference/...). For bulk, state the count.
• Binder method JSDoc — diff.mjs does NOT cover this (it's method-level, not field-level), so it must be done explicitly. Run extract-spec.mjs <op> --meta (the operation's summary/description/deprecated) and extract-sdk.mjs <binder> --json (.methods[] with JSDoc + @see); map each method to its operation via its @see slug. Then flag:
  • @deprecated mismatch (mechanical) — operation deprecated: true but the method JSDoc lacks @deprecated, or vice versa.
  • Factual drift (judgment) — product claims, supported-method lists, or legacy-flow references in the method JSDoc that the operation contradicts or no longer mentions (e.g. "supports Cards and Klarna", an Orders-shipment flow). Ignore mere wording differences.

Phase 3 — Wiring (helper coverage)

An invariant over the current state: every _links / _embedded entry the SDK declares should have a corresponding helper — regardless of whether the entry was just added (Phase 1) or has been there all along. (Existence + correctness of the entry itself is Phase 1/2; this phase only asks "is there a helper for it?")

diff.mjs flags [P3] _links.<name>: no helper (expected get/has<Name>[Url]) — Helper class: <file | NONE — must be created>. For each, add the helper using the right pattern (list→HelpfulIterator + hasX; single resource→getX; URL-only→getXUrl), creating the resource's *Helper.ts if none exists. See references/wiring.md for the patterns and the 4-file _embedded procedure. Base self/documentation are never helper-exposed and aren't flagged.

4. Report — issues only, grouped by phase; omit empty phases; counts for bulk items; field path + what differs + file:line for individual ones. Never auto-remove SDK fields absent from the spec — flag under "Needs attention". Then a Summary: Doc-synced (no type change), Added, Needs attention (omit empty categories).

Step 2 — Apply

1. Ask which phases/categories to apply. If the user selects nothing to change, stop here — there are no edits to make, so the working tree is never touched.
2. Only if changes will be made, check the working tree is clean (do this after the selection, before the first edit). Run git status --porcelain --untracked-files=no (the gitignored .tmp/ cache and untracked files are correctly excluded). If it shows uncommitted changes to tracked files, STOP and ask the user — sync edits would interleave with their existing work, muddying the diff. Lead with the safer option (the tree is already dirty, which is the only reason this prompt appears): (a) isolate in a fresh worktree (recommended/default) — git worktree add ../mollie-api-node-sync-<target> -b sync/<target> (clean checkout of the current commit; their WIP stays put); or (b) apply here anyway (sync edits interleave with the existing changes). Do not proceed until they choose.
3. Read references/apply.md (Pick/PickOptional mechanics + the mandatory pre-check, @see format + verify-before-write, intersection/empty-interface style) and apply edits in phase order.

Post-apply gate (MANDATORY): after edits, run yarn build:declarations (typechecks the whole graph via src/types.ts, ~2s) and npx eslint --ext .ts src/<touched dirs>, then npx prettier --write <touched files only> (NOT yarn lint — it reformats the whole tree). Fix any diagnostics before reporting done. The gate proves edits are type-valid; it does not validate optionality/breaking-change judgment — those stay under "Needs attention".

Post-apply description-coverage review: re-run diff.mjs on each edited (op, type) pair and look at the JSDoc may drop … flags. This catches the common failure where the apply step shortened a description while writing JSDoc — especially on newly-added fields, where a coverage gap is almost certainly accidental truncation (you just added it from the spec — restore the dropped content). For pre-existing fields, judge intentional drift vs accidental per the Phase 2 rules. This is a review, not a hard gate — fix accidental loss, keep deliberate deviations.

Parallelization

For a resource or all, fan out one agent per resource (never per endpoint — the request-vs-response Pick decision needs both specs in one context; never per check — the phases are dependency-ordered). Each agent runs the full analyze step for its resource and writes verbatim findings to .tmp/sync-api/report-<resource>.json (apply reads these, immune to context summarization). Use the contract in references/agent-prompt.md. --only scopes each agent's phases.