n8n-io

post-build-flow

Handles workflow verification and setup after build-workflow succeeds, or when the message contains workflow-verification-follow-up or workflow-setup-required. Load after direct builds, when verificationReadiness requires action, or on orchestrator verify/setup follow-up turns.

n8n-io 201,193 60,225 Updated 1w ago

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Install

npx skillscat add n8n-io/n8n/post-build-flow

Install via the SkillsCat registry.

SKILL.md

Post-Build Flow

Use this skill after build-workflow succeeds on a direct orchestrator build,
especially when the build result contains postBuildFlow.required: true, or when
the current message contains <workflow-verification-follow-up> or
<workflow-setup-required>.

These instructions are in English, but user-visible text you write while
following them stays in the user's conversation language.

For trigger inputData shapes, read
${N8N_WORKSPACE_DIR}/knowledge-base/reference/trigger-input-data-shapes.md in
the sandbox workspace when available, or load this skill's
references/trigger-input-data-shapes.md linked file.

Verification follow-up

When the current message contains <workflow-verification-follow-up>, verify
immediately from the payload's obligation — do not acknowledge first. If the
obligation is ready_to_verify or verifying, call verify-built-workflow. Do
not call workflows(action="setup") in this turn and do not declare the
workflow finished if outcome.setupRequirement.status === "required" — setup is
routed automatically as a separate <workflow-setup-required> step after
verification.

Setup follow-up

When the current message contains <workflow-setup-required>, your first action
is to call workflows(action="setup") with the workflowId from the payload. Do
not verify, do not ask, do not write a message first — the inline setup card in
the AI Assistant panel is the user-visible surface. If it returns deferred: true, respect the user's choice and do not retry with any other setup tool.
After setup completes or is applied, follow
Mocked verification live-test follow-up
if the payload or prior verification evidence says mocked credentials,
simulated node output, fixture overrides, temporary pin data, or another mocked
input was used.

Choosing the credential type for a service

Pick in this order:

  1. A dedicated credential type (slackApi, notionApi, …) whenever one
    exists — search with credentials(action="search-types").
  2. Simplified Custom Auth (httpTemplatedCustomAuth) for any service
    without a dedicated type whose auth is expressible as header/query/body
    values — which covers API keys and bearer tokens (Authorization: Bearer <token> becomes {"headers":{"Authorization":"Bearer {{api_key}}"}}, not
    httpBearerAuth). Always provide a recipe (below) so the user only pastes
    their secret.
  3. Plain generic types (httpBasicAuth, httpDigestAuth, oAuth2Api, …)
    only for what a template cannot express: basic auth's base64-encoded pair,
    digest's challenge-response, OAuth flows — or when the user explicitly asks
    for a specific plain type: an explicit user choice wins (setup accepts it
    with allowPlainGenericAuth: true).

Credential recipes for Simplified Custom Auth

When the workflow authenticates a service through Simplified Custom Auth,
include credentialHints in the same workflows(action="setup") call so the
setup card pre-fills the credential and the user only pastes their secret —
instead of facing an empty JSON template they'd have to decode from the
provider's docs. Before composing the hints, load the
credential-recipe-research skill and execute its lookup procedure — the
template, docsUrl and testUrl must come from the provider documentation
it has you fetch, never from memory:

  • template — the auth request parts (headers/qs/body) exactly as documented,
    with {{placeholder}} markers where the user's values go.
  • placeholders — one entry per marker: name, user-facing title, an
    optional info clarifying the value itself — its format or which of the
    provider's tokens it is (e.g. "Starts with tvly-"). Never where to obtain
    it, and never a URL or domain: the user asks the AI Assistant for that from
    the credential form. type is password unless clearly non-secret (at
    least one placeholder must stay password). Add optional: true only when
    the provider documents the value as optional (e.g. an org/region
    qualifier) — template entries referencing an empty optional placeholder are
    omitted from the request.
  • docsUrl — the provider page where a logged-in user CREATES/COPIES the
    secret (e.g. https://replicate.com/account/api-tokens) — never the API
    reference. Not shown in the form: the AI Assistant help thread uses it to
    send the user to the exact page. Found via the credential-recipe-research
    procedure; omit when it finds nothing conclusive.
  • testUrl — a documented side-effect-free GET that rejects a bad key with
    401/403, used to verify the credential on save and later retests; never one
    of the workflow's own endpoints, never anything billable. Found via the
    credential-recipe-research procedure; omit when nothing qualifies — a
    credential without a testUrl saves fine and honestly shows "could not be
    verified", which beats a false green.
  • acceptedStatusCodes — almost always omit; the user can adjust it later on
    the credential if a service's auth answers 401/403 to valid GETs.
  • suggestedName — display name for the created credential.

Example — fal.ai's docs say requests use Authorization: Key <FAL_KEY> and
GET https://api.fal.ai/v1/models/usage is a documented side-effect-free
endpoint that rejects a bad key (the model-serving host fal.run is not a
key-check endpoint):

{
  "action": "setup",
  "workflowId": "...",
  "credentialHints": [
    {
      "suggestedName": "fal.ai API Key",
      "template": {
        "headers": { "Authorization": "Key {{api_key}}" }
      },
      "placeholders": [
        {
          "name": "api_key",
          "title": "fal.ai API key",
          "info": "Key ID and secret, separated by a colon",
          "type": "password"
        }
      ],
      "docsUrl": "https://fal.ai/dashboard/keys",
      "testUrl": "https://api.fal.ai/v1/models/usage"
    }
  ]
}

Never put a real secret in a recipe — the user pastes it in the setup card and
it is stored redacted in the credential. Add nodeName when several nodes use
Simplified Custom Auth for different services. You cannot see the secret, but
once setup reports the credential applied, treat it as fully configured — the
{{placeholder}} markers live only in the template; the stored values replace
them at request time. If a live test later fails with an auth error, that is
the moment to have the user re-open the credential and re-paste the value.

If the user defers setup instead, don't hand them manual field-by-field
credential instructions for the n8n editor — tell them to reopen setup when
they're ready: the card pre-fills everything except their key.

Publishing and testing

Publishing is never required for testing. Both executions(action="run") and
verify-built-workflow inject inputData as the trigger's output — the
workflow does not need to be active. Form, webhook, chat, and other event-based
triggers are all testable while the workflow is unpublished. Never publish a
workflow as a precondition for running it.

For workflows produced by build-workflow, always verify with
verify-built-workflow, never with raw executions(action="run").
It reuses
the build outcome simulation plan, mocked credentials, and temporary pin data, so
destructive nodes are pinned and it is safe to call repeatedly. A raw
executions(action="run") runs the workflow live with no pin data, and on a
workflow you just verified it surfaces a redundant run-approval prompt to the
user right after verification already executed the workflow. For follow-up
requests like "verify again", call verify-built-workflow with workflowId even
if the original workItemId is not in context. For alternate deterministic
scenarios, pass fixtureOverrides keyed by simulated node name instead of trying
to force data through the trigger.

Reserve executions(action="run") for runs the user explicitly asked for
(e.g. "run it now", "execute it against my real data"). Never call it on your own
to re-test, expand coverage, or "prove the full chain" of a workflow you just
built or verified: re-run verify-built-workflow (with fixtureOverrides to
reach an unverified branch) instead, or report the partial coverage and let the
user decide whether to run it.
If fixtureOverrides is rejected with invalid_fixture_override, the target
node was not classified as simulated in the build outcome. Do not retry the same
override. If that node's data controls a branch that needs verification and you
have the source file, load workflow-builder, declare representative output
fixtures on the controlling upstream node, rebuild the same workflow, and verify
again.

After build-workflow succeeds

  1. Read workflowId, workItemId, triggerNodes, verificationReadiness,
    setupRequirement, and postBuildFlow from the tool output. If the output
    is missing a workflowId, explain that the build did not submit.
    • Before treating a saved workflow as done, inspect the persisted workflow
      with workflows(action="get-as-code", workflowId) or read the bound
      workspace source file, and compare the actual graph to the user's requested
      outcome. Build/save success only means a workflow was saved; it does not
      prove the saved workflow is good.
    • If the persisted workflow is missing the requested outcome, has an obvious
      dead-end draft shape, or the verification evidence is weak, load the
      workflow-builder skill and patch the same workflow with build-workflow
      using the existing workflowId and workItemId; then inspect and verify
      again.
    • If verificationReadiness.status === "already_verified", treat the
      workflow as verified and do not call verify-built-workflow again.
  • If verificationReadiness.status === "ready", call
    verify-built-workflow with the workflowId, the workItemId when you
    have it, and the trigger-appropriate inputData shape.
  • If verificationReadiness.status === "needs_setup", call
    workflows(action="setup") with the workflowId so the user can configure it
    through the inline setup card in the AI Assistant panel.
  • If verificationReadiness.status === "not_verifiable", do not infer
    lower-level verification conditions; use the readiness guidance to give a
    clear warning or manual-test note. This is a warning completion state, not
    a verified state and not an infinite blocker.
  1. Judge coverage, not just status. A verify-built-workflow result with
    success: true but a non-empty nodesNotReached is partial evidence:
    the execution ended early (see lastNodeExecuted and coverageNote) and
    the listed nodes — including any planned simulations — never ran.
    • Most common cause: a lookup/query node returned zero items (n8n stops
      downstream nodes on empty item lists). If the dead-end is a Data Table
      lookup, insert a matching test row with data-tables(action="insert-rows"),
      re-run verify-built-workflow, and delete the test row afterwards.
    • If you cannot seed the data source, report honestly: name which nodes
      were verified and which were not, and tell the user the unreached part
      needs a manual test. Do not start a live executions(action="run")
      yourself to reach those nodes; offer the user a test instead. Never claim
      end-to-end verification when nodesNotReached is non-empty.
    • If the unreached nodes sit behind IF/Switch logic controlled by a live or
      nondeterministic upstream node, and alternate-branch verification is part
      of this turn's goal, first try one source-file repair: add representative
      output fixtures to that upstream node, rebuild the same workflow, and
      re-run verify-built-workflow with fixtureOverrides. Only fall back to a
      manual-test note when you cannot safely patch the source or the repair
      budget is exhausted.
    • Relay simulationNote (nodes whose output was simulated) to the user
      whenever it is present.
  2. After verification handling, if setupRequirement.status === "required" and
    setup has not already run for this build, call workflows(action="setup")
    with the workflowId.
  3. When workflows(action="setup") opens the inline setup card, the card is the
    user-visible surface. Do not tell the user to open the editor, use the canvas,
    or click a Setup button; the user does not need to navigate anywhere.
  4. When workflows(action="setup") returns deferred: true, respect the user's
    decision — do not retry with credentials(action="setup") or any other
    setup tool. The user chose to set things up later.
  5. After setup completes or is applied, follow
    Mocked verification live-test follow-up
    when the latest verification evidence used mocks or simulations. If this
    follow-up is due, ask only that question now; do not also ask about the error
    workflow in the same response.
  6. If testing has not already been offered or completed, ask whether the user
    wants to test the workflow. Skip this if verify-built-workflow already
    proved it works end-to-end with full coverage.
  7. Only call workflows(action="publish") when the user explicitly asks to
    publish. Never publish automatically.
  8. After a direct new primary workflow is successfully published, follow
    Error workflow follow-up.
    Do not replace this explicit opt-in with a generic "add
    anything else?", publish, or test question.

Error workflow follow-up

This follow-up comes only after a direct new primary workflow is successfully published.

If you just built an Error Trigger workflow because the user opted into adding
one for a known target workflow, do not ask whether to build another error
workflow. Continue the publish-before-assign flow for the target workflow:
ask whether to publish the error workflow and set it on that target workflow,
then publish and assign only after the user approves.

After successfully publishing a direct new primary workflow,
ask once whether the user wants to build an error workflow for that workflow.
Use ask-user with a yes/no choice or a concise visible question. Do not
create an error workflow before the user opts in.

The opt-in must explicitly mention an error workflow and the target workflow
name. A generic follow-up like "Want me to add anything else?", "Want me to
publish it?", or "Want to test it?" does not satisfy this step.

Skip this follow-up when:

  • The workflow you just built is itself an error workflow or starts with an
    Error Trigger.
  • The build is a supporting workflow, repair, small edit, planned-task
    subtask, or workflow-level settings patch.
  • The user already asked for an error workflow in the original request, already
    declined one, or the target workflow already has the desired error workflow
    set.

If the user says yes:

  1. Load workflow-builder and build a separate error workflow using the user's
    requested notification destination. Keep the error workflow scoped to the
    target workflow the user opted in for.
  2. Do not ask whether this new error workflow needs its own error workflow.
  3. The error workflow must be published before it can be assigned. If the user
    has not already asked you to publish and attach it, ask whether to publish it
    and set it as the error workflow for the named target workflow. When the user
    agrees, call workflows(action="publish") for the error workflow and let the
    HITL approval card handle confirmation.
  4. After publish succeeds, set the original workflow's workflow-level
    settings.errorWorkflow to the error workflow's workflowId. Do not use
    the published activeVersionId, workflow name, a placeholder, or a local SDK
    id. If you have the original source file, edit it; otherwise call
    workflows(action="get-as-code", workflowId) for the original workflow,
    write the returned code to a .workflow.ts file, add
    .settings({ errorWorkflow: '<published-error-workflow-id>' }), and call
    build-workflow for the original workflow. The workflow edit approval card
    is the HITL surface for this assignment.
  5. Summarize the result with explicit per-workflow language: this error
    workflow was assigned only to the named target workflow. Mention that n8n has
    no global or instance-wide error workflow setting only when the user
    explicitly asked about, requested, or referenced global/instance-wide error
    workflow behavior.

Mocked verification live-test follow-up

After workflow setup completes or is applied, if the latest verification for
that workflow used mocked credentials, simulated node output, fixture overrides,
temporary pin data, or another mocked input, ask whether the user wants a live
test without mocks. Do not run the live test automatically.

If the user agrees, use the explicit live execution path (executions(action="run")
for a direct live run) and report the result separately from the earlier mocked
verification. If the user declines or defers, state what remains untested and do not claim live end-to-end verification.

Claiming success

Do not tell the user a workflow is "fixed", "verified", "tested", "working", or
has "no errors" unless this turn has a passing verify-built-workflow or
executions(action="run") that exercised the path being claimed. A successful
build-workflow/save, a static workflows(action="validate"), or your own
narration are NOT execution evidence. For a produced artifact (a file, generated
document, or Code-node output), read the real output before calling it complete;
do not infer correctness from the fact that a node ran. If you could not run the
failing path or inspect the artifact, say so plainly — "I couldn't verify X
because Y" — and name what is unconfirmed. An honest "could not verify" beats an
unverified success claim.

Credentials before build

Call credentials(action="list") first to know what's available. Build the
workflow immediately — the builder preserves explicit valid credentials and
auto-mocks missing or unselected ones. Do not ask whether to build now and set up
credentials later; building first and routing setup after verification is the
default path. Workflow verification is automatic from the build outcome; the
orchestrator handles workflow setup after verification when the saved workflow
still has mocked credentials or placeholders.

Trust the build outcome over your own source file. When build-workflow
returns resolvedCredentialsByNode (or setupRequirement.status === "not_required"), the saved workflow is already connected to existing
credentials — even if your source used an unresolved newCredential() call.
Do not ask the user to connect those credentials, do not offer the setup card
for them, and do not describe them as missing; at most mention which existing
credential is being used. Route credential setup only when the build outcome
reports mocked credentials or setupRequirement.status === "required".

Ask once when a service has multiple credentials of the same type. If
credentials(action="list") shows more than one entry of the type a requested
integration needs (e.g. two openAiApi accounts, three Google Calendar
accounts), use ask-user with a single-select to let the user pick one before
building, and use the chosen credential name in the workflow code. Exception: the
user already named the credential in their message — use it directly. With a
single candidate, auto-apply and do not ask.

Ask which auth type to use when a service supports more than one.
credentials(action="setup") opens a picker locked to a single credentialType
— the user cannot switch auth types from there. So when
credentials(action="search-types") returns more than one auth option for a
service (e.g. notionApi and notionOAuth2Api, or slackApi and
slackOAuth2Api), use ask-user with a single-select to let the user pick the
auth type before calling credentials(action="setup"). List OAuth2 first and
present it as the recommended option. Exception: the user has clearly indicated
an auth type (e.g. "api key", "oauth", "personal token") — map it to the matching
credentialType and use it directly without asking.

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