Save an address to the Lob address book so it can be reused by ID (adr_…) when creating mail pieces. Stored addresses are NOT automatically verified — call lob_us_verifications_create or lob_intl_verifications_create separately if needed.

List addresses stored in your Lob address book. For 'how many addresses?' counts, pass include: ['total_count'] with limit: 1. Filter by date_created (e.g. { gt: '<iso>' } for recently-added) or metadata.

Retrieve a single saved address by ID.

Delete a saved address from the address book. Does not affect mail pieces already created with it.

Verify, correct, and standardize a single US address. Returns deliverability status, USPS-formatted components, geolocation (lat/lng), and county info.

Retrieve a previously-created US verification by ID.

Suggest completed US addresses from a partial input — useful for typeahead UX. Returns up to 10 suggestions.

Verify a single non-US address. Returns deliverability status and standardized components for the destination country.

Verify up to 1,000 US addresses in a single request. Returns one verification result per input, in the same order.

Verify up to 1,000 non-US addresses in a single request.

Validate a person/business name against a US address. Returns whether the recipient is associated with the address.

Render a Lob proof PDF for a postcard without charging or sending. Returns a confirmation_token to pass to lob_postcards_create. The token is required in live mode (LOB_LIVE_MODE=true). Token TTL: LOB_CONFIRMATION_TTL_SECONDS (default 600). Sizes: 4x6 (default), 6x9, 6x11.

Commit a postcard send. Billable in live mode: produces real physical mail and is charged to your Lob account. In live mode, requires a confirmation_token from lob_postcards_preview that matches the current payload. In test mode, the token is optional (dev ergonomics).

List postcards on your Lob account. For 'how many postcards?' counts, pass include: ['total_count'] with limit: 1 — never paginate to count. Filter by date_created (e.g. { gt: '<iso>' } for 'last N days'), send_date, size, mail_type, scheduled, or metadata. Default sort is most-recent first.

Retrieve a single postcard by ID.

Cancel a postcard before its send_date. Only works while the postcard is still in a cancellable state — production-locked pieces cannot be cancelled.

Render a Lob proof PDF for a letter without charging or sending. Returns a confirmation_token to pass to lob_letters_create. Required in live mode.

Commit a letter send. Billable in live mode. Requires a confirmation_token from lob_letters_preview that matches the current payload (live mode only).

List letters on your Lob account. For 'how many letters?' counts, pass include: ['total_count'] with limit: 1 — never paginate to count. Filter by date_created (e.g. { gt: '<iso>' } for 'last N days'), send_date, mail_type, color, scheduled, or metadata. Default sort is most-recent first.

Retrieve a single letter by ID.

Cancel a letter before its send_date. Production-locked letters cannot be cancelled.

Render a Lob proof PDF for a self-mailer without charging or sending. Returns a confirmation_token to pass to lob_self_mailers_create. Required in live mode.

Commit a self-mailer send. Billable in live mode. Requires a confirmation_token from lob_self_mailers_preview that matches the current payload (live mode only). Sizes: 6x18_bifold (default), 11x9_bifold.

List self-mailers on your Lob account. For 'how many?' counts, pass include: ['total_count'] with limit: 1 — never paginate to count. Filter by date_created (e.g. { gt: '<iso>' } for 'last N days'), size, mail_type, scheduled, or metadata. Default sort is most-recent first.

Retrieve a single self-mailer by ID.

Cancel a self-mailer before its send_date.

Validate a check payload and return a textual summary. Lob does not produce check proofs, so no PDF is rendered. Returns a confirmation_token to pass to lob_checks_create — required in live mode. The token binds the payload: committing a different amount or recipient is rejected.

Commit a check send. HIGH IMPACT: incurs Lob fees AND draws the check amount from the linked bank account when cashed. Requires a verified bank account ID (bank_…). In live mode, requires a confirmation_token from lob_checks_preview that matches the current payload. If LOB_REQUIRE_ELICITATION_FOR_CHECKS_OVER_USD is set and amount exceeds it, an elicitation form must be confirmed by the user before dispatch.

For the bottom of the check page, Lob requires exactly one of message (plain text, max 400 chars) or check_bottom (custom template / HTML / PDF, typically paired with merge_variables).

List checks on your Lob account. For 'how many checks?' counts, pass include: ['total_count'] with limit: 1 — never paginate to count. Filter by date_created (e.g. { gt: '<iso>' } for 'last N days'), send_date, scheduled, or metadata. Default sort is most-recent first.

Retrieve a single check by ID.

Cancel a check before its send_date. Once printed/mailed, checks cannot be cancelled — you would need to issue a stop-payment with the bank.

Create a reusable HTML template that can be referenced by ID (tmpl_…) when creating mail pieces. Supports Handlebars-style {{variables}} for runtime substitution.

List templates on your Lob account. By default returns slim records (no HTML body) — Lob template HTML can be many MB per entry and quickly overwhelms LLM context. Pass include_html: true to get the full HTML, or use lob_templates_get(id) for a single template. For 'how many templates?' counts, pass include: ['total_count'] with limit: 1. To find a template by name or metadata, use lob_templates_search.

Retrieve a single template (including its published version) by ID.

Find templates by description substring (case-insensitive) and/or by Lob metadata. Pages through /templates server-side and returns slim matches (no HTML — use lob_templates_get(id) for the full body). Useful when you know the template by name but not by tmpl_… id.

Update a template's metadata or published version. To publish a new version, set published_version to a version ID (vrsn_…).

Delete a template. Mail pieces already created from it are unaffected; future references will fail.

Add a new version of a template's HTML. Creating a new version does NOT automatically publish it — use lob_templates_update to set published_version.

List all versions of a template. Slim by default (no HTML); pass include_html: true to get the full HTML body of each version, or use lob_template_versions_get(template_id, version_id). For 'how many versions?' counts, pass include: ['total_count'] with limit: 1.

Retrieve a specific version of a template.

Update the description of a template version. HTML cannot be modified after creation.

Delete a template version. Cannot delete the currently published version.

Create a campaign — a container for batched mail-piece sends with a shared creative, schedule, and audience. Creating a campaign does not by itself send mail; you trigger sends per Lob docs.

List campaigns on your Lob account. For 'how many campaigns?' counts, pass include: ['total_count'] with limit: 1. Filter by date_created or metadata.

Retrieve a single campaign by ID.

Update a campaign's metadata or schedule before it has been sent.

Delete a campaign. Only allowed before send.

Create a campaign creative — the artwork (front/back / inside/outside / file) used by a campaign for postcards, letters, or self-mailers. Important: unlike lob_postcards_create and the other mail-piece create tools, Lob's /v1/creatives endpoint does NOT accept HTML strings, remote URLs, or inline PDFs in the content fields — it accepts ONLY a Lob template ID (tmpl_…). To use a URL or HTML as creative content, first call lob_templates_create to upload it as a template, then pass the resulting tmpl_… here. Required by resource_type: postcard → front + back; letter → file + from; self_mailer → inside + outside. Live-mode key required.

Retrieve a single creative by ID.

Update a creative's description or metadata.

Delete a creative.

Upload a buckslip — an 8.75"×3.75" promotional insert that can be included in letters. front must be a publicly-reachable PDF URL (or base64 data URI). Inventory is reserved on Lob's side and consumed when ordered. Note: Lob's buckslips API only accepts multipart/form-data, so this tool sends the body as multipart.

List buckslip inventory on your account. For 'how many buckslips?' counts, pass include: ['total_count'] with limit: 1. Filter by date_created or metadata.

Retrieve a single buckslip by ID.

Validate a buckslip-inventory-order payload and return a textual summary. Returns a confirmation_token to pass to lob_buckslip_orders_create — required in live mode.

Commit a buckslip-inventory order. Billable in live mode — Lob prints and stocks the requested quantity. Requires a confirmation_token from lob_buckslip_orders_preview that matches the current payload (live mode only). If LOB_REQUIRE_ELICITATION_FOR_BULK_OVER_PIECES is set and quantity_ordered exceeds it, an elicitation form must be confirmed.

List orders for a specific buckslip. Note: this nested endpoint does NOT accept include: ['total_count'] — counting requires walking pages, or read aggregate fields (quantity_ordered, quantity_remaining) off the parent via lob_buckslips_get.

Upload a card — a small printed insert (e.g. business card, plastic gift card) that can be inserted with a letter.

List card inventory on your account. For 'how many cards?' counts, pass include: ['total_count'] with limit: 1. Filter by date_created or metadata.

Retrieve a single card by ID.

Validate a card-inventory-order payload and return a textual summary. Returns a confirmation_token to pass to lob_card_orders_create — required in live mode.

Commit a card-inventory order. Billable in live mode — Lob prints and stocks the requested quantity. Requires a confirmation_token from lob_card_orders_preview that matches the current payload (live mode only). If LOB_REQUIRE_ELICITATION_FOR_BULK_OVER_PIECES is set and quantity exceeds it, an elicitation form must be confirmed.

List orders for a specific card. Note: this nested endpoint does NOT accept include: ['total_count'] — counting requires walking pages, or read aggregate fields off the parent via lob_cards_get.

List QR-code scan / analytics events for QR codes embedded in your mail pieces. For 'how many scans?' counts, pass include: ['total_count'] with limit: 1. Filter by date_scanned (e.g. { gt: '<iso>' } for 'last N days'), resource_id (scans tied to a specific mail piece), or campaign_id (scans for a whole campaign).

Create a proof — a PDF preview of how a resource (postcard, letter, self-mailer) will print — for review before committing to a mail send. Pass resource_parameters with the same shape you would pass to the underlying create endpoint (e.g. { front, back, to } for a postcard). Note: the lob_*_preview tools call this endpoint internally; this raw tool is exposed for advanced use cases.

Retrieve a resource proof by ID, including a URL to download the proof PDF.

Approve or reject a resource proof.

Register a bank account that can be used to draw checks. Requires routing number, account number, account type, and signatory. Bank accounts must be verified (lob_bank_accounts_verify) before use in lob_checks_create.

List bank accounts on your Lob account. For 'how many bank accounts?' counts, pass include: ['total_count'] with limit: 1.

Retrieve a single bank account by ID.

Remove a bank account. Pending checks drawn against it will continue to clear.

Verify a bank account by submitting two micro-deposit amounts (in cents) that Lob deposited into the account during registration. Required before the account can be used to draw checks.

Subscribe an HTTPS endpoint to receive Lob event notifications (e.g. 'postcard.mailed', 'letter.in_transit', 'check.delivered'). The endpoint must respond with 2xx within 5 seconds.

List webhook subscriptions on your account. Note: Lob's /webhooks does NOT support include: ['total_count'] — for a count, just inspect data.length (webhook lists are small).

Retrieve a single webhook subscription by ID.

Update a webhook's URL, event subscriptions, or description. Note: the disabled flag on the response is Lob-managed (e.g. Lob auto-disables webhooks whose delivery URL consistently fails) and is not settable by callers.

Delete a webhook subscription.

Return the design specification (dimensions, bleed, safe area, no-print zones, file requirements) for a Lob mail-piece variant. Call this BEFORE generating artwork so the design respects Lob's auto-stamped address blocks. Same data is also available as MCP resources at lob://specs/{mail_type}/{variant}.json.