Spec Driven Development
MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.
Description from the maker (original English)
Verify US & international addresses and send physical mail (postcards, letters, checks) via Lob.
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We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.
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Works in Claude on the web, desktop and mobile:
https://lob.usefulapi.io/mcpRun this in your terminal
claude mcp add --transport http lob https://lob.usefulapi.io/mcpPaste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json
{
"mcpServers": {
"lob": {
"url": "https://lob.usefulapi.io/mcp"
}
}
}Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.
Paste into .vscode/mcp.json in your project
{
"servers": {
"lob": {
"type": "http",
"url": "https://lob.usefulapi.io/mcp"
}
}
}Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.
ChatGPT connects only to servers on the internet:
https://lob.usefulapi.io/mcpMenu names can differ slightly by plan and over time.
Your choice stays on this device in a cookie; no account needed.
These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.
Tool names and descriptions exactly as the server reported them on Nov 6, 2026. The maker wrote them, not us; we show them as plain text.
lob_verify_us_addressValidate & standardize a US address, returning deliverability, corrected components, and a confidence score. Pass either a single freeform `address` string OR structured `primary_line`/`city`/`state`/`zip_code`. Non-mutating (no mail sent). Lob API: POST /v1/us_verifications.
lob_verify_intl_addressValidate & standardize a non-US address. `country` (2-letter ISO code) is required. Non-mutating (no mail sent). Lob API: POST /v1/intl_verifications.
lob_us_zip_lookupReturn the cities and state associated with a US ZIP code. Non-mutating. Lob API: POST /v1/us_zip_lookups.
lob_us_autocompleteSuggest complete US addresses from a partial primary line — useful for address entry. Non-mutating. Lob API: POST /v1/us_autocompletions.
lob_list_postcardsList sent/scheduled postcards, newest first. Lob API: GET /v1/postcards.
lob_get_postcardRetrieve a single postcard by id, including status, PDF url, and expected delivery. Lob API: GET /v1/postcards/{id}.
lob_list_lettersList sent/scheduled letters, newest first. Lob API: GET /v1/letters.
lob_get_letterRetrieve a single letter by id, including status, PDF url, and tracking. Lob API: GET /v1/letters/{id}.
lob_list_checksList sent/scheduled checks, newest first. Lob API: GET /v1/checks.
lob_get_checkRetrieve a single check by id, including amount, status, and check number. Lob API: GET /v1/checks/{id}.
lob_list_self_mailersList sent/scheduled self-mailers, newest first. Lob API: GET /v1/self_mailers.
lob_list_addressesList saved address records, newest first. Lob API: GET /v1/addresses.
lob_get_addressRetrieve a single saved address record by id. Lob API: GET /v1/addresses/{id}.
lob_list_templatesList saved HTML templates usable as postcard/letter artwork. Lob API: GET /v1/templates.
lob_create_addressCreate a reusable saved address record (does NOT send any mail). Returns an address id (adr_…) usable as `to`/`from` in mail tools. Lob API: POST /v1/addresses.
lob_create_postcard⚠️ SENDS A REAL POSTCARD and charges your Lob account (use a test_ key to avoid real mail/charges). `to` and `from` accept an existing address id (adr_…) or an inline address object. `front`/`back` accept an HTML string, a hosted asset URL, or a template id (tmpl_…). Cancelable o
lob_create_letter⚠️ SENDS A REAL LETTER and charges your Lob account (use a test_ key to avoid real mail/charges). `to`/`from` accept an address id (adr_…) or inline object. `file` accepts an HTML string, a hosted PDF/URL, or a template id (tmpl_…). `color` is required. Cancelable only before `se
lob_cancel_postcardCancel a postcard before its send_date so it is never mailed (and not billed). Fails if the send window has passed. Lob API: DELETE /v1/postcards/{id}.
We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 6, 2026
The registry name was verified against the domain usefulapi.io (the registry checks domain ownership)
We have not read this repo from GitHub yet
We have not read this repo from GitHub yet
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Read 18 tool descriptions and found no hidden instructions to the AI
Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.
It passed 3 of 3 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.
The registry does not list a required key, though some servers ask you to sign in on first use.
It runs in the maker’s cloud. Connect over the internet with nothing to install, but what you send passes through the maker’s servers.
The GitHub repo last changed –, and the latest version (1.36.3) reached the registry yesterday.
Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT in developer mode.
In the same category: Spec Driven Development, Remote Desktop Commander, debuff
Servers in the same category from other makers, sorted by stars.
Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi
MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.
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Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.
Verify addresses and send physical mail via Lob, from Claude, Cursor, or any MCP client. Hosted, no local install — connect with your Lob API key.
Live endpoint: https://lob.usefulapi.io/mcp · Homepage: https://usefulapi.io/lob
https://lob.usefulapi.io/mcp.claude mcp add --transport http lob https://lob.usefulapi.io/mcp, then run /mcp to log in.{
"mcpServers": { "lob": { "url": "https://lob.usefulapi.io/mcp" } } }
Add only the URL. Do not add an Authorization header or an API key to the client config: the server signs you in with OAuth, and the login page asks for your Lob credentials.
Step-by-step setup, where to find your credentials, and FAQ: https://usefulapi.io/lob/
On first connect you'll paste your Lob API key. It's validated, stored per-user, and scoped to you.
| Tool | Type | What it does |
|---|---|---|
lob_verify_us_address | read | Verify a US address |
lob_verify_intl_address | read | Verify an international address |
lob_us_zip_lookup | read | Look up a US ZIP code |
lob_us_autocomplete | read | Autocomplete a US address |
lob_list_postcards | read | List postcards |
lob_get_postcard | read | Get a postcard |
lob_list_letters | read | List letters |
lob_get_letter | read | Get a letter |
lob_list_checks | read | List checks |
lob_get_check | read | Get a check |
lob_list_self_mailers | read | List self-mailers |
lob_list_addresses | read | List saved addresses |
lob_get_address | read | Get a saved address |
lob_list_templates | read | List templates |
lob_create_address | write | Save an address record |
lob_create_postcard | write | Send a postcard (COSTS MONEY) |
lob_create_letter | write | Send a letter (COSTS MONEY) |
lob_cancel_postcard | write | Cancel a scheduled postcard |
lob_usage_status | meta | Usage status (free-tier meter) |
lob_request_feature | meta | Request a missing feature |
lob_upgrade | meta | Upgrade to Pro or Pro+ |
lob_cancel_subscription | meta | Cancel the Pro subscription |
read tools are read-only; write tools mutate data (clients should confirm them); meta tools report usage, manage your subscription or send a feature request.
| Plan | Price | Limit |
|---|---|---|
| Free | $0 | 50 tool calls / month |
| Pro | $9/mo or $90/yr (2 months free) | Unlimited* |
\*Pro has a fair use limit of 10,000 tool calls a month on this server. For more, write to support@usefulapi.io.
Pro covers this server only. Subscribe with lob_upgrade (it returns a Stripe Checkout link). Cancel any time with lob_cancel_subscription: Pro continues to the end of the paid period, with no refund for the current period, and running lob_upgrade before then undoes the cancel. Or write to support@usefulapi.io.
MIT — see LICENSE. Documentation only; the server is hosted.