io.usefulapi/lob
REMOTE · LOB.USEFULAPI.IO · SCANNED SEP 21
Verify US & international addresses and send physical mail (postcards, letters, checks) via Lob.
Available components
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security78
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation is enforced on tool calls, advertised via RFC 9728 protected-resource metadata. Discovery is public, which costs nothing: no tool can be invoked without a token. View diagnostics → Pass
- HTTPS enforcement could not be verified: the plaintext port answered with HTTP 401, which proves neither a plaintext path nor enforcement. View diagnostics → Unverified
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
- The authorisation server offers only Dynamic Client Registration (RFC 7591), which MCP 2026-07-28 deprecated in favour of Client ID Metadata Documents. View diagnostics → Partial
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability81
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 1929 tokens (~107/item across 18 items; 18 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management100
- No destabilizing schema changes in the last 30 days.Pass
Tool Coverage97
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 91% of tool parameters carry a description.Partial
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 18 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 18 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities60
- Spec-recency check failed: implements MCP spec 2025-06-18; the latest is 2026-07-28. See how to fix → Fail
How do I install the io.usefulapi/lob MCP server?
io.usefulapi/lob is a hosted endpoint at https://lob.usefulapi.io/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · lob.usefulapi.io
claude mcp add --transport http io-usefulapi-lob 'https://lob.usefulapi.io/mcp'
{
"mcpServers": {
"io-usefulapi-lob": {
"url": "https://lob.usefulapi.io/mcp"
}
}
} {
"servers": {
"io-usefulapi-lob": {
"type": "http",
"url": "https://lob.usefulapi.io/mcp"
}
}
} [mcp_servers.io-usefulapi-lob] url = "https://lob.usefulapi.io/mcp"
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"io-usefulapi-lob": {
"type": "remote",
"url": "https://lob.usefulapi.io/mcp",
"enabled": true
}
}
} openclaw mcp add io-usefulapi-lob --url 'https://lob.usefulapi.io/mcp' --transport streamable-http
mcp_servers:
io-usefulapi-lob:
url: "https://lob.usefulapi.io/mcp" {
"McpServers": {
"io-usefulapi-lob": {
"Transport": "http",
"Url": "https://lob.usefulapi.io/mcp"
}
}
} assistant mcp add io-usefulapi-lob -t streamable-http -u 'https://lob.usefulapi.io/mcp'
{
"mcpServers": {
"io-usefulapi-lob": {
"type": "http",
"url": "https://lob.usefulapi.io/mcp"
}
}
} The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 1 Sept 26 0
- Stability: 0.97 → pass security
- 31 Aug 26 0
- Stability: pass → 0.97 functional
- 26 Aug 26 +1
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 25 Aug 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 93 to 97. That category is still filling its 30-day observation window: 28 days of observed history at the previous scan, 29 at this one. The score rises as the window fills, whether or not the server changes.
- 11 Aug 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 2 Aug 26 0
- Authorization: unverified → pass ▲ security
- Transport: fail → pass ▲ security
- MCP protocol: unverified → fail ▼ functional
- Endpoint reachability: not serving MCP → reachable ▲ functional
- Tool coverage: unverified → 100 ▲ functional
- Stability: unverified → 0.20 ▲ functional
- 1 Aug 26 0
- Endpoint reachability: reachable → not serving MCP ▼ security
- Stability: 0.13 → unverified ▼ security
- Authorization: pass → unverified ▼ security
- Transport: pass → fail ▼ security
- Capabilities: fail → unverified ▼ functional
- Tool coverage: 100 → unverified ▼ functional
- 31 Jul 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 21 Sept 2026 · Probed https://lob.usefulapi.io/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=usefulapi.io | CN=WE1,O=Google Trust Services,C=US | 14 Sept 2026 | 13 Dec 2026 | ECDSA 256 | ECDSA-SHA256 | 69191ff21a4db00813d42abf339e3c92 |
| SANs: usefulapi.io, lob.usefulapi.io, *.lob.usefulapi.io | ||||||
| CN=WE1,O=Google Trust Services,C=US (CA) | CN=GTS Root R4,O=Google Trust Services LLC,C=US | 13 Dec 2023 | 20 Feb 2029 | ECDSA 256 | ECDSA-SHA384 | 7ff31977972c224a76155d13b6d685e3 |
| CN=GTS Root R4,O=Google Trust Services LLC,C=US (CA) | CN=GlobalSign Root CA,OU=Root CA,O=GlobalSign nv-sa,C=BE | 15 Nov 2023 | 28 Jan 2028 | ECDSA 384 | SHA256-RSA | 7fe530bf331343bedd821610493d8a1b |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of lob.usefulapi.io. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| io. | present | 57355 | 8 | Verified |
| usefulapi.io. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication Enforced and verified
The endpoint asked for a token and published valid RFC 9728 metadata describing how to get one.
| Result | Enforced and verified |
|---|---|
| Enforced | On tool calls |
| HTTP status | 200 |
WWW-Authenticate challenge Bearer realm="OAuth", resource_metadata="https://lob.usefulapi.io/.well-known/oauth-protected-resource/mcp", error="invalid_token", error_description="Missing or invalid access token"
Bearer realm="OAuth", resource_metadata="https://lob.usefulapi.io/.well-known/oauth-protected-resource/mcp", error="invalid_token", error_description="Missing or invalid access token"Protected resource metadata
| Document | https://lob.usefulapi.io/.well-known/oauth-protected-resource/mcp |
|---|---|
| Retrieved | Yes |
| Resource | https://lob.usefulapi.io/mcp |
| Authorisation server | https://lob.usefulapi.io |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://lob.usefulapi.io/mcp | Verified | 200 | |
| http (plaintext) | http://lob.usefulapi.io/mcp | Inconclusive | 401 |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
lob_cancel_postcard Cancel a scheduled postcard ~64
Cancel 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}.
| Name | Type | Req | Description |
|---|---|---|---|
| id | string | yes | Postcard id (psc_…) to cancel. |
No output schema declared.
No examples provided.
lob_create_address Save an address record ~168
Create 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.
| Name | Type | Req | Description |
|---|---|---|---|
| address_city | string | – | – |
| address_country | string | – | 2-letter ISO country code. Defaults to US. |
| address_line1 | string | yes | Primary street address. |
| address_line2 | string | – | Unit/suite/apt. |
| address_state | string | – | 2-letter state/province code. |
| address_zip | string | – | ZIP / postal code. |
| company | string | – | – |
| description | string | – | Internal label for this address. |
| name | string | – | Recipient name (required unless `company` is set). |
No output schema declared.
No examples provided.
lob_create_letter Send a letter (COSTS MONEY) ~257
⚠️ 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 `send_date`. Lob API: POST /v1/letters.
| Name | Type | Req | Description |
|---|---|---|---|
| address_placement | string | – | Where the recipient address is placed. |
| color | boolean | yes | true = color printing, false = black & white. |
| description | string | – | Internal label. |
| double_sided | boolean | – | Print on both sides. Default true. |
| file | string | yes | Letter body: HTML string, asset/PDF URL, or template id (tmpl_…). |
| from | – | yes | Return address (id or inline object). Required for letters. |
| merge_variables | object | – | Key/value data merged into HTML templates. |
| send_date | string | – | ISO-8601 date/time to schedule the send (future). Cancelable until then. |
| to | – | yes | Either an existing address id (adr_…) or an inline address object. |
No output schema declared.
No examples provided.
lob_create_postcard Send a postcard (COSTS MONEY) ~257
⚠️ 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 only before `send_date`. Lob API: POST /v1/postcards.
| Name | Type | Req | Description |
|---|---|---|---|
| back | string | yes | Back artwork: HTML string, asset URL, or template id (tmpl_…). |
| description | string | – | Internal label. |
| from | – | – | Return address (id or inline object). Optional. |
| front | string | yes | Front artwork: HTML string, asset URL, or template id (tmpl_…). |
| mail_type | string | – | USPS mail class. |
| merge_variables | object | – | Key/value data merged into HTML templates. |
| send_date | string | – | ISO-8601 date/time to schedule the send (future). Cancelable until then. |
| size | string | – | Postcard size. Default 4x6. |
| to | – | yes | Either an existing address id (adr_…) or an inline address object. |
No output schema declared.
No examples provided.
lob_get_address Get a saved address ~43
Retrieve a single saved address record by id. Lob API: GET /v1/addresses/{id}.
| Name | Type | Req | Description |
|---|---|---|---|
| id | string | yes | Address id (adr_…). |
No output schema declared.
No examples provided.
lob_get_check Get a check ~50
Retrieve a single check by id, including amount, status, and check number. Lob API: GET /v1/checks/{id}.
| Name | Type | Req | Description |
|---|---|---|---|
| id | string | yes | Check id (chk_…). |
No output schema declared.
No examples provided.
lob_get_letter Get a letter ~50
Retrieve a single letter by id, including status, PDF url, and tracking. Lob API: GET /v1/letters/{id}.
| Name | Type | Req | Description |
|---|---|---|---|
| id | string | yes | Letter id (ltr_…). |
No output schema declared.
No examples provided.
lob_get_postcard Get a postcard ~53
Retrieve a single postcard by id, including status, PDF url, and expected delivery. Lob API: GET /v1/postcards/{id}.
| Name | Type | Req | Description |
|---|---|---|---|
| id | string | yes | Postcard id (psc_…). |
No output schema declared.
No examples provided.
lob_list_addresses List saved addresses ~86
List saved address records, newest first. Lob API: GET /v1/addresses.
| Name | Type | Req | Description |
|---|---|---|---|
| after | string | – | Cursor for the next page (from a previous response's next_url). |
| before | string | – | Cursor for the previous page (from a previous response's previous_url). |
| limit | integer | – | Max results per page (1–100). Default 10. |
No output schema declared.
No examples provided.
lob_list_checks List checks ~87
List sent/scheduled checks, newest first. Lob API: GET /v1/checks.
| Name | Type | Req | Description |
|---|---|---|---|
| after | string | – | Cursor for the next page (from a previous response's next_url). |
| before | string | – | Cursor for the previous page (from a previous response's previous_url). |
| limit | integer | – | Max results per page (1–100). Default 10. |
No output schema declared.
No examples provided.
lob_list_letters List letters ~87
List sent/scheduled letters, newest first. Lob API: GET /v1/letters.
| Name | Type | Req | Description |
|---|---|---|---|
| after | string | – | Cursor for the next page (from a previous response's next_url). |
| before | string | – | Cursor for the previous page (from a previous response's previous_url). |
| limit | integer | – | Max results per page (1–100). Default 10. |
No output schema declared.
No examples provided.
lob_list_postcards List postcards ~88
List sent/scheduled postcards, newest first. Lob API: GET /v1/postcards.
| Name | Type | Req | Description |
|---|---|---|---|
| after | string | – | Cursor for the next page (from a previous response's next_url). |
| before | string | – | Cursor for the previous page (from a previous response's previous_url). |
| limit | integer | – | Max results per page (1–100). Default 10. |
No output schema declared.
No examples provided.
lob_list_self_mailers List self-mailers ~92
List sent/scheduled self-mailers, newest first. Lob API: GET /v1/self_mailers.
| Name | Type | Req | Description |
|---|---|---|---|
| after | string | – | Cursor for the next page (from a previous response's next_url). |
| before | string | – | Cursor for the previous page (from a previous response's previous_url). |
| limit | integer | – | Max results per page (1–100). Default 10. |
No output schema declared.
No examples provided.
lob_list_templates List templates ~88
List saved HTML templates usable as postcard/letter artwork. Lob API: GET /v1/templates.
| Name | Type | Req | Description |
|---|---|---|---|
| after | string | – | Cursor for the next page (from a previous response's next_url). |
| before | string | – | Cursor for the previous page (from a previous response's previous_url). |
| limit | integer | – | Max results per page (1–100). Default 10. |
No output schema declared.
No examples provided.
lob_us_autocomplete Autocomplete a US address ~101
Suggest complete US addresses from a partial primary line — useful for address entry. Non-mutating. Lob API: POST /v1/us_autocompletions.
| Name | Type | Req | Description |
|---|---|---|---|
| address_prefix | string | yes | Partial primary line, e.g. '185 Berr'. |
| city | string | – | Optional city to narrow suggestions. |
| state | string | – | Optional 2-letter state to narrow suggestions. |
| zip_code | string | – | Optional ZIP to narrow suggestions. |
No output schema declared.
No examples provided.
lob_us_zip_lookup Look up a US ZIP code ~61
Return the cities and state associated with a US ZIP code. Non-mutating. Lob API: POST /v1/us_zip_lookups.
| Name | Type | Req | Description |
|---|---|---|---|
| zip_code | string | yes | A 5-digit US ZIP code, e.g. '94107'. |
No output schema declared.
No examples provided.
lob_verify_intl_address Verify an international address ~123
Validate & standardize a non-US address. `country` (2-letter ISO code) is required. Non-mutating (no mail sent). Lob API: POST /v1/intl_verifications.
| Name | Type | Req | Description |
|---|---|---|---|
| city | string | – | – |
| country | string | yes | 2-letter ISO country code, e.g. 'GB', 'DE', 'CA'. |
| postal_code | string | – | – |
| primary_line | string | yes | Primary delivery line. |
| secondary_line | string | – | – |
| state | string | – | State / province / region. |
No output schema declared.
No examples provided.
lob_verify_us_address Verify a US address ~174
Validate & 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.
| Name | Type | Req | Description |
|---|---|---|---|
| address | string | – | Freeform single-line address (alternative to the structured fields). |
| city | string | – | – |
| primary_line | string | – | Primary delivery line, e.g. '210 King Street'. |
| secondary_line | string | – | Secondary line, e.g. 'Suite 6100'. |
| state | string | – | 2-letter state code, e.g. 'CA'. |
| zip_code | string | – | 5-digit or ZIP+4. |
No output schema declared.
No examples provided.
What is the io.usefulapi/lob MCP server?
io.usefulapi/lob is an MCP server listed in the public MCP registry as io.usefulapi/lob. Verify US & international addresses and send physical mail (postcards, letters, checks) via Lob. This page covers its hosted endpoint (https://lob.usefulapi.io/mcp).
Is the io.usefulapi/lob MCP server safe to use?
io.usefulapi/lob scores 86 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the io.usefulapi/lob MCP server expose?
io.usefulapi/lob exposes 18 tools: lob_verify_us_address, lob_verify_intl_address, lob_us_zip_lookup, lob_us_autocomplete, lob_list_postcards, and 13 more. Their descriptions and schemas cost roughly 1,929 tokens of context every time the server is loaded.
Does the io.usefulapi/lob MCP server require authentication?
Yes. io.usefulapi/lob asked us for credentials when we connected, so you will need to authorise it in your MCP client before it can do anything.
Is the io.usefulapi/lob MCP server still maintained?
io.usefulapi/lob is still listed as active in the MCP registry. We last reached this channel on 21 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.