npubmail
MCPB · NPUBMAIL-MCP-0.2.1.MCPB
Email inbox for AI agents, owned by a Nostr key. No signup or API key. Receive codes, read, send.
Available components
Last scanned (10 hours ago)
Scores higher than 83% of MCPB servers
Category Communication
How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. How we score → Why this is hard to score →
Supply Chain Security0
- No malware scan is available for this kind of package: the supply-chain vendors we use do not cover it. This is a permanent gap in our coverage, not a finding about the package.Unverified
- Known CVEs could not be checked: we found no dependency list to check in this bundle: either it runs a compiled binary, whose bundled manifests we do not read, or none of the package.json, requirements.txt, pyproject.toml or uv.lock files it ships for its runtime declares a dependency we can read (a requirements.txt that only points at a setup.py project, a local path, or a nested requirements file we cannot follow counts as none).Unverified
- Install-script risk not yet assessed.Unverified
- Dependency health could not be checked: we found no dependency list to check in this bundle: either it runs a compiled binary, whose bundled manifests we do not read, or none of the package.json, requirements.txt, pyproject.toml or uv.lock files it ships for its runtime declares a dependency we can read (a requirements.txt that only points at a setup.py project, a local path, or a nested requirements file we cannot follow counts as none).Unverified
Provenance & Transparency45
- Source repository is publicly reachable at the declared URL. View diagnostics → Pass
- Provenance check failed: no build-provenance attestation is published. See how to fix → View diagnostics → Fail
- Clear OSI-approved license (MIT).Pass
- Actively maintained (last published 15 days ago).Pass
- Disclosure check failed: no security disclosure policy was found in the source repository. See how to fix → Fail
Schema Quality & AI Usability78
- AI-judged instruction clarity (excellent).Pass
- Tool/resource definitions use about 1343 tokens (~83/item across 16 items; 16 tools + 0 resources), lean.Pass
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management67
- Stability observed for 20 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
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 Safety75
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- 0 of 3 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation; "delete_email" implies "delete" and declares no destructiveHint at all, which the MCP spec reads as destructive by default. See how to fix → Fail
- An AI judge read all 17 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
Unverified: 1 category
A category scored 0 because we could not verify it: a data source with nothing on this package, evidence we could not reach, or a check we could not run. We only credit what we can confirm.
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.
- 24 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 63 to 67. That category is still filling its 30-day observation window: 19 days of observed history at the previous scan, 20 at this one. The score rises as the window fills, whether or not the server changes.
- 22 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 57 to 60. That category is still filling its 30-day observation window: 17 days of observed history at the previous scan, 18 at this one. The score rises as the window fills, whether or not the server changes.
- 20 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 50 to 53. That category is still filling its 30-day observation window: 15 days of observed history at the previous scan, 16 at this one. The score rises as the window fills, whether or not the server changes.
- 18 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 43 to 47. That category is still filling its 30-day observation window: 13 days of observed history at the previous scan, 14 at this one. The score rises as the window fills, whether or not the server changes.
- 16 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 37 to 40. That category is still filling its 30-day observation window: 11 days of observed history at the previous scan, 12 at this one. The score rises as the window fills, whether or not the server changes.
- 14 Oct 26 +35
- Injection markers: unverified → pass ▲ security
- Tool coverage: unverified → 100 ▲ functional
- Stability: unverified → 0.33 ▲ functional
- MCP protocol: unverified → pass ▲ functional
- 12 Oct 26 0
- Package version: 0.2.0 → 0.2.1 functional
- 9 Oct 26 −30
- Tool safety: pass → unverified ▼ security
- Stability: Stability not yet verified: we do not have a sandbox capture of the MCP schema this version of the package serves yet. security
- Capabilities: pass → unverified ▼ functional
- Tool coverage: 100 → unverified ▼ functional
- First check of Schema quality: unverified functional
- Package version: 0.2.0 → 0.2.1 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 24 Oct 2026 · Analysed mcpb/https://github.com/obvioussummer46/npubmail/releases/download/v0.2.1/npubmail-mcp-0.2.1.mcpb@0.2.1
Provenance No attestation
The registry publishes no build provenance for this version, so there is nothing to verify.
| Result | No attestation |
|---|---|
| Ecosystem | mcpb |
| Reason | No attestation published |
Background: How many MCP packages publish verified provenance →
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 →
buy_storage ~97
Keep mail longer than 7 days. Answers with a Lightning invoice first; after it is paid, call again with payment_id.
| Name | Type | Req | Description |
|---|---|---|---|
| days | integer | yes | retention tier in days, e.g. 30, 90, 365 (see storage_plan) |
| months | integer | – | how many 30-day periods (default 1) |
| payment_id | string | – | after paying: the payment_id from the payment-required answer |
No output schema declared.
No examples provided.
create_alias ~119
Create a disposable address that delivers into your mailbox and expires. Use one per signup; set allow_from to the service's domain so nothing else can reach it. Returns a cursor for wait_for_code.
| Name | Type | Req | Description |
|---|---|---|---|
| allow_from | string | – | only accept mail from these sender domains, comma-separated (e.g. github.com). Strongly recommended for signups |
| label | string | – | note to self, e.g. the service you are signing up for |
| ttl_hours | integer | – | hours until the address stops accepting mail (default 24) |
No output schema declared.
No examples provided.
delete_email ~22
Delete an email from your mailbox.
| Name | Type | Req | Description |
|---|---|---|---|
| id | string | yes | – |
No output schema declared.
No examples provided.
invoice_status ~35
Check whether a payment request (payment_id) has been paid.
| Name | Type | Req | Description |
|---|---|---|---|
| id | string | yes | payment_id from a payment-required answer |
No output schema declared.
No examples provided.
list_emails ~49
List received emails, newest first, with extracted codes and sender verification.
| Name | Type | Req | Description |
|---|---|---|---|
| after | string | – | only messages newer than this id |
| limit | integer | – | max messages (default 20) |
No output schema declared.
No examples provided.
outbox ~43
Sent emails still waiting for a retry (recipient server said 'try later'), plus your bounce count. Final failures arrive in your inbox as 'Undeliverable: ...'.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
pay_invoice ~68
Built-in wallet (optional): pay a Lightning invoice, within the spending limits. Paying is spending money: only pay what your principal allows. When set up, send_email pays npubmail's own invoices with it automatically (within limits).
| Name | Type | Req | Description |
|---|---|---|---|
| bolt11 | string | yes | Lightning invoice to pay |
No output schema declared.
No examples provided.
read_email ~58
Read one email: text body, links (verify/confirm links flagged as action), codes, SPF/DKIM result and safety warnings.
| Name | Type | Req | Description |
|---|---|---|---|
| html | boolean | – | also return the raw HTML body |
| id | string | yes | message id |
No output schema declared.
No examples provided.
send_email ~203
Send a plain-text email from your primary address. Recipients who never wrote to you cost sats: the first call answers PAYMENT REQUIRED with a Lightning invoice; after it is paid, call again with the same arguments plus payment_id. Per recipient: ok=true delivered; queued=true the receiving server asked to retry later and npubmail retries automatically for ~2 days (do not resend); ok=false without queued is a permanent failure. Daily recipient quota applies; too many bounces suspend sending. Only send what your principal asked for.
| Name | Type | Req | Description |
|---|---|---|---|
| from_name | string | – | display name for the From header |
| in_reply_to | string | – | Message-ID being answered, to keep threading |
| payment_id | string | – | after paying a PAYMENT REQUIRED invoice for this exact message |
| reply_to | string | – | – |
| subject | string | yes | – |
| text | string | yes | plain-text body |
| to | null|array | yes | recipient addresses (1-10) |
No output schema declared.
No examples provided.
set_lightning_address ~95
Optional. Make your mailbox addresses (name@domain, npub@domain) also work as Lightning addresses that forward to a Lightning address you already have (any wallet). npubmail only relays the lookup; payments go straight to your wallet. Empty address turns it off.
| Name | Type | Req | Description |
|---|---|---|---|
| address | string | yes | an existing Lightning address of yours (e.g. you@getalby.com), or empty to turn forwarding off |
No output schema declared.
No examples provided.
storage_plan ~22
How long your mail is kept and the prices of longer storage tiers.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
wait_for_code ~141
Block until an email containing a one-time code arrives and return the code. Use the cursor from create_alias as 'after' so a code that arrives quickly is not missed.
| Name | Type | Req | Description |
|---|---|---|---|
| after | string | – | cursor: only mail newer than this message id. Omit to wait for mail arriving after this call |
| from | string | – | sender filter, case-insensitive substring of the From address (e.g. github.com) |
| subject | string | – | subject substring filter |
| timeout_seconds | integer | – | how long to wait (default 120, max 600) |
| to | string | – | recipient filter, e.g. an alias address |
No output schema declared.
No examples provided.
wait_for_email ~130
Block until a matching email arrives (default 120 s) and return it. Filters: from, to, subject.
| Name | Type | Req | Description |
|---|---|---|---|
| after | string | – | cursor: only mail newer than this message id. Omit to wait for mail arriving after this call |
| from | string | – | sender filter, case-insensitive substring of the From address (e.g. github.com) |
| subject | string | – | subject substring filter |
| timeout_seconds | integer | – | how long to wait (default 120, max 600) |
| to | string | – | recipient filter, e.g. an alias address |
No output schema declared.
No examples provided.
wallet_balance ~22
Built-in wallet (optional): collect incoming payments and show the balance.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
wallet_setup ~137
Optional convenience: only if you have NO Lightning wallet. Sets up a small built-in ecash wallet on the same key: your Lightning address becomes <npub>@npub.cash (payments locked to your key at the Minibits Cashu mint). Spending is capped (default 100 sats per payment, 1000 per day). The mint is custodial and in beta: small amounts only. Skip this if you already have a wallet.
| Name | Type | Req | Description |
|---|---|---|---|
| forward_mailbox_addresses | null|boolean | – | also make your mailbox addresses (name@domain) work as Lightning addresses pointing at this wallet, if none is set yet (default true) |
No output schema declared.
No examples provided.
whoami ~24
Your mailbox addresses (created automatically on first use) and whether sending is enabled.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
How do I install the npubmail MCP server?
npubmail ships as an MCPB bundle, a single file you download and open in an MCP host that supports MCPB bundles, such as Claude Desktop. The host reads the launch command from the bundle's own manifest, so there is no command to copy. Before opening it, check the file's SHA-256 matches the one the MCP registry declares for it, 263422516c15da4c6f577cfeb2380ce76242f188ed62e05dfb366229ad892ab9; the commands to do that are on this page. If it does not match, do not open it.
mcpb · npubmail-mcp-0.2.1.mcpb
Download bundleCheck the download matches the SHA-256 the MCP registry declares before you open it. If it does not match, do not open the file.
SHA-256
263422516c15da4c6f577cfeb2380ce76242f188ed62e05dfb366229ad892ab9
macOS / Linux
echo "263422516c15da4c6f577cfeb2380ce76242f188ed62e05dfb366229ad892ab9 npubmail-mcp-0.2.1.mcpb" | shasum -a 256 -c
Windows (PowerShell)
(Get-FileHash -Algorithm SHA256 .\npubmail-mcp-0.2.1.mcpb).Hash -eq "263422516c15da4c6f577cfeb2380ce76242f188ed62e05dfb366229ad892ab9"
Run it in the folder you saved the bundle to, then open the file with an MCPB-capable host such as Claude Desktop.
What is the npubmail MCP server?
npubmail is an MCP server listed in the public MCP registry as com.npubmail/npubmail. Email inbox for AI agents, owned by a Nostr key. No signup or API key. Receive codes, read, send. This page covers its MCPB bundle (https://github.com/obvioussummer46/npubmail/releases/download/v0.2.1/npubmail-mcp-0.2.1.mcpb).
Is the npubmail MCP server safe to use?
npubmail scores 49 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 npubmail MCP server expose?
npubmail exposes 16 tools: buy_storage, create_alias, delete_email, invoice_status, list_emails, and 11 more. Their descriptions and schemas cost roughly 1,265 tokens of context every time the server is loaded.
What licence is the npubmail MCP server under?
npubmail declares the MIT licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.