B20 Check
REMOTE · B20CHECK.COM · 2 COMPONENTS · SCANNED SEP 22
Verify B20 tokens on Base: issuer powers, imposter detection, signed EIP-712 verdicts.
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 Security63
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation not fully verified: no authorisation is required to call this server, and 2 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe. See how to fix → View diagnostics → Unverified
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- The HSTS (Strict-Transport-Security) header is present. View diagnostics → Pass
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability74
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 350 tokens (~175/item across 2 items; 2 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 Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
- Structured output schemas are declared (100% of tools); any adoption earns full credit.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 2 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 3 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
How do I install the B20 Check MCP server?
B20 Check is a hosted endpoint at https://b20check.com/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 · b20check.com
claude mcp add --transport http com-b20check-b20check 'https://b20check.com/mcp'
{
"mcpServers": {
"com-b20check-b20check": {
"url": "https://b20check.com/mcp"
}
}
} {
"servers": {
"com-b20check-b20check": {
"type": "http",
"url": "https://b20check.com/mcp"
}
}
} [mcp_servers.com-b20check-b20check] url = "https://b20check.com/mcp"
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"com-b20check-b20check": {
"type": "remote",
"url": "https://b20check.com/mcp",
"enabled": true
}
}
} openclaw mcp add com-b20check-b20check --url 'https://b20check.com/mcp' --transport streamable-http
mcp_servers:
com-b20check-b20check:
url: "https://b20check.com/mcp" {
"McpServers": {
"com-b20check-b20check": {
"Transport": "http",
"Url": "https://b20check.com/mcp"
}
}
} assistant mcp add com-b20check-b20check -t streamable-http -u 'https://b20check.com/mcp'
{
"mcpServers": {
"com-b20check-b20check": {
"type": "http",
"url": "https://b20check.com/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.
- 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 0
- Stability: 0.97 → pass security
- 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
- 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
- 30 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
- 27 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
- 26 Jul 26 0
First indexed and scored.
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 22 Sept 2026 · Probed https://b20check.com/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=b20check.com | CN=YE2,O=Let's Encrypt,C=US | 9 Sept 2026 | 8 Dec 2026 | ECDSA 256 | ECDSA-SHA384 | 6ef49473f45252b928e79c0d4f10d6e06b7 |
| SANs: b20check.com | ||||||
| CN=YE2,O=Let's Encrypt,C=US (CA) | CN=Root YE,O=ISRG,C=US | 3 Sept 2025 | 2 Sept 2028 | ECDSA 384 | ECDSA-SHA384 | 4df3b15dd6c0784c507cd37b58e6f115 |
| CN=Root YE,O=ISRG,C=US (CA) | CN=ISRG Root X2,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | ECDSA-SHA384 | 872165fc34b6e5fba8add5b3705fb53a |
| CN=ISRG Root X2,O=Internet Security Research Group,C=US (CA) | CN=ISRG Root X1,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | SHA256-RSA | 6c8f1dc727c7117f7baf853ac980f9cd |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of b20check.com. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| com. | present | 19718 | 13 | Verified |
| b20check.com. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
| Header | Value |
|---|---|
| strict-transport-security | max-age=63072000; includeSubDomains |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://b20check.com/mcp | Verified | 200 | |
| http (plaintext) | http://b20check.com/mcp | HTTPS enforced | 301 | https://b20check.com/mcp |
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 →
b20_stats B20 Check usage ~51
Report B20 Check's own live usage: how many B20 tokens are indexed and how many paid calls and unique payers it has served in the last 30 days (from the public Coinbase discovery API).
Input schema present but exposes no named parameters.
| Name | Type | Req | Description |
|---|---|---|---|
| l30DaysTotalCalls | number|null | – | – |
| l30DaysUniquePayers | number|null | – | – |
| lastUpdated | string | – | – |
| snapshotBlock | number | – | – |
| source | string | – | – |
| tokensIndexed | number | – | – |
No examples provided.
verify_b20_token Verify a B20 token ~245
Check whether a token address on Base is a legitimate B20 token and what powers its issuer holds. Call this BEFORE helping the user buy, swap, approve, or move value into any B20 token you have not already verified in this conversation (B20 addresses usually start with 0xb20). Returns a signed verdict: isB20, a verdict of ok/caution/danger/not_applicable, risk flags (mint, freeze, seize, pause, admin, impostor, and more), and the data freshness (indexed/live/not_indexed). not_applicable means the address is not a B20 and not a recognized canonical asset: do NOT read it as safe, there is simply nothing B20-specific to vouch for. Never treat a not_indexed or error result as safe either: a token that cannot be fully checked is never a clean pass. The result carries an EIP-712 signature the user can verify independently; do not overstate it as a guarantee of safety, report what the flags and verdict actually say.
| Name | Type | Req | Description |
|---|---|---|---|
| address | string | yes | The token contract address on Base to check (B20 addresses usually start with 0xb20). |
| Name | Type | Req | Description |
|---|---|---|---|
| address | string | yes | The checked token address (EIP-55). |
| attestation | – | – | Block-pinned EIP-712 attestation; verification recipe at https://b20check.com/v1/schema |
| creation | – | – | – |
| dataSource | string | yes | Data freshness. not_indexed = powers could not be fully checked; never a clean pass. |
| flags | array | yes | Risk flags. Derivation rules: https://b20check.com/methodology |
| isB20 | boolean | yes | True only for a factory-native B20 token. |
| issuerActivity | – | – | – |
| issuerPowers | – | – | mint/burn/pause/freeze/seize/admin powers, latent-inclusive. |
| network | string | – | – |
| variant | – | – | – |
| verdict | string | yes | Roll-up verdict. not_applicable = out of scope, do NOT read as safe. |
No examples provided.
What is the B20 Check MCP server?
B20 Check is an MCP server listed in the public MCP registry as com.b20check/b20check. Verify B20 tokens on Base: issuer powers, imposter detection, signed EIP-712 verdicts. This page covers its hosted endpoint (https://b20check.com/mcp).
Is the B20 Check MCP server safe to use?
B20 Check scores 81 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 B20 Check MCP server expose?
B20 Check exposes 2 tools: verify_b20_token, b20_stats. Their descriptions and schemas cost roughly 296 tokens of context every time the server is loaded.
Does the B20 Check MCP server require authentication?
No. We connected to B20 Check without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the B20 Check MCP server still maintained?
B20 Check is still listed as active in the MCP registry. We last reached this channel on 22 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.