Bellwether
REMOTE · API.BELLWETHER.MARKETS · SCANNED SEP 26
Live Kalshi + Polymarket prediction-market data and cross-venue arbitrage spreads, one schema.
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 Security57
- 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 3 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
- 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
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability57
- AI-judged instruction clarity (fair).Partial
- Tool/resource definitions use about 114 tokens (~38/item across 3 items; 3 tools + 0 resources), lean.Pass
- 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 Coverage71
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 0% of tool parameters carry a description.Fail
- Structured output schemas are declared (67% 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 3 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 Bellwether MCP server?
Bellwether is a hosted endpoint at https://api.bellwether.markets/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 · api.bellwether.markets
claude mcp add --transport http markets-bellwether-prediction-markets 'https://api.bellwether.markets/mcp'
{
"mcpServers": {
"markets-bellwether-prediction-markets": {
"url": "https://api.bellwether.markets/mcp"
}
}
} {
"servers": {
"markets-bellwether-prediction-markets": {
"type": "http",
"url": "https://api.bellwether.markets/mcp"
}
}
} [mcp_servers.markets-bellwether-prediction-markets] url = "https://api.bellwether.markets/mcp"
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"markets-bellwether-prediction-markets": {
"type": "remote",
"url": "https://api.bellwether.markets/mcp",
"enabled": true
}
}
} openclaw mcp add markets-bellwether-prediction-markets --url 'https://api.bellwether.markets/mcp' --transport streamable-http
mcp_servers:
markets-bellwether-prediction-markets:
url: "https://api.bellwether.markets/mcp" {
"McpServers": {
"markets-bellwether-prediction-markets": {
"Transport": "http",
"Url": "https://api.bellwether.markets/mcp"
}
}
} assistant mcp add markets-bellwether-prediction-markets -t streamable-http -u 'https://api.bellwether.markets/mcp'
{
"mcpServers": {
"markets-bellwether-prediction-markets": {
"type": "http",
"url": "https://api.bellwether.markets/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.
- 25 Sept 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 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
- 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
- 7 Aug 26 0
- The server no longer declares the “experimental” capability 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
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 26 Sept 2026 · Probed https://api.bellwether.markets/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=api.bellwether.markets | CN=YE1,O=Let's Encrypt,C=US | 31 Aug 2026 | 29 Nov 2026 | ECDSA 256 | ECDSA-SHA384 | 6dba5f71aaad10d10199dac813776cbc3c5 |
| SANs: api.bellwether.markets | ||||||
| CN=YE1,O=Let's Encrypt,C=US (CA) | CN=Root YE,O=ISRG,C=US | 3 Sept 2025 | 2 Sept 2028 | ECDSA 384 | ECDSA-SHA384 | 5ddd70dd31f801c85c186a7a04b80afe |
| 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 api.bellwether.markets. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| markets. | present | 58144 | 8 | Verified |
| bellwether.markets. | 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 |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://api.bellwether.markets/mcp | Verified | 200 | |
| http (plaintext) | http://api.bellwether.markets/mcp | HTTPS enforced | 308 | https://api.bellwether.markets/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 →
get_market ~40
Get one normalized market. venue is 'kalshi' or 'polymarket'.
| Name | Type | Req | Description |
|---|---|---|---|
| market_id | string | yes | – |
| venue | string | yes | – |
No output schema declared.
No examples provided.
list_markets ~35
List open prediction markets across Kalshi and Polymarket (normalized).
| Name | Type | Req | Description |
|---|---|---|---|
| limit | integer | – | – |
| venue | – | – | – |
| Name | Type | Req | Description |
|---|---|---|---|
| result | array | yes | – |
No examples provided.
matching_markets ~39
Find the same real-world event on both venues, with the YES price spread.
| Name | Type | Req | Description |
|---|---|---|---|
| limit | integer | – | – |
| threshold | number | – | – |
| Name | Type | Req | Description |
|---|---|---|---|
| result | array | yes | – |
No examples provided.
What is the Bellwether MCP server?
Bellwether is an MCP server listed in the public MCP registry as markets.bellwether/prediction-markets. Live Kalshi + Polymarket prediction-market data and cross-venue arbitrage spreads, one schema. This page covers its hosted endpoint (https://api.bellwether.markets/mcp).
Is the Bellwether MCP server safe to use?
Bellwether scores 73 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 Bellwether MCP server expose?
Bellwether exposes 3 tools: list_markets, get_market, matching_markets. Their descriptions and schemas cost roughly 114 tokens of context every time the server is loaded.
Does the Bellwether MCP server require authentication?
No. We connected to Bellwether without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the Bellwether MCP server still maintained?
Bellwether is still listed as active in the MCP registry. We last reached this channel on 26 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.