# Falcon Shield (remote · falcon-shield.falcon-sol.workers.dev)

Pre-sign Solana tx guard for agents: ALLOW/WARN/BLOCK verdict, x402 USDC pay-per-call.

- Trust score: 60/100 (medium)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-04

## Components

- remote · `falcon-shield.falcon-sol.workers.dev`: 60/100 (this document), [markdown](https://verifymcp.io/servers/ygfalcon-falcon-shield/falcon-shield.md), [page](https://verifymcp.io/servers/ygfalcon-falcon-shield/falcon-shield)

## Channel facts

- Endpoint: `https://falcon-shield.falcon-sol.workers.dev/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.0.0`

## Trust breakdown

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. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-11-04.

- **Endpoint Security**: 46/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 1 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - HTTPS enforcement could not be verified: the plaintext port answered with HTTP 405, which proves neither a plaintext path nor enforcement.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 64/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 453 tokens (~453/item across 1 items; 1 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 17/100
  - Stability observed for 5 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 1 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 1 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### How do I install the Falcon Shield MCP server?

Falcon Shield is a hosted endpoint at https://falcon-shield.falcon-sol.workers.dev/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.

### Claude

```bash
claude mcp add --transport http ygfalcon-falcon-shield 'https://falcon-shield.falcon-sol.workers.dev/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "ygfalcon-falcon-shield": {
      "url": "https://falcon-shield.falcon-sol.workers.dev/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "ygfalcon-falcon-shield": {
      "type": "http",
      "url": "https://falcon-shield.falcon-sol.workers.dev/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.ygfalcon-falcon-shield]
url = "https://falcon-shield.falcon-sol.workers.dev/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "ygfalcon-falcon-shield": {
      "type": "remote",
      "url": "https://falcon-shield.falcon-sol.workers.dev/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add ygfalcon-falcon-shield --url 'https://falcon-shield.falcon-sol.workers.dev/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  ygfalcon-falcon-shield:
    url: "https://falcon-shield.falcon-sol.workers.dev/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "ygfalcon-falcon-shield": {
      "Transport": "http",
      "Url": "https://falcon-shield.falcon-sol.workers.dev/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add ygfalcon-falcon-shield -t streamable-http -u 'https://falcon-shield.falcon-sol.workers.dev/mcp'
```

### Other

```json
{
  "mcpServers": {
    "ygfalcon-falcon-shield": {
      "type": "http",
      "url": "https://falcon-shield.falcon-sol.workers.dev/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-11-03 (score 60, +1)

No change was recorded against any check on this day. Stability & Change Management went from 10 to 13. That category is still filling its 30-day observation window: 3 days of observed history at the previous scan, 4 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-11-01 (score 59, +1)

No change was recorded against any check on this day. Stability & Change Management went from 3 to 7. That category is still filling its 30-day observation window: 1 days of observed history at the previous scan, 2 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-31 (score 58, 0)

- [functional regression] Schema quality: 403 → 453
- [functional improvement] Stability: unverified → 0.03
- [cosmetic] “shield_guard_check” reworded the description of “simulate”

### 2026-10-30 (score 58)

First indexed and scored.

## MCP tools (1)

### `shield_guard_check` (~453 tokens)

Falcon Shield: check a Solana tx before signing

Use this before an agent or wallet signs a Solana transaction. Decodes the unsigned or signed transaction and returns NO_MATCH (no known-bad pattern matched; not a safety guarantee), WARN, or BLOCK, with plain-language reasons and a signed receipt. Pass an x402 quote to also check a payment transaction against it (overpay, approve-instead-of-transfer, unchecked Transfer, wrong payee). Errors return ERROR and are never charged. Price $0.009 USDC (x402, Solana).

Input parameters:

- `cap_base_units` (integer): Hard per-payment cap enforced even if the quote asks for more.
- `caps` (object): Optional spend caps you declare; any violation returns BLOCK. Keys: max_amount (int base units per outflow), max_amounts ({mint|'SOL': int}), max_total (int per asset), allowed_payees ([pubkey]; owne…
- `known_addresses` (array): Optional: pubkeys you have recently paid or received from. A recipient that only looks like one of these (same first/last characters) is flagged as address poisoning.
- `quote` (object): x402 quote the tx pays: {asset, amount, pay_to | pay_to_token_account, decimals?, token_program?}.
- `simulate` (boolean): Simulate against Solana mainnet (Helius RPC, sigVerify off, recent blockhash replaced, never submitted). Default true; false = static checks only. If simulation fails the verdict is at least WARN, ex…
- `strict` (boolean): Escalate HIGH-risk token approvals (unlimited or third-party delegate) from WARN to BLOCK. Default false.
- `tx` (string, required): Base64 wire transaction (also accepts an RPC getTransaction result).
- `wallet` (string): Your own pubkey; only this key is treated as 'you'.

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/ygfalcon-falcon-shield/falcon-shield#diagnostics

## Score history

- 2026-11-04: 60
- 2026-11-03: 60
- 2026-11-02: 59
- 2026-11-01: 59
- 2026-10-31: 58
- 2026-10-30: 58

## Common questions

### What is the Falcon Shield MCP server?

Falcon Shield is an MCP server listed in the public MCP registry as io.github.ygfalcon/falcon-shield. Pre-sign Solana tx guard for agents: ALLOW/WARN/BLOCK verdict, x402 USDC pay-per-call. This page covers its hosted endpoint (https://falcon-shield.falcon-sol.workers.dev/mcp).

### Is the Falcon Shield MCP server safe to use?

Falcon Shield scores 60 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 Falcon Shield MCP server expose?

Falcon Shield exposes 1 tool: shield_guard_check. Their descriptions and schemas cost roughly 453 tokens of context every time the server is loaded.

### Does the Falcon Shield MCP server require authentication?

No. We connected to Falcon Shield without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the Falcon Shield MCP server still maintained?

Falcon Shield is still listed as active in the MCP registry. We last reached this channel on 4 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://falcon-shield.falcon-sol.workers.dev/mcp
- Website: https://x.com/ygfalcon
- Changelog RSS feed: https://verifymcp.io/servers/ygfalcon-falcon-shield/falcon-shield.xml
- Changelog JSON feed: https://verifymcp.io/servers/ygfalcon-falcon-shield/falcon-shield.json
- HTML version of this page: https://verifymcp.io/servers/ygfalcon-falcon-shield/falcon-shield