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LEGION Verify: MCP tool-list history

Official registry Security

Check if an MCP server changed its tools: signed history, per-server coverage, offline proofs.

Source code Website Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

Remote (streamable-http)
Claude Code 
claude mcp add --transport http legion-verify-mcp-tool-list-history 'https://mcp.legion-api.com/mcp'
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "legion-verify-mcp-tool-list-history": {
            "type": "http",
            "url": "https://mcp.legion-api.com/mcp"
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. LEGION Verify — MCP server to detect MCP tool drift (5 read-only tools) · v1.3.0
  2. Tools — all read-only (readOnlyHint: true, destructiveHint: false)
  3. Connect
  4. Try it
  5. Verify the whole log yourself (no MCP, no pip)
  6. Limits

LEGION Verify — MCP server to detect MCP tool drift (5 read-only tools) · v1.3.0

Did an MCP server change its tools after you approved them? A model reads tool descriptions as instructions, so a silent change to a description or an inputSchema (tool drift, "rug pull") matters. LEGION Verify answers from LEGION's signed, append-only transparency log of MCP tool lists: what a server exposed, and when it changed. Every answer is checked against a keyring anchored on a pinned root key fingerprint (Ed25519, RFC 9162 Merkle proofs); evidence bundles can be re-checked offline.

To pin tool lists in a lockfile and fail CI on drift, see legion-lock.

Tools — all read-only (readOnlyHint: true, destructiveHint: false)

ToolWhat it doesNetwork
get_checkpointLatest signed tree head; signature checked against the keyringGET fixed routes of https://tlog.legion-api.com/tlog/v0
get_server_changesSigned tool-list history of one MCP server (registry id, limit 1–50), newest first, plus an evidence bundle for the latest recordGET fixed routes of https://tlog.legion-api.com/tlog/v0
verify_evidence_bundleVerifies a bundle OFFLINE: keyring chain from the pinned root, record signature, signed head, RFC 9162 inclusion proof; optional check against a tools hash you approved (MATCHES_APPROVED / UNAPPROVED_CHANGE)none
verify_mcp_serverPaste an MCP server URL: matched against the public MCP registry, then the latest signed tool-list record, change count (total / 30 days), RFC 9162 inclusion proof re-checked from the pinned root, and an evidence bundle. live=true adds the tool list served now, compared with the signed one (not signed)GET https://legion-api.com/drift/verify (default; LEGION_DRIFT_BASE). The live comparison runs only on the hosted endpoint, and only for servers listed in the registry
check_mcp_serverOne call for a registry id: signed tool-list fingerprint history, last change with fingerprints before/after and diff link, per-server coverage from the signed COVERAGE_V1 register (full_register is COMPLETE only if observed in every cycle, UNKNOWN if partial), proof URLs, and one command that re-checks everything offline (legion_check kit). Unknown id → UNKNOWN (absence from the log is not a verdict)GET fixed routes of https://tlog.legion-api.com/tlog/v0 and https://legion-api.com/tlog/v0/coverage

Nothing else: no write, no purchase, no private key, no API key needed. The only caller-supplied URL is the one given to verify_mcp_server: it is looked up in the registry; this server never connects to it. On the hosted endpoint, live=true lets LEGION's drift service send initialize + tools/list to that server, and only if it is a registry entry with a public address.

Connect

Claude Code (remote)

claude mcp add --transport http legion-verify https://mcp.legion-api.com/mcp

Claude Desktop (local, stdio) — claude_desktop_config.json:

{ "mcpServers": { "legion-verify": { "command": "python3", "args": ["/ABSOLUTE/PATH/server.py"] } } }

(requires pip install "mcp==2.1.1"; server.py and legion_tlog_verify.py in the same folder)

Any MCP client (remote): streamable HTTP at https://mcp.legion-api.com/mcp, no auth.

Try it

  1. "Call get_checkpoint and give tree_size, root_sha256 and signature_valid."
  2. "With get_server_changes, show the signed history of xyz.signomy/civitae (limit 3)."
  3. "Pass the evidence_bundle you got to verify_evidence_bundle and tell me whether the proof is valid."
  4. "Use verify_mcp_server on https://tandem.ac/mcp with live=true: did its tools change since the signed record?"

Same check in a browser, with an embeddable badge: https://legion-api.com/drift/check/

Verify the whole log yourself (no MCP, no pip)

PIN=a7c6a35b1c2c81d589a30c2ad628679bdea9da4139d49aa3c42cdde6e1c65036 curl -fsSLO https://legion33shadow.github.io/legion-tlog-mirror/legion_verify_mirror.py python3 -I -S legion_verify_mirror.py "$PIN"

Root key fingerprint — pin it out of band: a7c6a35b1c2c81d589a30c2ad628679bdea9da4139d49aa3c42cdde6e1c65036

Limits

The log is the signed record of one observer (LEGION); it does not show what a server serves to other clients. Only name, description and inputSchema are fingerprinted. A change appears only after the next LEGION observation and the next signed head. Bitcoin anchors are pending (no ots verify on a full node yet). No independent witness has cosigned yet. Servers that require auth are not observed.

Public server (v1.3.0): immutable proofs and per-head history are cached; each client (IP seen by Cloudflare) may trigger at most 20 uncached log requests per minute (CLIENT_RATE_LIMITED otherwise; cached answers still served).

License: MIT (see LICENSE).

Frequently asked questions

What is LEGION Verify: MCP tool-list history?

Check if an MCP server changed its tools: signed history, per-server coverage, offline proofs.

How do I install LEGION Verify: MCP tool-list history?

It runs as a remote server. In Claude Code: claude mcp add --transport http legion-verify-mcp-tool-list-history 'https://mcp.legion-api.com/mcp'. For other clients, paste the JSON configuration from this page into their MCP settings.

Does LEGION Verify: MCP tool-list history need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is LEGION Verify: MCP tool-list history open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains LEGION Verify: MCP tool-list history?

It is published by Legion33shadow. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.