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Blockscout MCP Server

Official
Exposes Blockscout blockchain data via MCP
How to install ↓ Compare GitHub source repository ↗
Category
Dev Tools #38 of 438
Stars
★ 46 Popular
Transport
Streamable HTTP
Runtime
Hosted (no local runtime) · Python · Docker
Credentials
API key / credential required
License
Other / unspecified
Last commit
Tools
16
66FMRS · C

An official, full-featured multi-chain blockchain data MCP server from Blockscout, offering a hosted endpoint and self-hosting options; requires a PRO API key and targets read-only blockchain queries and analysis.

Strongest · Documentation 18/20 Weakest · Reliability 9/20

Reliability
9/20
Security and permissions
14/20
Maintenance
12/20
Documentation
18/20
Setup experience
13/20
Why each score
Reliability 9/20
The README lists 16 tools with specific parameters and describes a standardized ToolResponse model, cursor pagination, and progress notifications that are broadly consistent with the stated description. However, this review is based only on the README and manifest text provided; no actual CI workflow files or committed test suites were included as verifiable evidence — TESTING.md/API.md/SPEC.md are only referenced, not supplied. Per the static calibration rule, reliability cannot exceed 12 without verifiable execution evidence (real CI plus committed tests covering key paths). Additionally, most data tools depend on a PRO API key and 'fail fast' without one — a controllable failure mode, but it also means large parts of functionality are unverifiable offline, adding uncertainty.
Security and permissions 14/20
The exposed tools are overwhelmingly read-only (balances, contract ABI, transaction info, read_contract, etc.); no send-transaction, payment, or delete-type irreversible-by-default operations are present, so no red-line violation applies. Key handling — acquisition, storage guidance ('never commit... never bake into image'), client-supplied keys via HTTP header, and no silent fallback to the server's own key on a malformed client key — is clearly documented and shows attention to least privilege and key isolation. The optional session-metering feature documents secret generation, persistence, and rotation risk in detail. Telemetry is on by default (tool name, parameters, version, and a SHA-256 fingerprint of the API key) — disclosed transparently with an opt-out, but 'on by default' rather than opt-in is still a minor deduction. The direct_api_call tool also allows GET/POST to a 'raw Blockscout API endpoint,' and the exact scope/restriction of endpoint_path is not fully clarified in the supplied text, leaving some attack-surface ambiguity. Overall, main risks are visible and partly mitigated, but permission boundaries and endpoint scoping are not fully disclosed, so it falls short of a full score.
Maintenance 12/20
A version number of 0.18.1 suggests ongoing iterative releases, and the README references GitHub Releases, a Docker image (ghcr.io), and third-party directory listings (Smithery, Glama), indicating some community activity (44 stars, 12 open issues). However, the repository object metadata reports the license as 'NOASSERTION' while the README claims a custom 'Blockscout Software Licence' with its own LICENSE file — this inconsistency between metadata and documentation is itself a governance gap (the actual terms of the custom license — commercial use, redistribution rights — cannot be confirmed from the material provided). No security-response channel, contribution guidelines, or concrete release history were included as evidence. Maintenance is therefore rated as 'active-looking but with governance/licensing clarity gaps.'
Documentation 18/20
The README is richly layered: detailed setup examples for multiple clients (Claude Desktop via MCPB and Docker proxy, Claude Code, ChatGPT Apps, Codex App/CLI, Cursor), environment variables with defaults and behavior explained, PRO API key acquisition and credit/low-balance warning mechanics, telemetry scope and opt-out instructions, DNS-rebinding protection and tunneling caveats, plus 16 tool descriptions with parameters and multiple example prompts. It also points to supplementary docs (API.md, SPEC.md, AGENTS.md, TESTING.md), indicating a layered documentation structure. Costs and limits (PRO API key requirement, credit metering) are clearly disclosed. Minor deductions are for referenced-but-not-supplied documents (e.g., SPEC.md/TESTING.md content) and incomplete disclosure of some tool boundaries (e.g., direct_api_call's accessible endpoint scope).
Setup experience 13/20
The README provides concrete configuration examples for several mainstream clients (Claude Desktop via MCPB bundle or Docker proxy, Claude Code, ChatGPT Apps marketplace, Codex App/CLI, Cursor), plus local development, Docker build/run, and REST API enablement paths — the steps are clear and actionable. Per the static calibration rule, however, setup cannot score above 15 without verifiable execution evidence (real CI plus committed tests), which was not supplied. Additionally, full functionality requires registering externally for a PRO API key, and the optional session-metering feature involves more complex operational steps (secret generation, persistent volume, TTL configuration), adding overall deployment complexity.

Static review · not runListed 2026-09-07

Read the FMRS scoring method →

Fit and risk

What it can accessUses the network

Best for

  • AI agents and IDE users needing real-time multi-chain blockchain data
  • Blockchain analysts and developers
  • Crypto researchers using Claude, Cursor, ChatGPT, or Codex

Not for

  • Users unwilling to register for a Blockscout PRO API key
  • Scenarios requiring on-chain writes or signing (all tools are read-only queries)
  • Telemetry-sensitive users running community instances without disabling telemetry

Required permissions

  • Requires a Blockscout PRO API key (proapi_ prefix) for data access
  • Accesses https://mcp.blockscout.com/mcp over HTTP transport
  • Self-hosted deployments provide the key via the BLOCKSCOUT_PRO_API_KEY environment variable

Risks and side effects

  • PRO API access is metered in credits; tools append advisory notes when the balance drops below a threshold
  • Community instances collect anonymous telemetry by default (tool names, parameters, version, SHA-256 hash of the API key); disable with BLOCKSCOUT_DISABLE_COMMUNITY_TELEMETRY=true
  • The PRO API key must never be committed to version control or embedded in client-shipped binaries
  • Claude Connectors Directory requires a paid Claude plan and may have restrictions due to a shared access key

Setup

Before you start

Runtime：Hosted (no local runtime) · Python · Docker

BLOCKSCOUT_PRO_API_KEY requiredsecret Blockscout PRO API key obtained from the Blockscout Developer Portal; keys are prefixed with proapi_.
BLOCKSCOUT_SESSION_SECRET optionalsecret Signing secret (at least 32 bytes) for the optional session metering feature.
Other optional settings (13)
BLOCKSCOUT_PRO_API_KEY_HEADER optional Name of the request header carrying a client-supplied key in HTTP mode; defaults to Blockscout-MCP-Pro-Api-Key.
BLOCKSCOUT_PRO_API_LOW_CREDITS_THRESHOLD optional Low-balance advisory threshold in credits (default 5000); set to 0 to disable.
BLOCKSCOUT_PRO_API_KEY_REQUIRED_NOTICE optional Operator-configured notice appended to tool responses lacking a client key; intended for the official public server only.
BLOCKSCOUT_MCP_USER_AGENT optional Custom leading part of the User-Agent header for RPC requests; defaults to 'Blockscout MCP'.
BLOCKSCOUT_DEV_JSON_RESPONSE optional Development toggle returning plain JSON responses instead of SSE streams; for local testing only.
BLOCKSCOUT_MCP_ALLOWED_HOSTS optional Allowed Host list for ngrok tunneling development.
BLOCKSCOUT_MCP_ALLOWED_ORIGINS optional Allowed Origin list for ngrok tunneling development.
BLOCKSCOUT_SESSION_DB_PATH optional Session database path; requires a persistent volume when metering is enabled.
BLOCKSCOUT_SESSION_MCP_MAX_CALLS optional Per-session MCP tool call ceiling for callers without a client key; default 5.
BLOCKSCOUT_SESSION_REST_MAX_CALLS optional Per-session REST call ceiling for callers without a client key; default 5.
BLOCKSCOUT_SESSION_TTL_SECONDS optional Session TTL; default 900 seconds.
BLOCKSCOUT_SESSION_SWEEP_INTERVAL_SECONDS optional How often expired session rows are cleaned up; defaults to once per TTL.
BLOCKSCOUT_DISABLE_COMMUNITY_TELEMETRY optional Set to true to opt out of anonymous usage telemetry.
  1. Register at the Blockscout Developer Portal (dev.blockscout.com) and generate a PRO API key (free tier requires no credit card).
  2. Claude Desktop: download blockscout-mcp.mcpb from GitHub Releases and double-click to install, or configure claude_desktop_config. with docker run sparfenyuk/mcp-proxy.
  3. Claude Code: run claude mcp add --transport http blockscout https://mcp.blockscout.com/mcp --header "Blockscout-MCP-Pro-Api-Key: proapi_your_key_here".
  4. Cursor: add a config with the Blockscout-MCP-Pro-Api-Key header in .cursor/mcp..
  5. Codex: add a Streamable HTTP server with the key header in settings.
  6. Local development: git clone, uv pip install -e ., then run python -m blockscout_mcp_server (stdio) or with --http; Docker image is ghcr.io/blockscout/mcp-server:latest.
claude_desktop_config.json 
{"mcpServers":{"blockscout":{"url":"https://mcp.blockscout.com/mcp","headers":{"Blockscout-MCP-Pro-Api-Key":"proapi_your_key_here"}}}}

Shown for Claude Desktop. Other clients may use a different file or key (VS Code uses "servers") — the configurator below converts it.

.vscode/mcp.json
{
  "servers": {
    "blockscout": {
      "url": "https://mcp.blockscout.com/mcp",
      "headers": {
        "Blockscout-MCP-Pro-Api-Key": "proapi_your_key_here"
      }
    }
  }
}

Goes in your project's .vscode/mcp.json (VS Code uses a "servers" key).

Terminal
claude mcp add --transport http blockscout https://mcp.blockscout.com/mcp --header 'Blockscout-MCP-Pro-Api-Key: proapi_your_key_here'

Run it in a terminal; replace any <…> placeholders with your own values first.

Generate and validate client config

Check that it works

Configure https://mcp.blockscout.com/mcp with the Blockscout-MCP-Pro-Api-Key header in your client; tools such as __unlock_blockchain_analysis__ and get_chains_list should appear in the tool list. Calling get_chains_list confirms the connection works.

Troubleshooting

  1. Verify the PRO API key is supplied via the Blockscout-MCP-Pro-Api-Key header or environment variable
  2. Malformed keys fail any request needing the PRO API with no fallback; no key at all returns a not-configured error
  3. In stdio mode, client keys cannot be sent via headers; set BLOCKSCOUT_PRO_API_KEY yourself
  4. In HTTP mode with Docker, bind --http-host 0.0.0.0 so the server is reachable outside the container
  5. Ngrok tunnels require BLOCKSCOUT_MCP_ALLOWED_HOSTS and BLOCKSCOUT_MCP_ALLOWED_ORIGINS to bypass DNS rebinding protection
  6. Codex CLI requires enabling experimental_use_rmcp_client in config.toml

Things to try

Once connected, you can ask your AI assistant things like:

  • Is any approval set for OP token on Optimism chain by zeaver.eth?
  • Calculate the total gas fees paid on Ethereum by address 0xcafe...cafe in May 2025.
  • Tell me more about the transaction 0xf8a55721f7e2dcf85690aaf81519f7bc820bc58a878fa5f81b12aef5ccda0efb on Redstone rollup.
  • Is there any blacklisting functionality of USDT token on Arbitrum One?

Tools 16

__unlock_blockchain_analysis__ read-only
Initializes a Blockscout MCP session: returns server reference data, the blockscout-analysis skill pointer, and the URI resolution rule. Call once per session before any other tool.
get_chains_list read-only
Returns a list of supported chains, with optional filtering by name, chain ID, native currency, or ecosystem.
get_address_by_ens_name read-only
Converts an ENS domain name to its corresponding Ethereum address.
lookup_token_by_symbol read-only
Searches for token addresses by symbol or name, returning multiple potential matches.
get_contract_abi read-only
Retrieves the ABI (Application Binary Interface) for a smart contract.
inspect_contract_code read-only
Gets the source files of verified contracts.
get_address_info read-only
Gets comprehensive information about an address including balance, ENS association, contract status, token details, and public tags.
get_tokens_by_address read-only
Returns detailed ERC20 token holdings for an address with enriched metadata and market data.
Show 8 more tools
get_block_number read-only
Retrieves the block number and timestamp for a specific date/time or the latest block.
get_transactions_by_address read-only
Gets transactions for an address within a specific time range with optional method filtering.
get_token_transfers_by_address read-only
Returns ERC-20 token transfers for an address within a specific time range.
nft_tokens_by_address read-only
Retrieves NFT tokens owned by an address, grouped by collection.
get_block_info read-only
Returns block information including timestamp, gas used, burnt fees, and transaction count; can optionally include transaction hashes.
get_transaction_info read-only
Gets comprehensive transaction information with decoded input parameters and detailed token transfers.
read_contract read-only
Executes a read-only smart contract function and returns its result. The abi argument is a JSON object describing the function's signature.
direct_api_call read-only
Calls a raw Blockscout API endpoint for advanced or chain-specific data. Supports GET (default) and POST requests with JSON body.

Use cases

Query address balances, token holdings, and NFT collections
Analyze transactions, blocks, and gas fees
Retrieve and inspect ABIs and source code of verified contracts
Execute read-only contract functions via read_contract
Track ERC-20 token transfers within specific time ranges

Supported clients

Claude Desktop
Claude Code
Claude (Web) Connectors Directory
ChatGPT Apps
Codex
Cursor

Listed from the project's documentation, not tested by this site.

Overview

Blockscout MCP Server, maintained by Blockscout, wraps Blockscout APIs and exposes blockchain data—balances, tokens, NFTs, transactions, and contract metadata—via the Model Context Protocol to AI agents and IDEs such as Claude and Cursor. It supports multi-chain access via the Blockscout PRO API with Chainscout metadata enrichment, context optimization, smart response slicing, Base64URL cursor pagination, and a versioned REST API. A Blockscout PRO API key (proapi_ prefix) is required, supplied via the Blockscout-MCP-Pro-Api-Key header or the BLOCKSCOUT_PRO_API_KEY environment variable. The official hosted endpoint is https://mcp.blockscout.com/mcp. Community instances collect anonymous telemetry by default, which can be disabled with BLOCKSCOUT_DISABLE_COMMUNITY_TELEMETRY=true. Licensed under the Blockscout Software Licence.

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Source revision 095ef2c03f1a Data synced 2026-10-19 Read the FMRS scoring method