Debugging BlockRun MCP

SkillMedia

Use when the BlockRun MCP server (@blockrun/mcp) is installed but misbehaving — 'Failed to connect', spawn npx ENOENT, blockrun missing from claude mcp list, HTTP 402 / Insufficient balance, fetch failed, video or music timeouts, a 501 'not served' error or 'API error after payment' while the balance never moved, spend-confirmation dialogs not appearing, or a Polymarket buy/redeem failing after funding. Symptom → cause → fix, plus what never to do.

Available today. Use it from your connected AI after setup.

Connect ahel once, and every AI you use reads what you have installed.

Then ask your AI: use the Debugging BlockRun MCP skill

What this skill tells your AI

The instructions your AI receives, as published by blockrunai/blockrun-mcp in skills/blockrun-debug/SKILL.md and read by ahel’s review.

Find the row, run the fix, stop. Most "broken" reports are one of the first three rows.

Rules before touching anything

  1. A 402 / "Insufficient balance" is a funding state, not a bug. Call blockrun_wallet first. Never retry the failing tool in a loop — it will 402 identically every time and the failed attempts cost nothing, but they burn turns.
  2. Never delete or regenerate ~/.blockrun/.session. It is the only copy of the key that holds the user's USDC and their Polymarket deposit wallet. There is no recovery.
  3. Never advise withdrawing from Polymarket to "start over". Every post-funding trade failure seen so far was a missing approval; a withdraw does not fix it and costs a round trip.
  4. Reproduce with the free call blockrun_wallet before anything paid.

Run these first (read-only, 10 seconds)

node -v && which npx                     # runtime present, ≥ 20.19?
claude mcp get blockrun                  # registered command, env, AND scope (-s user / project / local)
npx -y @blockrun/mcp@latest --version    # does the package itself run? (prints e.g. 0.43.0)

Use the scope claude mcp get reports in every remove/add below — the examples say -s user because that is the documented install, but a project-scoped install re-added at user scope leaves a duplicate. Then, in the session: blockrun_wallet (free) → blockrun_models (free) → the tool that failed, once.

Symptom → cause → fix

SymptomCauseFix
claude mcp listblockrun … ✗ Failed to connect, or logs show spawn npx ENOENTThe client's launcher can't find node/npx — nvm, Homebrew, fnm, volta. Interactive shell has them; the spawner does not.claude mcp remove blockrun -s user then claude mcp add blockrun -s user -e PATH="$PATH" -- npx -y @blockrun/mcp@latest. Quit and relaunch the client. Codex: codex mcp add blockrun --env PATH="$PATH" -- …. JSON clients (Claude Desktop / Cursor / Windsurf): set "command" to the output of which npx; file paths are in the blockrun-setup skill.
blockrun absent from claude mcp listWrong scope, or Node < 20.19, or a corrupt npx cachenode -v (≥ 20.19). claude mcp get blockrun. rm -rf ~/.npm/_npx. Re-run the install line.
Connects, but every paid tool → HTTP 402 / Insufficient balanceWallet is empty (or on the wrong chain for this tool)blockrun_wallet → read balance + chain. blockrun_wallet action:"setup" → address + QR. Fund with USDC on Base (or switch to Solana). Then retry once.
402 although balance shows fundsChain mismatch: a Base-only tool (defi, modal, native claude-* chat) while active chain is Solana. Everything else — music, speech, RealFace, price, media — now pays on either chain.The error names it. blockrun_wallet action:"chain" chain:"base".
402 from api.blockrun.aiNot a wallet problem: the server is on an API key and the ACCOUNT is out of credit.Top up at https://user.blockrun.ai/dashboard/credits. Do not look for a wallet.
401 from api.blockrun.aiBLOCKRUN_API_KEY rejected.Check the key at https://user.blockrun.ai/dashboard/keys.
"needs wallet mode" on Polymarket / wallet / realface listKeypair-only capability while BLOCKRUN_API_KEY is set.Unset BLOCKRUN_API_KEY and restart to use a wallet.
Startup error "not a valid BlockRun API key"BLOCKRUN_API_KEY is malformed. It deliberately fails loudly rather than silently spending USDC from a wallet instead.Fix the value or unset it.
Grok (or any client with a startup timeout) shows blockrun [unavailable], and mcp doctor says server timed out (no response within 30s)NOT broken: a cold npx -y is still downloading the package and its dependency tree when the client gives up. Grok's startup_timeout_sec defaults to 30; the cold start measured 17s on a fast connection and 42-46s on a slower box. Nothing is charged — the server never started.Raise it in ~/.grok/config.toml ([mcp_servers.blockrun]startup_timeout_sec = 120), or npm install -g @blockrun/mcp@latest and point the client at blockrun-mcp. Confirm the package itself is fine first: npx -y @blockrun/mcp@latest in a terminal answers an initialize line. Only the first run is slow — npx caches by exact spec.
fetch failed / balance-check timeoutBase RPC blip; the tool rotates through 3 public RPCsWait 30 s, retry once. Persistent → a local proxy/firewall is blocking outbound RPC.
Video/Music generation timed outUpstream queue. Not charged — payment settles on completion only.Retry, or pick a faster model. Do not retry-loop; jobs take 60–180 s.
blockrun_price with category:"stocks" / "usstock"Equity quotes are not served (gateway 501 …)The gateway withdrew equity price/history on 2026-09-05 (licensing), and the tool answers before the wallet is consulted. Not an outage. Not charged.Do not retry. action:"list" category:"stocks" market:"us" still returns the ticker catalog for free. Equity coverage: hello@blockrun.ai.
blockrun_markets on sports/*Predexon's sports/* routes have returned an upstream 500 … since 2026-08-04 (builds before 0.49.0: API error after payment: 502 / Request failed with no balance change)Upstream Predexon outage since 2026-08-04. The gateway releases the payment on the upstream 500, so the old wording asserted a charge that never happened. Not charged when the response carries the gateway's (payment NOT charged) confirmation — the error then says so; without it the error tells you to check blockrun_wallet action:"report".Use path:"markets/search" with params:{ q:"NBA" } or polymarket/events with params:{ search:"NBA" }. Not markets + league — removed upstream 2026-08-04, 404s before payment. Do not retry sports/*. Upgrade to ≥ 0.49.0 so the error says this itself.
A config names blockrun_surf → the client reports an unknown toolThe tool was REMOVED in 0.49.0: the gateway has answered every Surf path with 410 endpoint_retired since 2026-09-06, so it could only ever error. Nothing is charged.Use blockrun_price / blockrun_dex / blockrun_defi / blockrun_markets / blockrun_rpc; the surf skill maps each former endpoint. Drop blockrun_surf from any allowlist.
blockrun_video / blockrun_imageThe gateway quoted $X for <model>, but this tool expected about $Y (N.Nx the published rate) … Refusing to sign it — no charge was madeThe 402 price is far above the published rate: the gateway repriced the model, or a lagging deployment substituted another one. Live 2026-09-08: sol.blockrun.ai does not know azure/sora-2 and quotes Seedance 2.0 Pro at $1.135 in its place. Not charged — the tool refuses before signing.For Sora: blockrun_wallet action:"chain" chain:"base". Otherwise pick another model or chain, and report the quote (the message names what the gateway labelled it) so the estimator or the gateway gets fixed.
Any tool → The gateway does not serve this endpoint (501 Not Implemented)The route is withdrawn, not down. Before payment the message ends "nothing was charged"; after payment it tells you to check the ledger instead, because the formatter cannot know whether the nonce was released.Do not retry. blockrun_wallet action:"report" shows whether the call settled.
Model id 404sDelisted upstreamblockrun_models for the live list.
Startup prints 🚨 WALLET PRIVATE KEY DETECTED IN CONFIG FILEA raw key sits somewhere it was never meant to be — a header, an args entry, the old hosted-auth field — in a client config file (~/.claude.json, Claude Desktop, Cursor, Windsurf). Since 0.49.0 the DOCUMENTED override mcpServers.*.env.BLOCKRUN_WALLET_KEY / SOLANA_WALLET_KEY does NOT trigger this banner; it gets a short plaintext-and-synced note instead.Banner: treat the key as compromised — move funds to a new wallet, remove it from the config. Note: optional; prefer ~/.blockrun/.session or BLOCKRUN_KEYCHAIN=auto.
No spend-confirmation dialog with BLOCKRUN_CONFIRM_SPEND=onClient doesn't support MCP elicitation (Windsurf, Codex, Gemini CLI) — the server proceeds without asking, by designUse BLOCKRUN_BUDGET_LIMIT / blockrun_wallet action:"delegate" as the guard, or use Claude Code / Cursor / VS Code where the dialog renders.
Dialog appears, user clicks OK, tool says "declined"Only an explicit Decline stops a charge; Cancel/ESC proceeds. If it says declined, Decline was pressed.Re-run the call; approve it.
Update available: vX → vY on stderrInformationalSwitch to the blockrun-upgrade skill.

Polymarket (blockrun_polymarket)

SymptomCauseFix
Funded the deposit wallet, buy fails with insufficient allowance / neg-risk market rejectsThe one-time gasless approval batch hasn't run, or predates an upgrade that added the NegRisk-adapter and collateral-adapter grantsblockrun_polymarket action:"setup" confirm:true once (idempotent, gasless, signs approvals — tell the user before running). Wait for it to report ready. Retry the buy. Do not withdraw. Still failing → check the signer row below: the funded wallet and the signing wallet must be the same address.
redeem reverts or redeems 0Same missing approvals (collateral adapter)Same fix: setup confirm:true, then redeem again.
Order rejected by regionOrder placement is geoblocked by IP. The MCP routes CLOB traffic via BlockRun's Finland egress by default.Check POLYMARKET_CLOB_HOST was not overridden. setup prints the region status.
setup shows a different signer address than expectedSigner precedence: BLOCKRUN_WALLET_KEY env → agent wallet.json~/.blockrun/.sessionUnset the override, or fund the address setup actually prints.

The full walkthrough is docs/polymarket-trading-setup.md in the package repo.

Why "retried 5 times" happens and how to stop it

A 402 is free — nothing settles — so a retry loop costs turns, not money, and no budget cap will interrupt it. The stop is behavioural: the README's "For agents" block and the blockrun skill both say call blockrun_wallet first, never retry a 402 blindly. If a client keeps looping, install the skills so that rule is in context (npx -y @blockrun/mcp@latest skills install).

Red flags — stop

  • You are about to retry a 402 a second time without checking the wallet.
  • You are about to rm anything under ~/.blockrun/.
  • You are about to suggest a Polymarket withdraw to fix a failed order.
  • You are about to test with blockrun_video or blockrun_phone — $0.30+/s and $5 numbers.

Signals

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Last commit
Sep 2026

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