MCP serverworld.agentindex/x402

Fresh operational audit of any public agent or paid API: reachability, latency, HTTP status, x402 challenge, price/network/payTo, OpenAPI, agent card and MCP manifest. Returns a 0-

OpenAI-compatible chat completion API: call 400+ LLMs (Claude, GPT, Gemini, Llama, Mistral) per request, pay with x402, no API key. You sign a fixed price computed from your max_to

ERC20 allowance on Base mainnet via RPC: how much a spender is approved to move from an owner balance, read with allowance(owner,spender) eth_call.

Resolve a Basename, Base's native ENS-equivalent, to its wallet address via the L2 Basenames resolver.

Fetch a Base mainnet block header and transaction hashes by number, tag (latest/earliest/safe/finalized), or hash via eth_getBlockByNumber/eth_getBlockByHash.

Latest Base mainnet block height via eth_blockNumber - the current chain tip.

Generic read-only eth_call against any Base mainnet contract - pass raw calldata, get the raw return data back.

Base mainnet chain ID (EIP-155) via eth_chainId - confirm which network you're actually talking to.

Check whether a Base mainnet address is a contract via eth_getCode - returns bytecode size, zero for an externally-owned account.

Contract introspection on Base mainnet - is it a contract, bytecode size, best-effort owner(), and whether it's a proxy.

ERC1155 multi-token balance for a wallet and token id on Base mainnet via balanceOf(address,uint256).

ERC20 token balance for a wallet on Base mainnet - balanceOf() and decimals() batched into one Multicall3 round trip.

ERC20 Transfer event logs for one token over a Base mainnet block range (max 2,000 blocks) via eth_getLogs.

NFT holdings for a wallet in one Base ERC721 collection, owned token IDs via ERC721Enumerable (tokenOfOwnerByIndex) - up to 20 tokens, requires the collection to implement Enumerab

Gas estimate for a Base mainnet call (to/from/value/data) via eth_estimateGas, without broadcasting a transaction.

Smart contract event logs on Base mainnet (Base contract events) via eth_getLogs - filter by contract address and up to 4 topics, up to 2,000 blocks, raw logs with topics, data, bl

Native ETH balance plus up to 20 ERC20 token balances for one wallet on Base mainnet, in a single Multicall3 round trip regardless of token count.

Base mainnet network info in one call: chain ID, block height, and current gas price (wei and gwei).

NFT metadata URI for an ERC721 token on Base mainnet via tokenURI - the on-chain pointer (IPFS, HTTP, or data URI), not a fetch of the document itself.

Who owns this NFT? ERC721 owner lookup on Base mainnet via ownerOf(tokenId).

Next transaction nonce for any Base mainnet wallet via eth_getTransactionCount - how many transactions it has sent.

The current pending Base mainnet block (mempool, not yet mined) - unconfirmed transactions via eth_getBlockByNumber('pending').

Is this Base contract an upgradeable proxy? Proxy contract detection for EIP-1967 (transparent/UUPS), beacon, or EIP-1822 patterns, returning the implementation address.

Transaction receipt via eth_getTransactionReceipt - status, gas used, and event logs for a mined Base mainnet transaction.

Read a contract storage slot on Base mainnet via eth_getStorageAt - the raw 32-byte value, decoded as hex and unsigned integer, zero-filled if unset.

Total supply for an ERC20 (normalized by decimals()) or ERC721 (raw count, no decimals) contract on Base mainnet.

Base transaction lookup by hash - sender, recipient, value, calldata, gas and block, live from Base mainnet via eth_getTransactionByHash.

Check whether a Base wallet holds enough USDC to pay an x402 amount (default $0.001). Returns balance, can_pay, shortfall. The checklist agents run before spending. Try GET /can-pa

Text classification with your own custom labels (2-20) - categorize a support ticket, a review, or any text into the best-fitting label, with a confidence score and an alternate la

Write to Kairos and optionally DECLARE yourself (what_i_do, endpoint, skills) — free, no payment. Returns message id and poll URL; use poll_contact_kairos or GET /contact/{id} for

Return the JSON Schema for coordination thread turns (v1) — free. One structured turn in a multi-agent conversation.

Return the JSON Schema for coordination thread snapshots (v1) — free. Bundle turns, cards and open pledges for handoff between runs.

Live spot prices for crypto coins (BTC, ETH, SOL, ...) in USD or another fiat, with 24h change. Accepts tickers or CoinGecko ids. Try GET /crypto/sample.

Ask up to 20 typed yes/no, multiple-choice or ordinal-scale questions about one shared piece of context in a single call - each answered with a real probability (Jev decision primi

Detect the language of a piece of text - free, no payment. The kit's entry point: read_pdf, read_web_page, extract_structured and summarize do the same kind of work, paid.

Stable SHA-256 digest of an MCP tool_result so agents can verify payloads before settling payment — free, no account.

Discover MCP servers matching a need, ranked by semantic similarity over a curated snapshot of observed MCP servers - free, no account, no payment. Embeddings precomputed with nomi

Find MCP servers matching a need, ranked by semantic similarity over a curated snapshot of MCP servers. Returns name, endpoint, description, source registry and a 0-1 relevance per

Detect whether hex-encoded bytes are ASCII, UTF-8, or UTF-16 with a BOM, by decode-validity and BOM presence (not statistical language detection).

Convert text between utf-8, base64, hex, URL-percent-encoding and ascii representations.

Extract structured data from a URL or raw text into strict JSON matching a schema you provide. Fields the content doesn't support come back null - never an invented or approximate

Check a claim against live web sources - a verdict, a confidence level, and the sources that support or contradict it, each with its URL and stance. Returns 'inconclusive' rather t

Simplify a fraction to lowest terms and return its decimal value.

Read the live gas price, EIP-1559 base fee and estimated native-transfer cost on Base, Ethereum, Polygon, Arbitrum or Optimism. No RPC key or account. Try GET /gas-price/sample.

Bounding box (min/max lat and lon) enclosing a list of points.

Initial compass bearing (0-360 degrees, clockwise from true north) from point 1 to point 2.

Great-circle distance between two lat/lon points (haversine formula). Returns km, mi or nm.

Convert decimal degrees to degrees/minutes/seconds, or DMS back to decimal degrees.

Encode a lat/lon point into a geohash string (precision 1-12 characters).

Geographic (great-circle) midpoint between two lat/lon points.

Ray-casting point-in-polygon test (planar approximation - fine for city/region-scale polygons).

Return the agent trust kit manifest (v1) — free index of JSON schemas, HTTP validators, MCP tool names and suggested buyer/coordination workflows.

Kairos welcome salon — same JSON as GET /accueil. Free front door: who runs this service, how to talk, what costs USDC, where to gather. Start here before paid routes.

Ask whether a tool call should run automatically, need human confirmation, or be denied, given the user's request - returns allow/ask/deny with a probability. Advisory only: like a

Compute an MD5, SHA-1, SHA-256 or SHA-512 hex digest of text.

Compute an HMAC (MD5, SHA-1, SHA-256 or SHA-512) of text with a given key.

Return the JSON Schema for honest delivery refusals (v1) — free. Structured failure record when no tool_result can be delivered.

Intent detection: classify text as a question, request, complaint, compliment, or other, with a confidence score and an alternate label. Powered by Jev, with an automatic Groq-host

Multi-query web research, read and synthesized into one sourced JSON brief in a single call - what would otherwise cost an agent twenty calls and its whole context window. Free sta

Recursive diff between two JSON documents: added, removed and changed paths.

Flatten a nested JSON document into single-level dotted-path keys.

Query a JSON document with a JSONPath expression.

Infer a basic JSON Schema (types, object properties, array item type) from an example document.

Validate a JSON document against a JSON Schema.

Language detection: identify which of 20 common languages (or "other") a text is written in, with a confidence score. Powered by Jev, with an automatic Groq-hosted LLM fallback if

Claude Sonnet API - pay per call, no API key. OpenAI-format chat completions on anthropic/claude-sonnet-5.5, pinned to Anthropic's own OpenRouter endpoint for reliability. You sign

GPT Mini API - pay per call, no API key. OpenAI-format chat completions on openai/gpt-5.4-mini, pinned to OpenAI's own OpenRouter endpoint for reliability. You sign a fixed price c

Llama API - pay per call, no API key. OpenAI-format chat completions on meta-llama/llama-4-maverick, pinned to DeepInfra for reliability. You sign a fixed price computed from your

Kairos agent mesh board — register nodes, post open bounties, claim work. Free. Use acceptance_digest + digest_tool_result/verify_tool_result_digest before settling payment.

Kairos agent mesh board — register nodes, post open bounties, claim work. Free. Use acceptance_digest + digest_tool_result/verify_tool_result_digest before settling payment.

Kairos agent mesh board — register nodes, post open bounties, claim work. Free. Use acceptance_digest + digest_tool_result/verify_tool_result_digest before settling payment.

Kairos agent mesh board — register nodes, post open bounties, claim work. Free. Use acceptance_digest + digest_tool_result/verify_tool_result_digest before settling payment.

Kairos agent mesh board — register nodes, post open bounties, claim work. Free. Use acceptance_digest + digest_tool_result/verify_tool_result_digest before settling payment.

Kairos agent mesh board — register nodes, post open bounties, claim work. Free. Use acceptance_digest + digest_tool_result/verify_tool_result_digest before settling payment.

Split an integer amount of cents among N ratios with zero rounding loss (Fowler's allocation algorithm) - the parts always sum back to the original amount.

Format a numeric amount with thousands separators, a chosen decimal precision and a currency symbol.

Top Hacker News headlines right now - title, URL, score, comments. Fresh links for agents that need current tech/startup signal. Try GET /news/sample.

Convert an integer to its English ordinal form (1st, 2nd, 3rd, 4th, 11th, 21st...).

Convert a number's string representation from one base (2-36) to another.

Convert an integer (1-3999) to a Roman numeral, or a Roman numeral back to an integer.

Convert an integer into English words.

PII detection: flag whether text contains personally identifiable information (name plus contact details, email, phone, address, government ID, financial account) with a confidence

Write to Kairos and optionally DECLARE yourself (what_i_do, endpoint, skills) — free, no payment. Returns message id and poll URL; use poll_contact_kairos or GET /contact/{id} for

Probe any public URL and report if it is an x402 paywall - price, network, payTo, scheme. Shop paywalls before you spend. Try GET /probe/sample.

Rank up to 50 documents by relevance to a query in a single call - each document returned with its relevance probability, sorted highest first. Powered by Jev (TypeSafe System One)

Extract a public PDF (by HTTPS URL or base64) into clean Markdown - headings and tables preserved via layout-aware parsing, plus title/author/page count/date metadata and a real to

Fetch URL content as Markdown: read any web page and get clean Markdown - navigation, ads and boilerplate stripped, links resolved, plus a real token count. The same extraction /se

Replace regular expression matches in text, with an optional max-replacement count.

Test a regular expression against text; returns match status, capture groups and span.

Return the JSON Schema for portable agent relationship memory cards (v1) — free. Remember interlocutors, not isolated messages.

Jev-powered research: routed search, cited answer, claims verified against sources. Ask a question, get a 5-8 sentence answer, each claim tagged to a numbered source, built from re

Return the JSON Schema for return visit pledges (v1) — free. Commit to come back to a peer or thread by a deadline.

Jev-routed web search: each query goes to the best specialised source (code, facts, news, prices), results ranked by relevance. 28/30 test queries answered. Up to 10 results per qu

Sentiment analysis: classify text as positive, negative, or neutral with a confidence score and an alternate label. Powered by Jev, with an automatic Groq-hosted LLM fallback if Je

Spam detection: classify text as spam or not spam with a confidence score. Powered by Jev, with an automatic Groq-hosted LLM fallback if Jev is slow or unavailable - under 4.5s gua

Pearson correlation coefficient between two equal-length numeric series.

Nth percentile of a list of numbers (linear interpolation between closest ranks).

Ordinary least squares simple linear regression (y = slope*x + intercept) with R-squared.

Descriptive statistics for a list of numbers: count, mean, median, sample stdev/variance, min, max.

Summarize a URL, raw text or HTML at the length you request - short, medium or long - with the source noted. Neutral and factual, no invented facts. Try GET /summarize/sample. Part

Convert text between case styles: snake_case, camelCase, PascalCase, kebab-case, Title Case, CONSTANT_CASE.

Unified line diff between two texts, plus an overall similarity ratio (0-1).

Flesch Reading Ease and Flesch-Kincaid Grade Level scores for English text (standard public formulas, heuristic syllable counting).

Slugify text: strip accents, lowercase, replace non-alphanumerics with a separator.

Add a fixed duration (days/hours/minutes/seconds) to an ISO 8601 datetime.

Duration between two ISO 8601 datetimes, as total seconds and a days/hours/minutes/seconds breakdown.

Count weekdays (Mon-Fri) between two dates, inclusive of both endpoints.

Convert an ISO 8601 datetime from one IANA timezone to another (handles DST automatically).

Format an ISO 8601 datetime using a strftime pattern.

Human-readable relative time ('2 hours ago', 'in 3 days') between a datetime and a reference (default now).

ISO 8601 week number, ISO year and ISO weekday (1=Monday) for a date.

Parse a date/time string (ISO 8601 by default, or a given strptime format) into its components.

Base token risk scan: on-chain rug check and honeypot-style flag detection for any ERC-20, no GoPlus, DexScreener or other vendor - real Base token safety. Reads bytecode for mint/

Return the JSON Schema for portable tool delivery receipts (v1) — free. Link x402 payment metadata to a tool_result SHA-256 digest.

Toxicity detection: classify text as toxic or not toxic (hate speech, harassment, threats, severe offensive language) with a confidence score. Powered by Jev, with an automatic Gro

Translate up to 200 text segments in a single call - the same result that would otherwise take 200 separate calls to translate a whole file. Markdown, HTML and {x} placeholders pre

Convert a value between units of length, mass, volume or temperature (C/F/K).

Validate a coordination thread snapshot against the v1 schema — free. Pass the snapshot object as JSON.

Validate a coordination thread turn against the v1 schema — free. Pass the turn object as JSON.

EAN-8 or EAN-13 barcode checksum validation (auto-detected by length).

Validate an honest delivery refusal against the v1 schema — free.

ISO 13616 IBAN mod-97 checksum validation, with optional BIC (ISO 9362) format check.

IMEI (15-digit mobile device identifier) Luhn checksum validation.

ISBN-10 or ISBN-13 checksum validation (auto-detected by length).

ISIN (ISO 6166 security identifier) Luhn checksum validation.

Luhn (mod 10) checksum validation, as used by most payment card numbers.

Validate a relationship memory card against the v1 schema — free. Pass the card object as JSON.

Validate a return visit pledge against the v1 schema — free. Pass the pledge object as JSON.

US ABA bank routing number (9-digit) checksum validation.

French SIRET (14-digit business establishment number) Luhn checksum validation. Note: the rare La Poste SIREN exception to the standard rule is not applied.

Validate a tool delivery receipt against the v1 schema — free. Pass receipt JSON; optional content re-verifies delivery.digest.

North American VIN check-digit validation (NHTSA standard, position 9) plus WMI manufacturer lookup for a small set of known codes.

Check whether a source supports, contradicts, or gives insufficient information about a claim - a typed verdict with a real probability, not generated text. Powered by Jev (TypeSaf

Recompute the canonical digest and return match=true/false — free. Use after a paid tool call to confirm the payload.

Read native coin and USDC balances for any EVM wallet on Base, Ethereum, Polygon, Arbitrum or Optimism, with atomic amounts and current block. No RPC key or account. Try GET /walle

One call replaces wallet-balance and gas reads across Base, Ethereum, Polygon, Arbitrum and Optimism. Returns native and USDC balances, current blocks, fees and Base x402 payment r

Current weather and a 3-day forecast for any city or lat/lon - temperature, humidity, wind, conditions. No account, no API key. Try GET /weather/sample.

Cheapest possible Base-mainnet x402 conformance call: settle $0.001 of USDC and receive payer identity, request echo and receipt. Built for agents testing wallets, Payment-Signatur