CoinGecko API

Use this skill for any request involving cryptocurrency market data, coin prices, trading volume, market cap, OHLC charts, historical data, exchanges, deriva...

Security Scan

The skill's files and runtime instructions are internally consistent with a CoinGecko/GeckoTerminal API integration and do not request unrelated capabilities or suspicious installs.

Purpose & Capability

Name/description (crypto market data, CoinGecko/GeckoTerminal) match the included references and runtime instructions. The listed endpoints, workflows, and trigger rules are coherent for the stated purpose.

Instruction Scope

SKILL.md limits actions to fetching live market/on-chain data, checking credentials/allowlists, and building visualizations. It explicitly forbids using training data for prices and instructs the agent to pause on failed calls. There are no instructions to read unrelated system files or send data to endpoints outside CoinGecko/GeckoTerminal and recommended MCP docs.

Install Mechanism

This is an instruction-only skill with no install spec or code to fetch/execute. README suggests optional external install paths (GitHub/npm) but the skill package itself performs no downloads or extraction during runtime.

Credentials

The skill relies on an API key / plan tier for some endpoints and instructs the agent to check memory or ask the user for credentials, but the registry metadata lists no required env vars. This is not intrinsically malicious, but consumers should note the skill will prompt for API credentials and may look in agent memory for stored keys—ensure keys are provided via a secure secret mechanism rather than pasted into chat.

Persistence & Privilege

No elevated privileges requested: always is false, no install-time modifications or cross-skill config changes are described. Autonomous invocation is allowed by default but not combined with other red flags here.

Assessment

This skill appears coherent for accessing CoinGecko and GeckoTerminal data. Before installing or using it: (1) verify the skill's source/maintainer (README points at CoinGecko docs but the registry owner ID is not obviously the official org); (2) never paste private secrets (API keys, wallet seed phrases) into an open chat—use your agent platform's secret storage or provide keys via a secure UI if available; (3) if running inside Claude, follow the SKILL.md allowlist and bash_tool guidance (api.coingecko.com / pro-api.coingecko.com) as instructed; (4) if you plan to run any generated curl/python/node code locally, inspect it first; and (5) if you have doubts about provenance, prefer fetching the official skill repository from the vendor's verified GitHub or their documentation links before installing.

CoinGecko Skill

When to use

Trigger this skill when the user's request matches any of the following:

Crypto market data queries

• Coin/token prices, market caps, trading volume, price changes
• Historical price data, OHLC charts, time-range queries
• Circulating or total supply data
• Global crypto market stats (total market cap, BTC dominance, DeFi TVL)
• Trending coins, top gainers/losers, newly listed coins

Token and contract lookups

• Looking up a token by its contract address (e.g. 0x...)
• Token metadata, categories, or platform info
• Comparing multiple coins or tokens

Exchange and trading data

• Exchange listings, volume, tickers, trust scores
• DEX-specific data (Uniswap, PancakeSwap, etc.)
• Derivatives exchanges and tickers (futures, perpetuals)

On-chain / DeFi data (GeckoTerminal)

• Liquidity pool data, trending/new pools, pool search
• On-chain token prices, holder data, top traders
• OHLCV candles or trade history for specific pools or tokens
• DEX and network discovery (supported chains, DEXes)
• On-chain pool categories and filtering

NFT data

• NFT collection prices, floor prices, market data
• NFT collection charts and tickers

Other triggers

• Building dashboards, visualizations, or apps with crypto data
• Questions about CoinGecko or GeckoTerminal API capabilities, endpoints, or rate limits
• API key setup, authentication, plan tiers, or pricing questions
• "What crypto data is available?" or similar exploratory questions
• User mentions CoinGecko, GeckoTerminal, or shares a CoinGecko URL
• Investment calculators, portfolio trackers, or ROI calculations involving crypto
• Public company/institution crypto treasury holdings (e.g. "how much BTC does MicroStrategy hold?")

---

You have access to the CoinGecko API (aggregated data) and the GeckoTerminal API (on-chain DEX data). Together they cover virtually all crypto market data needs. Both APIs share the same API key and plan tier. GeckoTerminal endpoints use the same base URL as CoinGecko plus an /onchain path prefix (details in references/core.md).

STRICT RULE — All market data must come from live API calls

Never answer questions about crypto prices, market caps, volumes, supply, TVL, exchange rates, or any time-sensitive market data using training knowledge. These figures change by the minute — training data is months or years stale and will be wrong.

If an API call fails or has not been attempted yet, you MUST:

1. Stop. Do not answer the data question.
2. Tell the user the data could not be fetched (or hasn't been fetched yet).
3. Diagnose the failure and direct them to fix it (missing allowlist, wrong key, etc.).

Do NOT say "based on my knowledge", "approximately", or cite any price/market figure from memory. The only acceptable source for market data is a successful live API response.

Bad: "The domain is blocked… However, I have reliable data. Bitcoin today: ~$87,000" (actual price was ~$69,000 — Claude fabricated a confident, wrong answer)

Good: "The API call failed because the domain is blocked. Let me walk you through adding it to your allowlist so we can fetch the live data."

Workflow

Follow these steps in strict order. Do NOT skip ahead. Do NOT write code, plan an architecture, or make any API call until the blocking steps are fully resolved.

Step 0a — Claude environment check (BLOCKING — Claude only)

If you are running inside Claude (claude.ai), read references/claude-env.md first. It documents two platform constraints that break all CoinGecko API calls:

1. Domain allowlist — the user must add api.coingecko.com and pro-api.coingecko.com at claude.ai/settings/capabilities. If this is the user's first time or any call fails with a network error, pause and walk them through it before debugging anything else.
2. Artifact sandbox — fetch() inside Artifacts will always fail silently. Default to bash_tool with curl for all CoinGecko API calls, then embed results as static data into any Artifact or visualization. This is the standard approach, not a fallback.

Skip this step if not running inside Claude.

Step 0b — Confirm credentials (BLOCKING)

STOP. Before doing anything else, you must resolve the user's API tier. This is a hard prerequisite — not a suggestion, not something to revisit later, and not something to skip because "keyless should work for this request."

Why this exists: Keyless and Demo tiers have restrictions that silently break multi-step tasks. Example failure pattern:

User: "If I invested in Bitcoin 5 years ago, how much would it be worth today?" Bad behavior: Claude assumes keyless works, starts building a dashboard, then hits error 10012 because keyless/Demo cannot fetch historical data beyond 365 days. The user wasted time and rate-limit calls on something that was never going to work.

The correct behavior is to ask for credentials first, identify that "5 years ago" exceeds keyless/Demo limits, and tell the user upfront — before writing a single line of code.

Procedure:

1. Check memory for a previously saved plan tier and API key.
2. If found, confirm they are still current. If not found, ask the user:
   • Plan tier — paid (Pro) or free (Demo)?
   • API key — their CG-… key?
3. No key? Only fall back to keyless after the user explicitly says they have no key. If the user simply hasn't mentioned a key, ask — do not treat silence as "no key." When proceeding keyless, warn: capped at 5 calls/min, unstable, and data restrictions apply. Suggest a free Demo key at https://www.coingecko.com/en/api/pricing.
4. Assess feasibility against the confirmed tier. Check whether the request involves data or endpoints that exceed the tier's limits — e.g. historical data beyond 365 days (keyless/Demo), Enterprise-only intervals (5m), or paid-only endpoints. If it does, tell the user before attempting any call. Do not make the call and let it fail.
5. Read references/core.md for full auth setup and save the confirmed tier to memory.

Do NOT proceed to step 1 until this step is fully resolved.

Step 1 — Identify the domain

Use the Reference index below to decide which file(s) to load.

Step 2 — Load references and construct the request

Load the relevant reference file(s) and build the API call.

Step 3 — Execute and handle errors

Auth and rate-limit error codes are documented in references/core.md. If the API returns error 10005, the endpoint requires a higher plan — inform the user and link them to https://www.coingecko.com/en/api/pricing. If you get error 10010 or 10011, you've used the wrong base URL for the key type — swap URLs per core.md's error table and retry automatically.

"Failed to fetch" or network errors: If a request fails with no HTTP status (e.g. "Failed to fetch", TypeError), follow the diagnostic in references/claude-env.md if running inside Claude — the cause is usually the Artifact CSP sandbox (move to bash_tool) or a missing domain allowlist entry. Outside Claude, the cause is likely a wrong base URL — see core.md's "Network-level failures" section. In either case, never assume CORS is the problem.

Reference index

Load the relevant reference file based on what the user is asking for. You only need to load the file(s) that match the current request.

Inspiration & Use cases

If the user asks what they can build, wants project ideas, or asks an exploratory question like "what data is available?" — load references/common-use-cases.md instead of the domain-specific files below, then follow its pointers to drill deeper.

Environment

File	When to load
references/claude-env.md	Read in Step 0a — Claude-specific constraints (domain allowlist, Artifact CSP sandbox, bash_tool strategy, MCP upgrade path). Only applies when running inside Claude.

CoinGecko (aggregated)

File	When to load
references/core.md	Always read — auth, methodology, rate limits
references/coins.md	Coin prices, market data, metadata, tickers, gainers/losers
references/coin-history.md	Historical charts, OHLC, time-range queries by coin ID
references/coin-supply.md	Circulating/total supply charts
references/contract.md	Coin data or charts looked up by token contract address
references/asset-platforms.md	Blockchain platform IDs, token lists
references/categories.md	Coin categories and sector market data
references/exchanges.md	Spot and DEX exchange data, tickers, volume charts
references/derivatives.md	Derivatives exchanges and tickers
references/treasury.md	Public company/institution crypto treasury holdings
references/nfts.md	NFT collection data, market data, charts, tickers
references/global.md	Global market stats and DeFi data
references/utils.md	API status, API key usage, supported currencies, search, trending coins/NFTs/categories, exchange rates

GeckoTerminal (on-chain)

File	When to load
references/onchain-networks.md	Supported networks and DEXes (ID resolution)
references/onchain-pools.md	Pool discovery, trending/new pools, megafilter
references/onchain-tokens.md	Token data, price by contract address, holders and traders
references/onchain-ohlcv-trades.md	OHLCV candles and trade history for pools/tokens
references/onchain-categories.md	On-chain pool categories (GeckoTerminal-specific)

General guidance

• If a request spans multiple domains (e.g. coin price + exchange data), load multiple reference files.
• When uncertain which file to load, check the index above before answering.
• For CoinGecko vs GeckoTerminal preference, see references/core.md (Methodology section).