tengu_crypto
Live crypto quote from the market-data feed (real-time entitlement, 439 pairs): last-trade price, 24h change/volume (UTC-day basis), day + prev-day OHLC, optional last-7 daily bars, honest as_of. PRIMARY tool for 'what is BTC at?' — accepts BTC/BTCUSD/X:BTCUSD plus a vs currency (e.g. EUR); unkno...
This record as markdown: /tools/tengu-mcp/tengu-crypto.md
What tengu_crypto does on Tengu
AI agents call tengu_crypto to retrieve information from Tengu without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
vs | string | — | |
series | boolean | — | |
ticker | string | Yes | Path parameter 'ticker' (required). |
Parameters from the server's own tool schema.
Why tengu_crypto is rated Low
Even though tengu_crypto only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Attacks that exploit this kind of access
The rule that runs tengu_crypto safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Tengu, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For tengu_crypto, this is the rule to start with:
tengu_crypto is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Tengu, apply this rule, and every tengu_crypto call is checked against it from then on.
Questions about tengu_crypto
Live crypto quote from the market-data feed (real-time entitlement, 439 pairs): last-trade price, 24h change/volume (UTC-day basis), day + prev-day OHLC, optional last-7 daily bars, honest as_of. PRIMARY tool for 'what is BTC at?' — accepts BTC/BTCUSD/X:BTCUSD plus a vs currency (e.g. EUR); unknown symbols return a structured 404. It is categorised as a Read tool in the Tengu MCP Server, which means it retrieves data without modifying state.
tengu_crypto accepts 3 parameters: vs, series, ticker. Required: ticker. The full parameter table on this page comes from the server's own tool schema.
Register the Tengu MCP server in PolicyLayer and add a rule for tengu_crypto: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Tengu. Nothing to install.
tengu_crypto is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the tengu_crypto rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for tengu_crypto. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
tengu_crypto is provided by the Tengu MCP server (Hlobo-dev/tengu-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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