jwt_decode
Decode a JWT (JWS or JWE header), POST only (token in the JSON body, never in a URL): header, claims, alg/kid, exp/nbf/iat status with leeway, aud/iss checks, and security findings (alg none, HMAC alg-confusion risk, jku/x5u/jwk header keys, missing exp, odd kid). Optionally verifies the signatur...
This record as markdown: /tools/com-it-scorptech-x402/jwt-decode.md
What jwt_decode does on ScorpTech x402 API
AI agents call jwt_decode to retrieve information from ScorpTech x402 API 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 |
|---|---|---|---|
aud | string | — | Expected audience to check |
iss | string | — | Expected issuer to check |
token | string | Yes | Compact JWT in the JSON body (a "Bearer " prefix is stripped). Alias: jwt |
leeway | integer | — | Clock skew allowance in seconds, 0-600 (default 60) |
discover | boolean | — | Verify via OpenID discovery from the https iss claim when no jwks_url is given |
jwks_url | string | — | Optional JWKS (or single JWK) URL to verify the signature |
Parameters from the server's own tool schema.
Why jwt_decode is rated Low
Even though jwt_decode 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.
Risk signalsHandles credentials or secrets (token)
Attacks that exploit this kind of access
The rule that runs jwt_decode safely
PolicyLayer is an MCP gateway: it sits between your AI agents and ScorpTech x402 API, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For jwt_decode, this is the rule to start with:
jwt_decode 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 ScorpTech x402 API, apply this rule, and every jwt_decode call is checked against it from then on.
Questions about jwt_decode
Decode a JWT (JWS or JWE header), POST only (token in the JSON body, never in a URL): header, claims, alg/kid, exp/nbf/iat status with leeway, aud/iss checks, and security findings (alg none, HMAC alg-confusion risk, jku/x5u/jwk header keys, missing exp, odd kid). Optionally verifies the signature against a JWKS URL you supply, or one discovered from the token's https iss via OpenID discovery (fetched SSRF-safely): RS256/384/512, PS256/384/512, ES256/384/512, ES256K and EdDSA. Never trusts alg none. Price: $0.005 USDC per successful call (x402, Solana). Same tool over HTTPS: POST https://scorptech.it.com/api/x402/v1/jwt-decode. It is categorised as a Read tool in the ScorpTech x402 API MCP Server, which means it retrieves data without modifying state.
jwt_decode accepts 6 parameters: aud, iss, token, leeway, discover, jwks_url. Required: token. The full parameter table on this page comes from the server's own tool schema.
Register the ScorpTech x402 API MCP server in PolicyLayer and add a rule for jwt_decode: 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 ScorpTech x402 API. Nothing to install.
jwt_decode 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 jwt_decode 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 jwt_decode. 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.
jwt_decode is provided by the ScorpTech x402 API MCP server (https://scorptech.it.com/api/x402/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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