verify_jwt
utilpeek: Verify a JWT signature and claims. To read the claims without a key use decode_jwt. Returns valid true or false for a JWT checked with PyJWT against one key (HMAC secret, PEM public key or JWK Set), with a reason: bad signature, expired, wrong audience or issuer, algorithm not allowed. ...
This record as markdown: /tools/dev-tanod-tanod/verify-jwt.md
What verify_jwt does on Tanod
AI agents call verify_jwt to retrieve information from Tanod 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 |
|---|---|---|---|
jwks | object | — | JWK Set object {"keys": [...]} (asymmetric keys; oct keys are ignored). The key is picked by the token kid. |
token | string | Yes | Compact JWT to verify. |
issuer | object | — | Required iss. |
secret | object | — | HMAC secret (HS256/384/512). |
audience | object | — | Required aud (a string, or a list of which one must match). |
algorithms | object | — | Allow-list that narrows the default for the key type; none is refused. |
public_key | object | — | PEM public key (RS*, PS*, ES*, EdDSA). |
leeway_seconds | integer | — | Clock skew allowed for exp, nbf and iat (0-300). |
Parameters from the server's own tool schema.
Why verify_jwt is rated Low
Even though verify_jwt 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 verify_jwt safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Tanod, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For verify_jwt, this is the rule to start with:
verify_jwt 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 Tanod, apply this rule, and every verify_jwt call is checked against it from then on.
Questions about verify_jwt
utilpeek: Verify a JWT signature and claims. To read the claims without a key use decode_jwt. Returns valid true or false for a JWT checked with PyJWT against one key (HMAC secret, PEM public key or JWK Set), with a reason: bad signature, expired, wrong audience or issuer, algorithm not allowed. Algorithm none is refused; the key type fixes the algorithm family. Input: token and exactly one of secret, public_key or jwks; optional algorithms, audience, issuer, leeway_seconds. Pure computation, no network; secrets and keys are not echoed. A failed check is a normal charged result (valid false). No JWKS URL fetch: send the key set. Malformed input is a 422 (not charged). Typically under 0.1 s. Price: USD 0.001. Free: 10 utilpeek calls per IP per UTC day. The submitted text is never logged or stored. Docs: https://tanod.dev/learn/jwt-decode-verify-api.html. It is categorised as a Read tool in the Tanod MCP Server, which means it retrieves data without modifying state.
verify_jwt accepts 8 parameters: jwks, token, issuer, secret, audience, algorithms, public_key, leeway_seconds. Required: token. The full parameter table on this page comes from the server's own tool schema.
Register the Tanod MCP server in PolicyLayer and add a rule for verify_jwt: 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 Tanod. Nothing to install.
verify_jwt 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 verify_jwt 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 verify_jwt. 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.
verify_jwt is provided by the Tanod MCP server (https://tanod.dev/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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