Validate declared OAuth audience and issuer; never send raw tokens; 0.002 USDC.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Input schema / examplesAdded value: +[
+ {
+ "claims": {
+ "aud": "https://api.example",
+ "iss": "https://auth.example"
+ },
+ "expected_audience": "https://api.example",
+ "expected_issuer": "https://auth.example"
+ }
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, but it does disclose two non-obvious traits: raw tokens are never transmitted ('never send raw tokens') and there is a per-call cost ('0.002 USDC'). It omits failure semantics, permission requirements, and what a validation verdict looks like, so the behavioral picture is partial.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single compact sentence with the purpose front-loaded and the privacy and cost caveats trailing. Nothing is wasted, though the terseness comes at the cost of the missing usage guidance noted elsewhere.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
An output schema exists, so return values need not be described, and the description covers purpose, privacy posture, and pricing. It remains incomplete on when to select this guard over its many security siblings and on what a negative result means for the caller.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100% and an example illustrates the claims/expected_issuer/expected_audience shape, so the schema does the heavy lifting. The description adds no parameter meaning beyond that, which is the expected baseline when coverage is complete.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific verb and resource: 'Validate declared OAuth audience and issuer.' That is concrete and distinguishable from generic validation tools. It does not, however, differentiate itself from close siblings like oauth_issuer_binding_evidence, leaving the agent to infer the boundary.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no guidance on when to call this versus alternatives such as oauth_issuer_binding_evidence or delegated_credential_guard, and no preconditions or exclusions are stated. The agent must infer the usage context from the name alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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