list_verification_tiersList Web Evidence verification tools, prices, and research limits. This tool is free.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
| tiers | Yes |
Changes observed during successful MCP inspections.
Input schema / $schemaRemoved value: -"http://json-schema.org/draft-07/schema#"Output schema / (root)Previous value: -nullNew value: +{
+ "$schema": "http://json-schema.org/draft-07/schema#",
+ "additionalProperties": false,
+ "properties": {
+ "tiers": {
+ "items": {
+ "additionalProperties": false,
+ "properties": {
+ "maxSources": {
+ "description": "Maximum evidence sources available in this tier.",
+ "type": "integer"
+ },
+ "priceUsd": {
+ "description": "Per-call price in US dollars.",
+ "type": "string"
+ },
+ "summary": {
+ "description": "Human-readable tier capabilities.",
+ "type": "string"
+ },
+ "tool": {
+ "description": "MCP tool name for this verification tier.",
+ "type": "string"
+ }
+ },
+ "required": [
+ "tool",
+ "priceUsd",
+ "maxSources",
+ "summary"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ }
+ },
+ "required": [
+ "tiers"
+ ],
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior. The description adds genuinely new context the annotations lack: that this call costs nothing, which matters relative to the paid verify tiers. It stops short of describing rate limits or freshness of the listed prices.
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?
Two short sentences, front-loaded with the resource being listed and followed by the cost fact. Nothing is padded or redundant.
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?
For a zero-parameter listing tool with an output schema already present, the description tells the agent what will be returned (tools, prices, research limits) and that the call is free. Return-value detail is rightly left to the output schema.
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?
The tool takes zero parameters, so the baseline is 4. The description correctly implies a no-argument listing operation and adds no misleading parameter expectations.
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?
States a specific verb (List) and resource (Web Evidence verification tools, prices, research limits), which is clearly distinct from the verify_claim* action siblings. It does not explicitly name a sibling, but the listing-vs-verifying distinction is unambiguous.
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?
The phrase 'This tool is free' hints at a cost-driven reason to call it (e.g., checking prices before choosing a paid verify tier), but there is no explicit when-to-use or when-not-to-use statement and no named alternative. Usage is only implied.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.