Free. Lists every paid tool on this server with its price in USDC (Base), what it returns, the equivalent HTTP x402 endpoint and which tools have a free daily trial call.
This tool declares no required parameters. Add optional parameters from the input schema as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {},
"name": "list_services"
}
}| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description carries the full burden and does disclose the key traits: zero cost, currency and chain of the quoted prices (USDC on Base), and the presence of trial-call availability per tool. It does not mention auth requirements, pagination, or output format, though for a zero-param read-only listing these are minor.
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 dense sentence with the most decision-relevant fact ('Free') front-loaded, then the payload contents. Nothing is repeated and nothing is padding.
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?
With no output schema, the description must describe the return contents, and it does: price, return value, equivalent endpoint, trial availability. It could say slightly more about the shape of the response (e.g. one entry per tool) or how the x402 endpoint string is meant to be used, but an agent has enough to call it correctly.
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 no parameters, so the baseline is 4. The description correctly adds no parameter discussion, leaving nothing ambiguous about invocation.
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 (lists) and resource (every paid tool on this server) plus the exact fields returned: price in USDC on Base, what it returns, matching x402 HTTP endpoint, and free-trial availability. This is clearly a free discovery/meta tool, trivially distinguishable from all the paid siblings it enumerates.
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 leading 'Free.' signals this is the no-cost entry point before invoking the paid siblings, which is useful routing context. It stops short of explicitly saying 'use this first to discover tools, then call the paid tool' or stating any when-not condition.
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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