mpp_author_finderFind the email address of the author of a blog post or article using MPP (Machine Payments Protocol). Pay-per-request, no API key required.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | The URL of the article or blog post |
| Name | Required | Description | Default |
|---|---|---|---|
| data | Yes |
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "$schema": "http://json-schema.org/draft-07/schema#",
+ "additionalProperties": false,
+ "properties": {
+ "data": {}
+ },
+ "required": [
+ "data"
+ ],
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark the tool readOnly and openWorld, so the bar is lower. The description adds genuinely useful behavior beyond annotations: the request is pay-per-request and requires no API key. There is no contradiction with the annotations.
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?
The description is two short sentences that front-load the purpose and then state the key operational caveats: MPP, pay-per-request, and no API key. There is no filler, repetition, or irrelevant detail.
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 one-parameter tool with full schema coverage, read-only/open-world annotations, and an output schema, the description covers everything needed to select and call the tool correctly: what it does, its input, its payment model, and its auth requirements. No critical context is missing.
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 input schema already describes the only parameter, url, at 100% coverage as 'The URL of the article or blog post'. The description echoes that the URL should point to an article or blog post, but adds little parameter-specific meaning beyond what the schema already provides.
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 uses a specific verb ('Find') and a clear resource ('email address of the author of a blog post or article'), which makes the tool's purpose unmistakable. It also identifies this as the MPP variant by naming the protocol, helping to separate it from siblings like author_finder.
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 description gives clear operational context: use this tool when you need an author's email for an article/blog post and want pay-per-request access via MPP without an API key. It does not explicitly exclude alternatives or say 'use X instead', but the context is sufficient for practical routing.
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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