I used the same url for two different postings.
Queries public GitHub repo stars, open issues, licenses, and push activity ($0.002 USDC)
| Name | Required | Description | Default |
|---|---|---|---|
| repository | Yes | GitHub repository in owner/repo format |
| Name | Required | Description | Default |
|---|---|---|---|
| stars | Yes | Repository star count | |
| license | No | SPDX license identifier | |
| success | Yes | Analysis status |
Changes observed during successful MCP inspections.
Input schema / properties / repository / descriptionAdded value: +"GitHub repository in owner/repo format"Output schema / (root)Previous value: -nullNew value: +{
+ "properties": {
+ "license": {
+ "description": "SPDX license identifier",
+ "type": "string"
+ },
+ "stars": {
+ "description": "Repository star count",
+ "type": "integer"
+ },
+ "success": {
+ "description": "Analysis status",
+ "type": "boolean"
+ }
+ },
+ "required": [
+ "success",
+ "stars"
+ ],
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, covering the safety and data-source profile. The description adds only the cost ($0.002 USDC), which is useful extra context. It does not contradict annotations and provides adequate transparency for a read-only query tool.
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, front-loaded sentence conveys the action, scope, and data points with zero waste. The cost is appended at the end, making it both concise and complete.
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?
The tool is simple (one parameter, output schema present, safety annotations provided). The description includes the cost and the exact data being retrieved. Nothing an agent needs to call it correctly 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?
Schema coverage is 100%—the single parameter 'repository' is fully described in the schema ('GitHub repository in owner/repo format'). The description adds no extra parameter details, so the baseline of 3 applies.
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 ('Queries'), a specific resource ('public GitHub repo'), and enumerates the exact data points (stars, open issues, licenses, push activity). This clearly distinguishes it from all sibling tools, which are unrelated (weather, shipping, etc.).
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?
No explicit when-to-use or alternatives are provided. However, the tool name and description make its purpose obvious (any GitHub repo health query). Since siblings are unrelated, no exclusions are needed, but the description could have stated 'Use for GitHub repo metrics' to be more explicit.
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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