Compare environment-variable names against a template; never returns assignment values. FREE during validation. No key, credits, wallet or preparation needed. Supply your task in input. Existing source and input limits apply.
| Name | Required | Description | Default |
|---|---|---|---|
| input | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| extra | Yes | ||
| scope | Yes | ||
| missing | Yes | ||
| duplicateNames | Yes | ||
| unrecognizedLines | Yes | ||
| templateDuplicateNames | Yes |
Changes observed during successful MCP inspections.
Input schema / properties / maxPriceMicroUsdRemoved value: -{
- "description": "Optional legacy field; ignored in free mode.",
- "minimum": 0,
- "type": "integer"
-}Input schema / properties / requestIdRemoved value: -{
- "description": "Optional legacy field; ignored in free mode.",
- "type": "string"
-}Input schema / properties / maxPriceMicroUsd / descriptionPrevious value: -"Explicit maximum new debit; 0 means recovery only."New value: +"Optional legacy field; ignored in free mode."Input schema / properties / maxPriceMicroUsd / maximumRemoved value: -999999999999Input schema / properties / requestId / descriptionPrevious value: -"Persist the ID returned by agent_utilities_prepare. Reuse after uncertainty."New value: +"Optional legacy field; ignored in free mode."Input schema / properties / requestId / patternRemoved value: -"^\\d{13}_[A-Za-z0-9_-]{16,80}$"Input schema / requiredPrevious value: -[
- "input",
- "requestId",
- "maxPriceMicroUsd"
-]New value: +[
+ "input"
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds real value beyond them by disclosing that assignment values are never returned (a privacy/output-content guarantee) and that "existing source and input limits apply" — concrete behavioral constraints not present in 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 core purpose is correctly front-loaded in the first clause, but the middle sentences are marketing filler ("FREE during validation", "No key, credits, wallet or preparation needed") that do not help an agent invoke the tool, and "Supply your task in input" is near-empty.
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 no explanation, and the read-only annotations cover the safety profile. That said, for a comparison tool with a nested two-field input and no parameter documentation at all, the description leaves the agent guessing about the input format.
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 0% and the single input object nests two required string properties (template, actual) with no documented meaning anywhere. The description says only "Supply your task in input," which adds no information about what template vs actual should contain, their expected format (env-var lines?), or the 100000-char limit. It fails to compensate for the coverage gap.
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?
"Compare environment-variable names against a template" gives a specific verb (compare) and a specific resource (env-var names vs template), so the agent knows exactly what operation occurs. It does not name or distinguish itself from any sibling tool, so it stops short of a 5.
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 only usage-adjacent sentences are commercial notes ("FREE during validation", "No key, credits, wallet or preparation needed") and the vague "Supply your task in input." There is no statement of when to use this versus alternatives, nor any precondition for invocation.
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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