Select JSON values with up to 100 RFC 6901 pointer strings, preserving missing versus null. 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 |
|---|---|---|---|
| selections | 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 readOnly, non-destructive, closed-world behavior, and the description adds genuinely new context: preserving missing versus null semantics, the 100-pointer ceiling, no-auth/no-prep, and that source/input limits apply. It still does not describe output shape, but the output schema presumably covers that.
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 purpose is front-loaded, which is good, but the marketing-style lines ('FREE during validation. No key, credits, wallet or preparation needed.') and the filler 'Supply your task in input' consume space without informing invocation. Mixed efficiency.
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 an output schema present, return values need no explanation, and the missing-vs-null behavior is a useful addition. However, for a nested one-parameter tool at 0% schema coverage, the input structure (data/paths relationship, expected data types) is under-specified, leaving the agent to infer it.
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%, so the description must carry the load. It does document the paths side ('up to 100 RFC 6901 pointer strings'), but the 'data' field and the nested input wrapper are never explained beyond the vague 'Supply your task in input', leaving a real 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?
The description states a specific verb+resource ('Select JSON values') and pins the format to RFC 6901 pointers, which clearly separates it from siblings like data_json_diff, data_json_patch, and data_json_canonical. It does not explicitly name those siblings, so it falls short of the 5 bar, but the operation 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?
There is no when-to-use or when-not-to-use guidance relative to the other data_json_* tools, and 'Supply your task in input' is vague rather than a usage instruction. 'FREE during validation' hints at a context but never states the conditions under which this tool should be chosen.
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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