Convert a JSON array of objects to CSV format. Automatically detects columns from all object keys. Handles quoting and escaping per RFC 4180.
| Name | Required | Description | Default |
|---|---|---|---|
| input | Yes | The array of objects to convert — a JSON string, or the array itself. | |
| headers | No | Include header row (default: true) | |
| delimiter | No | Column delimiter (default: ",") |
| Name | Required | Description | Default |
|---|---|---|---|
| csv | No | ||
| rows | No | ||
| columns | No | ||
| column_names | No |
Changes observed during successful MCP inspections.
Input schema / examplesAdded value: +[
+ {
+ "input": [
+ {
+ "a": 1
+ },
+ {
+ "b": 2
+ }
+ ]
+ }
+]Input schema / properties / input / descriptionPrevious value: -"JSON string containing an array of objects"New value: +"The array of objects to convert — a JSON string, or the array itself."Input schema / properties / input / typePrevious value: -"string"New value: +[
+ "string",
+ "object",
+ "array"
+]Output schema / propertiesAdded value: +{
+ "column_names": {},
+ "columns": {
+ "type": "number"
+ },
+ "csv": {
+ "type": "string"
+ },
+ "rows": {
+ "type": "number"
+ }
+}Output schema / (root)Previous value: -nullNew value: +{
+ "additionalProperties": true,
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds real behavioral value — column detection across all object keys and RFC 4180 quoting/escaping — but stays silent on how nested objects, arrays, nulls, or missing keys are rendered, which is the main behavioral unknown for a converter.
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?
Three short sentences, front-loaded with the conversion direction, then the column-detection rule and the escaping guarantee. Nothing is redundant.
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 annotations plus full schema coverage handle safety and parameters. The one gap is nested/array value handling and header behavior for heterogeneous keys, which an agent would want to know before calling.
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 100% and every parameter (input, headers, delimiter) carries its own default and type documentation. The description adds no parameter-level detail beyond the schema, so the baseline 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?
States a specific verb and resource ('Convert a JSON array of objects to CSV format'), making the direction of conversion unambiguous and implicitly the inverse of the sibling parse_csv. It stops short of naming that sibling explicitly, so the differentiation is inferred rather than stated.
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?
Usage is implied by the name and the one-line purpose — an agent can tell this is the JSON-to-CSV direction. There is no explicit statement of when to prefer it over parse_csv or yaml_to_json, and no exclusions or preconditions.
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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