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Write rows

sheet_write

Write rows to spreadsheet files in xlsx, csv, tsv, or json format. Create new files, append to existing data, or overwrite file contents while preserving other sheets.

Instructions

Call this tool to write rows to an xlsx, csv, tsv or json file; the extension of out_path picks the format. mode is new_file, append or overwrite. Other sheets are kept. Free: 500 rows per file.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
modeYesnew_file writes a brand new file and refuses to clobber an existing one; append adds the rows under the existing data; overwrite replaces the file contents
pathYesSource file for append/overwrite, or the intended file for new_file (~ is expanded)
rowsYesArray of objects, whose keys become the headers, or an array of arrays with the header row first
sheetNoSheet to write; default is the first sheet of the source, or "Sheet1" for a new file. Other sheets of an existing workbook are kept unchanged
out_pathNoWhere to write; default is a new file next to the source for new_file, or the source itself for append/overwrite. The output format follows this extension: .xlsx, .csv, .tsv or .json. An extension is required

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.20.0

TDQS

A4/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the behavioral disclosure burden. It adds useful side-effect and quota context: 'Other sheets are kept' and 'Free: 500 rows per file.' However, it only lists the mode names without warning that overwrite replaces file contents or that new_file refuses to clobber, leaving destructive semantics to the schema.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three short sentences with no wasted content. It front-loads the primary purpose, then covers modes, then adds the safety/limit note. The only mild filler is the generic 'Call this tool to' opener.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 5-parameter write tool with a rich 100%-covered schema, the description plus schema covers formats, modes, sheet retention, defaults, and the row limit. It does not describe return/status behavior or explicit exclusions, but those are minor for a write operation and not required by the output schema absence.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description reinforces that out_path's extension selects the format and that mode takes three values, but both facts already appear in the input schema. It adds no genuinely new parameter semantics beyond a compact summary.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'write rows to an xlsx, csv, tsv or json file.' It clearly names the target formats and the mechanism for choosing format via 'the extension of out_path picks the format.' This distinguishes it from sibling read/query/load tools without merely restating the title.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

'Call this tool to write rows...' is a direct usage instruction, and the enumeration of modes (new_file, append, overwrite) tells the agent which write behaviors exist. It does not explicitly name alternatives or when-not-to-use conditions, but the write-oriented purpose is unambiguous against the sibling set.

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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