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lucastl

Agentic MCP Server

by lucastl

atomic-writer

Write file content securely with automatic backups and path validation. Prevents accidental overwrites and ensures safe file operations.

Instructions

Writes file content with automatic backup creation and path safety validation.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
pathYesFilesystem path to write, relative or absolute to the project root.
contentYesContent to persist to the target file.

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
pathYes
bytesWrittenYes
backupCreatedYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv1.0.0

TDQS

B3.3/5.0
Behavior3/5

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

With no annotations, the description carries the burden of behavioral disclosure. It does disclose two meaningful behaviors: backup creation and path safety validation. However, it omits notable traits such as atomicity (despite the tool name 'atomic-writer'), overwrite behavior, permission requirements, or what happens if a backup already exists.

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?

A single, front-loaded sentence that names the action first and then packs in the two key behavioral traits. No filler or redundant restating of the schema.

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

Completeness3/5

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

For a mutation tool with no annotations, the description is somewhat thin. It covers what and key safety behaviors, and an output schema exists so return values need not be described. But it lacks usage routing, explicit mention of atomicity, and clarification of overwrite semantics, leaving an agent to infer important invocation context.

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 schema fully documents both path and content. The description adds no parameter-specific meaning beyond the schema, so the baseline of 3 is appropriate.

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

Purpose4/5

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

States a specific verb and resource: 'Writes file content', and adds distinguishing features (automatic backup creation, path safety validation). It is clearly a write tool and not a read or planning tool, but it does not explicitly differentiate itself from sibling write-capable tools like terminal-runner.

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

Usage Guidelines2/5

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

No guidance on when to use this tool versus alternatives. The description does not mention that fs-reader should be used for reading, or that terminal-runner might be an alternative for shell-based writes. Usage context is entirely implied by the tool name and description.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.