Get Storage Capacity

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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered; the description still adds real behavioral context beyond them — the <10% threshold that determines inclusion, the interpretation rule that any returned row is a warning, and the Azure SQL Database unavailability. It does not describe pagination or column layout, but that is minor here.

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?

Four short clauses, zero filler, and the substantive content (scope, threshold, and the Azure exclusion) is front-loaded. Nothing can be removed without losing information.

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 no parameters, no output schema, and rich annotations, the remaining burden is small and mostly met: threshold, warning semantics, and availability limits are all stated. What a returned row actually contains is left unstated, though the "any row is a warning" rule lets an agent act on the result without knowing the columns.

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?

The tool takes zero parameters, so per the rubric the baseline is 4. There is nothing for the description to disambiguate, and it correctly spends no words on nonexistent inputs.

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 names the resource (drive free space) and the exact filter that defines the result set (drives with less than 10% free), which cleanly separates it from siblings like mssql_disk_io_latency and mssql_autogrowth_issues. The action verb is only implied by the title, not stated in the description itself.

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?

It gives explicit usage direction ("Include in every health check") and a hard platform exclusion ("Not available on Azure SQL Database"), which is exactly the kind of when-not guidance agents need. It stops short of naming alternative tools for adjacent disk concerns, so it is not a full when/when-not/alternatives treatment.

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