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

Adds that it is read-only, stat-only, no side effects, returns JSON with per-directory byte counts. Annotation readOnlyHint=true is confirmed and expanded with behavioral details.

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 concise sentences, front-loaded with purpose and behavior, no unnecessary words.

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?

No output schema, but description explains the output (JSON with per-directory byte counts). For a simple tool with full annotations and schema, the description is complete.

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 coverage is 100%, so baseline 3. The description does not add meaning beyond the schema; it does not describe parameters or their semantics.

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 clearly states the tool estimates file and directory space usage recursively as JSON, and distinguishes it from 'df' for filesystem-level overview. Specific verb and resource.

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?

Explicitly says when to use (find space-consuming directories/files) and when not (not for filesystem-level overview, use 'df'). Names sibling tools 'df' and 'stat' as alternatives.

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