count_kb_file

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

With no annotations provided, the description carries the full burden. It adds meaningful behavioral detail by specifying the rounding method and the Windows Explorer compatibility, which goes beyond simply saying 'returns file size'. It does not disclose error behavior or what happens for non-file paths, but the core behavior is transparent.

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?

The description is extremely concise: one sentence defining behavior and formula, followed by the single argument's purpose. Every word adds value, and the key behavioral detail is front-loaded.

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?

For a simple single-parameter tool with an output schema, the description provides the essential formula, the matching behavior, and the path requirement. It is nearly complete, but omits edge-case behavior such as nonexistent files, directories, or permission failures.

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 0%, so the description must compensate. It does so by specifying that file_path is an 'Absolute path to the file', adding a meaningful constraint beyond the schema's bare string type. Since there is only one parameter and its role is clear, this is sufficient.

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 computes file size in KB using a specific formula, ceil(bytes / 1024), and explicitly matches Windows Explorer's display convention. This distinguishes it from sibling tools that count tokens, lines, or characters.

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?

The usage context is implied by the name and description: use this when you need a file's size in KB. However, there is no explicit guidance about when to prefer this tool over siblings, no exclusions, and no mention of invalid inputs such as nonexistent files or directories.

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