scan_folder

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

Annotations already cover read-only and non-destructive behavior, but the description goes beyond them by disclosing that it does not open files, uses stat info only (hence fast), cannot distinguish scanned vs text PDFs, and that truncation occurs when total_matched != returned. These are non-obvious behaviors an agent needs to know to interpret results correctly.

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 well-structured with clear sections (Args, Returns, Examples) and front-loaded with the primary purpose and speed caveat. It is slightly longer than strictly necessary, but every sentence contributes either to usage guidance or behavioral transparency. The use of bold and code formatting aids readability without padding.

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 an output schema present, the description correctly focuses on when to use, limitations, truncation handling, and sibling routing. It covers all operational concerns an agent would have: speed, PDF-type ambiguity, pagination/truncation, and path conventions. Nothing critical is missing for correct invocation.

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 input schema already documents all three parameters with full coverage (100%). The description does not add new semantic value beyond restating parameter purposes; it does give usage context for extensions (optional filter) and the folder default, but these are also in the schema. This matches the baseline for high schema coverage.

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 states a specific verb ('list') and resource ('documents in a folder'), and immediately distinguishes itself from siblings by noting it does not open files. It also clarifies it only reads stat information, which sets it apart from inspect_document. This is a clear, non-tautological purpose statement.

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 description provides explicit when-to-use ('what's in this folder?' before selecting analysis targets) and when-not-to-use (when page count or title structure is needed → inspect_document). It also gives a conditional routing rule: if expected_grade is 'B?', use inspect_document. This is comprehensive usage guidance with named alternatives.

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