list_folder

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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), so the bar is lower. The description still adds the genuinely useful state requirement that the vault must be open, and names what the result contains; it does not need to explain returns since an output schema exists.

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?

Two compact sentences: the operation and its result are front-loaded, then the one parameter whose syntax is non-obvious. Nothing is wasted and nothing important is buried.

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 read-only, two-parameter listing tool with a 100%-covered schema and an output schema, the description covers purpose, output content and the open-vault precondition. The only missing element is routing guidance relative to siblings such as find or file_info.

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 description coverage is 100%, so vault and folder are both fully documented in the schema. The description's restatement of the folder path format and the '/' convention duplicates the schema rather than adding new meaning, so the baseline 3 applies.

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 gives a specific verb (List) and resource (a folder), and further specifies the payload an agent will get back: names, kinds and sizes. That is enough to separate it from read_file or find in practice, though it never names a sibling tool to contrast against, which keeps it short of a 5.

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 phrase 'in an open vault' implies the vault must already be unlocked, which is a real usage precondition, but the description never says when to prefer this over find, file_info or locate. Usage is only implied, not stated.

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