list_directory

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description contributes one genuinely useful behavioral fact beyond that — sandboxing to the home directory — which constrains what paths will work. It says nothing about hidden files, sorting, symlinks, or error behavior on a missing path.

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?

A single sentence with zero padding; the core action comes first and the sandbox constraint follows. Nothing to trim and nothing 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 two-parameter read-only listing tool with full schema coverage and annotations, the key operational constraint (home-directory sandbox) is stated. The only remaining gap is the shape of the returned listing, which matters slightly more since no output schema exists, but the tool's nature makes it largely self-evident.

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%, including a description for the optional `details` flag, so the schema already carries full parameter meaning. The description mentions only the path concept and adds no syntax or format detail beyond the schema. Baseline 3 applies when the schema does all the work.

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?

A specific verb ("List") plus resource ("files and directories at a path") that clearly separates it from siblings like read_file and file_info, which operate on a single file's contents. The parenthetical adds the operating scope. It stops short of naming a sibling alternative, but the verb/resource pairing is unambiguous.

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?

Usage is only implied: "at a path" signals directory exploration, and the sibling read_file covers file contents, but the description never states when to prefer this over read_file or file_info, nor any exclusions. An agent can infer the use case but gets no explicit routing guidance.

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