list_tree

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 the contextual detail 'Free local I/O,' which hints at non-destructive, local behavior, but it does not explicitly state that the operation is read-only or non-mutating. It also does not mention error conditions, permission requirements, or what happens to inaccessible directories. The phrase is helpful but leaves room for ambiguity in a tool that could touch the filesystem.

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 two sentences: the first states the core purpose, the second provides a crucial usage note. Every word adds value. It is front-loaded with the most important information and does not waste tokens on redundant details.

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?

Given the tool's moderate complexity (6 parameters, no output schema, no annotations), the description covers the primary context: what it does and when to prefer it. It could elaborate on the output format (e.g., how entries are sorted or truncated), but the combination of a clear schema and a concise description is largely complete for most usage scenarios. The missing output details slightly lower the score from a 5.

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% (all 6 parameters have descriptions). Per the rubric, when coverage is high, the baseline is 3. The description adds no additional parameter semantics beyond the schema, which is acceptable given the schema already documents each field (e.g., 'path', 'depth', 'max_entries').

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 lists directory structure under a path within a project root: 'List the directory structure under a path inside a project root.' It uses a specific verb ('List') and resource ('directory structure'), and immediately differentiates from the sibling tool by stating 'prefer over deep_explore for any directory layout question.' This directly addresses purpose and provides sibling distinction.

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 explicitly names an alternative sibling tool ('deep_explore') and gives a clear usage recommendation: 'prefer over deep_explore for any directory layout question.' This is an explicit 'use this instead' guidance, matching the calibration example that earned a 5. It tells the agent when to choose this tool over a known alternative.

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