Inventory approved roots

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

Annotations already indicate readOnlyHint=true, and the description adds the meaningful constraint 'Does not scan file contents,' which clarifies that the tool only returns directory paths and does not inspect contents. This goes beyond the annotation's read-only flag by describing operational scope, adding genuine value.

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 and directly conveys the tool's purpose and limitation. Every word serves a distinct function: it states the action ('List'), the object ('directories'), the scope ('explicitly configured'), and the non-behavior ('Does not scan file contents'). No waste or redundancy.

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 simplicity—no parameters, no output schema, and a single clear function—the description fully covers what an agent needs: what the tool returns (root directories) and what it does not do (scan contents). The sibling tools suggest broader analysis, so this narrow scope is appropriately complete.

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 tool has zero parameters, so there is no parameter burden on the description. The baseline for no parameters is 4, and the description does not need to add extra parameter details. It correctly focuses on the tool's behavior rather than parameter explanations.

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 uses a specific verb ('List') and clearly identifies the resource ('explicitly configured directories this server is allowed to inspect'). It distinguishes itself from sibling tools like summarize_project and analyze_project by focusing on allowed inspection roots rather than content analysis.

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 clear context for when to use the tool: to list approved root directories. It also notes the limitation 'Does not scan file contents,' implying use only when directory names are needed, not file-level inspection. However, it does not explicitly name alternatives or exclude specific use cases, so it falls short of a 5.

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