list_rootsLists the directories this server can access as absolute paths, including any granted during the session. Use it to identify available filesystem roots before working with files.
List the directories this server can access, as absolute paths, including any the user granted during this session. Other tools can ask the user to grant access to a path outside them.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v2.4.1Input schema / $schemaAdded value: +"https://json-schema.org/draft/2020-12/schema"v2.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds useful context beyond that: results are absolute paths and include any directories granted during the current session. This helps the agent understand what the returned set represents.
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 sentences with no filler. The core behavior is stated first, and the companion behavior about other tools granting access is a useful one-line addition. Every sentence earns its place.
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 zero-parameter listing tool, the description fully explains what is returned (absolute paths of accessible directories), the session-grant aspect, and how it relates to other tools. No output schema is present, but the return concept is simple and clearly stated.
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 parametersasi, so the schema cannot provide parameter detail. With no parameters to document, the baseline of 4 applies; the description fully clarifies what the tool returns without needing parameter semantics.
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') with a clear resource ('directories this server can access, as absolute paths'). It distinguishes list_roots from the generic sibling 'list' by scoping it to server-accessible workspace roots, including session-granted paths.
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 makes it clear this tool is for discovering accessible directories. It also notes that other tools can request access to paths outside these roots, giving the agent a hint about when this tool is not sufficient. It does not explicitly name alternatives, but the context is clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.