ap_fs_stat

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. The wording 'Report whether' clearly frames the tool as an inspection/read operation with no side effects, and enumerates exactly what is tested. It does not cover error handling or permissions, but for a simple stat query this is reasonably transparent.

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 a single, focused sentence with no filler. It front-loads the action and immediately lists the exact facts reported, making it easy for an agent to scan and understand.

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?

The tool is simple with one parameter and no output schema. The description adequately conveys what the tool will tell the caller. It could mention the return shape or error behavior, but these are minor gaps for a stat-like operation.

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%, and the schema already explains that the path must be absolute and use forward slashes. The description does not add significant new meaning to the 'path' parameter beyond restating the tool's purpose, so the baseline score of 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 uses a specific verb ('Report') and resource ('path'), and clearly defines the three checks performed: existence, directory status, and absoluteness. This clearly differentiates it from sibling filesystem tools like ap_fs_list and ap_fs_mkdir.

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 implies when to use the tool—when path properties need to be verified—but it does not explicitly state alternatives or exclusions. There is no guidance like 'use ap_fs_list for listing directory contents' or 'prefer this before creating files.'

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