file_exists

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

With no annotations provided, the description carries the full burden. It discloses that the tool checks both files and directories and returns a boolean, which covers the core behavior. However, it does not mention edge cases like symlinks, permission errors, or whether the path must be normalized, leaving some behavioral gaps.

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 concise with two sentences followed by a bilingual translation. The English part is front-loaded and efficient, though the Chinese duplicate adds slight redundancy. Overall, it is appropriately sized with no wasted words.

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 simple nature of the tool (one parameter, boolean output schema), the description adequately covers the input, output behavior, and a usage context. No further details are strictly necessary for an agent to use this tool correctly.

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 schema description covers 100% of the parameter with examples and a clear definition. The description only repeats 'specified path' without adding additional semantics, so it meets the baseline but adds no extra value beyond the schema.

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 'Check if' with an explicit resource 'file or directory' and path parameter. It clearly states the return value (true/false) and distinguishes itself from siblings by focusing solely on existence checking, unlike file_stat or search_files.

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 phrase 'Useful for conditional operations' provides some context for when to use the tool, but it does not explicitly mention alternatives or when not to use it. Sibling tools like file_stat could potentially serve similar purposes, and no exclusions are given.

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