append_file

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

There are no annotations, so the description carries the full behavioral burden. It does disclose an important side effect: the file is created if missing. However, it does not mention permissions, error conditions, whether parent directories are created, or the return value, which are relevant for a mutation tool.

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 short sentences with no redundant words. The core action 'Append content to file' is front-loaded, and the edge case behavior 'Creates if missing' is a valuable addition without bloat.

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 simple two-parameter tool, the description covers the essential behavior and the missing-file case. Still, it omits failure modes, permission requirements, and whether the operation returns anything, which an agent may need when invoking the tool safely in a filesystem context.

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%, so the parameters path and content are already fully described by the schema. The description does not add param-specific meaning beyond confirming the content is appended, so the baseline score of 3 is appropriate.

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 states a specific verb and resource: 'Append content to file.' This clearly distinguishes it from the sibling write_file (which overwrites) and read_file (which reads). The additional note 'Creates if missing' confirms its purpose for both existing and new 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 description implies the usage context: use this tool when content should be added to a file, and it can create the file if absent. However, it does not explicitly contrast with write_file or state when not to use this tool, leaving the boundary to inference.

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