file.append

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

Without annotations, the description provides behavioral context: it is cheap and does not require reading existing content. It also indicates it creates the file if missing. No contradictions.

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 extremely concise at two sentences, front-loading the core purpose and a key behavioral trait. No unnecessary 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 5 parameters, no parameter descriptions, and no output schema, the description is incomplete. It does not cover important context like the purpose of 'vault', 'dry_run', or 'ensureTrailingNewline', which could lead to misuse.

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 description only indirectly references the 'content' and 'file' parameters but does not explain 'vault', 'dry_run', or 'ensureTrailingNewline'. With 0% schema coverage, the description fails to compensate, leaving key parameters underspecified.

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 clearly states the action (append text to a file) and includes the additional behavior of creating the file if missing, which distinguishes it from siblings like file.create or file.replace.

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?

It suggests when to use this tool by noting it's 'cheap' and requires no read, implying it's preferred for simple appends without prior content checks. However, it does not explicitly contrast with alternatives or specify when not to use.

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