vault_append_to_file

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 key behavioral traits: the tool appends content, creates the file if it doesn't exist, and doesn't replace existing content. However, it lacks details on permissions, rate limits, error handling, or response format, which are important 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 front-loaded with the core purpose in the first sentence, followed by conditional behavior and usage guidance. Every sentence adds value without redundancy, making it efficient and easy to parse for an AI agent.

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 no annotations, no output schema, and a mutation tool with 0 parameters, the description covers the basic operation and usage well. However, it lacks details on return values, error cases, or side effects, which would enhance completeness for a tool that modifies files.

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 input schema has 0 parameters with 100% coverage, so no parameters need documentation. The description adds context about the tool's behavior regarding file existence and content handling, which compensates for the lack of parameter details. Baseline is 4 for 0 parameters, as it provides useful operational context.

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 content to the end of an existing file') and the resource ('file'), distinguishing it from siblings like vault_create_file (creates new), vault_delete_file (removes), vault_patch_file (modifies), and vault_get_file (reads). The phrase 'without replacing existing content' further differentiates it from overwrite operations.

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 explicitly states when to use this tool ('Use this to add content without replacing existing content') and provides a clear alternative scenario ('If the file doesn't exist, it will be created'), which distinguishes it from vault_create_file for new files. It also implies when not to use it (e.g., for overwriting or reading files).

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