append_file

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

With no annotations present, the description carries the full burden and does reasonably well: it discloses two failure modes (nonexistent file, exceeding max file size) and the return payload (path plus byte count). It omits encoding, whether parent directories must exist, and atomicity/concurrency behavior, but the core mutation semantics are clear.

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?

Front-loads the purpose in one sentence, then uses terse Args/Returns blocks where every line adds information. Slightly more formatting scaffolding than a single sentence needs, but nothing is wasted.

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 mutation tool with no annotations and no output schema, the description covers the action, both parameters, the return value, and the two documented failure conditions. Remaining gaps (encoding, directory prerequisites) are minor.

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 0%, so the description must compensate, and it does: 'path' is documented as relative to the workspace root and required to exist, and 'content' as the text to append. Both parameters gain meaning beyond the bare string types in 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?

States a specific verb (append) and resource (text to an existing file) plus scope ('inside the workspace'). The 'existing file' qualifier and the explicit 'fails if the file does not exist' distinguish it from the sibling write_file, which creates/overwrites.

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?

Usage is implied by the purpose and the 'existing file' constraint, but the description never states when to choose this over write_file or how to handle a missing file (create it first, use write_file, etc.). No explicit when/when-not guidance is given.

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