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

Annotations already declare the write and destructive nature, while the description adds important behavior: writes are atomic compare-and-swap, a null expected hash means creation only, and a save step is required afterward. It does not explain partial failure behavior or permission requirements, but it adds meaningful context beyond annotations.

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 very compact and front-loads the core atomic CAS behavior. It uses terse semicolon fragments, but there is no filler or repetition.

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?

This is a destructive batch write tool with three required parameters, a nested file array, CAS semantics, and no output schema. The description covers only the atomic write and create-on-null aspects, leaving key operational details such as batch limits, required save target, and failure behavior unexplained.

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 carry parameter meaning. "null creates only" usefully explains expected_sha256, but workspace, build_id, path, content, and the file array constraints remain undocumented in both schema descriptions and the text.

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 names the operation as atomic CAS writes and clarifies null creates only, but relies on jargon and does not explicitly state that it writes build files or how it differs from files_edit. The purpose is inferable from the tool name and title, not fully from the description itself.

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?

"Save afterward" is the only procedural guidance and is ambiguous about which save operation is required. The description does not say when to use this instead of files_edit, files_delete, or builds_save.

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