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

Annotations already declare readOnlyHint=false, destructiveHint=false and idempotentHint=false, so the safety profile is largely covered. The description nonetheless adds genuine context beyond them: earlier versions remain available (so the write is additive, not replacing history) and the caller must own or have edit rights. Response shape and size limits are still unmentioned.

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?

Two short sentences, with the core action front-loaded and the non-destructive versioning guarantee immediately after. Nothing is padding.

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 4-parameter mutation with full schema coverage, safety annotations, and no output schema, the description covers the essentials: what it does, the permission prerequisite, and version retention. The only gap is what the call returns (e.g. a new version identifier), which an agent would have to discover empirically.

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 fileId, contentBase64, name and mime are fully documented in the schema itself. The description adds no format, size, or naming guidance beyond that, which matches the baseline 3 for schema-covered parameters.

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+resource: 'Upload a new version of a file'. That contrasts implicitly with files_upload (a new file) and files_versions (version history), so an agent can distinguish the operation. It stops short of naming those siblings explicitly, which keeps it at 4 rather than 5.

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 phrase 'a file you own or may edit' gives a real permission precondition for choosing this tool. However, it never states when to prefer this over files_upload or files_versions, so the alternative-selection guidance is only implied.

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