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

Annotations already flag destructiveHint=true and readOnlyHint=false, so the write/destroy profile is covered. The description adds genuinely new behavioral context the annotations cannot express: a plan entitlement gate ('Pro plan only') and the side effect that shared links survive the replacement, which is the main risk consideration for an agent.

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 tight sentences; the plan restriction is front-loaded, then the effect on links, then the fallback. Nothing is repeated or padded.

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 3-parameter mutation tool with full annotation coverage and full schema coverage, it supplies the non-obvious constraints (plan tier, link stability). It does not mention what the call returns, but no output schema exists and the return is not essential to calling it correctly.

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% and every parameter, including the optional file_name with its 'omit to keep current name' guidance, is documented in the schema itself. The description adds no parameter-level detail beyond that, so the baseline 3 applies.

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 and resource ('Replaces the content of an existing file') and adds the distinguishing trait that the public link is preserved. That differentiates it in effect from upload_file and publish_document, though those siblings are never named, so the routing is implicit rather than explicit.

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 gives a clear when-to-use condition (Pro plan, existing file, link must keep working) and an explicit when-not/alternative path for Free plan users ('publish a new file instead'). The gap is that the alternative is described as an action rather than pointed at a concrete sibling tool such as publish_document or upload_file.

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