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

Annotations already declare readOnlyHint=false, destructiveHint=true and idempotentHint=true, so the safety profile is carried by structured data. The description adds the important scope limit that stored reply text is untouched, clarifying what the 'destructive' flag actually applies to. It does not explain the idempotent or open-world implications, so it is not exhaustive.

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 body is a single dense sentence with the core behavior front-loaded. The leading 'Mark Review Replied' heading merely repeats the title and consumes space without adding information, which is the only real waste.

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?

With a full output schema and rich annotations, the description only needs to convey the operation's intent and scope, which it does. Nothing critical is missing for an agent to call it correctly, though naming the counterpart tool for in-platform replies would make it fully self-sufficient.

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 both parameters are already documented, including the true/false semantics of 'replied'. The description's 'set or clear replied_at' restates that mapping rather than adding syntax or edge-case detail. Baseline 3 is correct when the schema does the heavy lifting.

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 a specific operation (set or clear replied_at) on a specific resource (review reply state) and adds the key qualifier 'without changing stored reply text', which separates it from the sibling updateReviewIntegrationReply. It stops short of naming that sibling explicitly, so it is clear but not fully disambiguating.

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 states the trigger condition plainly: use this 'when a reply was handled outside the platform'. That is a real when-to-use cue rather than an implied one. It does not name the alternative tool to use when the reply was made through the platform, so the routing guidance is incomplete but usable.

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