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

Beyond the annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=false), the description adds genuinely useful context: this is a cancellation rather than a deletion, the reply reverts to draft rather than vanishing, and a plan plus write-scoped credential is required. It stops short of saying what happens on a non-scheduled or already-posted reply, and it does not acknowledge the non-idempotent behavior the annotations flag.

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?

One dense sentence with the operation class ('WRITE tool') front-loaded, followed by the effect, then the prerequisites. No filler and nothing buried.

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 one-parameter, no-output-schema tool, the description covers what it does, the resulting state, and the access requirements. The only real gap is edge-case behavior when the reply is not currently scheduled.

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?

There is a single parameter with 100% schema description coverage, and the schema already explains that review_id is a Sonar review id from sonar_review_inbox rather than Apple's id. The description adds no further parameter guidance, so the baseline of 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 gives a specific verb and resource ('cancel a scheduled reply') and even specifies the state transition ('it goes back to draft'), which cleanly separates it from sonar_post_review_reply and sonar_draft_review_reply in effect. It never explicitly names a sibling tool, so it falls just short of the top band.

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 timing condition 'before it posts' tells the agent when the tool applies, and the entry conditions (Indie plan, authorized account or write-scoped API key) are stated outright. What is missing is an explicit exclusion, e.g. what to use if the reply has already been posted, or how it differs from dismiss_review_reply.

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