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

Annotations already declare destructive=true, idempotent=false, openWorld=true, so the safety bar is partly met; the description adds real value by clarifying that the move applies to existing bookings including an unsent retry, and that no further decision is needed afterward. The retry guidance for a lost reply and the post-refusal read-the-task instruction are behaviors no annotation conveys. It does not describe what state is destroyed or confirm the revision conflict failure mode in detail, so not a 5.

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?

Front-loaded with the core action, which is good, but the middle sentences are dense and jargon-heavy ('Listed hours and contactAdvice are guidance under advisory timing'), referencing domain concepts an agent must already know. Several clauses are load-bearing, but the phrasing could be tightened considerably.

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 an output schema present, return values need no explanation, and annotations cover the risk profile. The description fills the remaining gap that matters most for a destructive, non-idempotent mutation: retry semantics on a lost reply and the required follow-up after a refusal. It leaves the ownership/permission path only implicitly covered, so 4.

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 all five parameters including when, callId, expectedRevision and ownerConfirmation are already documented. The description only restates the startWindow-vs-allowed selection that the 'when' schema describes, adding no new syntax or format meaning. 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?

States a specific verb and resource: 'Move a call that is already booked, or call now.' It also scopes the operation to an existing booking rather than creating one, which separates it from prepare_task/approve_call style siblings. It does not explicitly name a sibling tool, so it stops short of a 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?

Gives clear triggering conditions ('on the owner's request or under Let the agent decide') and selection logic between nextCall.startWindow and nextCall.allowed. It also prescribes recovery behavior ('after refusal read the task; after a lost reply repeat identical arguments'). No explicit when-not or named alternative tool, so 4 rather than 5.

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