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

Annotations already declare idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral constraints beyond that: only *pending* calls can be moved, and the target time is bounded to 'within the next year.' It doesn't describe error behavior (e.g. completed or cancelled calls) but the added constraints are meaningful.

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 sentences, front-loaded with the action and its scope, then the identification methods, then the alternative. Every clause carries information; no filler.

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 tool with no output schema, the description covers what moves, how to identify the target, the time bound, and the alternative tool. A note on precedence among the three identifiers or on non-pending calls would close the remaining gap, but nothing essential is missing.

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 four parameters (lead_id, phone_number, scheduled_at, scheduled_call_id) are already documented in the schema, including the ISO 8601 offset/timezone rule. The description restates the identification options without adding format or precedence semantics (e.g. what happens if both lead_id and scheduled_call_id are supplied). Baseline 3 is appropriate.

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 with scope: 'Move a lead's pending scheduled call (a booked callback or the next follow-up) to a new time.' The parenthetical clarifies exactly what a 'scheduled call' is, and it explicitly contrasts itself with the sibling schedule_call, so an agent can pick it without opening schemas.

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 explicit routing: use this when a call is pending, use schedule_call when the lead has none. It also spells out the three accepted identification paths (scheduled_call_id, lead_id, phone_number). The only gap is that it doesn't explicitly distinguish itself from cancel_scheduled_call or update_schedule, but the alternative-and-condition pattern is fully present.

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