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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so safety is covered. The description adds genuine behavioral context beyond that: it explains the two branches of behavior (returns services if already streaming, otherwise a predicted date from historical gaps with a confidence level) and that an alert-setup link is returned. It stops short of noting auth needs or prediction caveats/error cases, 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?

The definition is front-loaded with the use case in the opening sentence, then covers return behavior, then the sibling routing rule. Each sentence earns its place, though the quoted-question opener and the compound second sentence are slightly dense rather than maximally tight.

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 no output schema, the description carries the return-value burden well: it explains both outcome branches (services vs. predicted date with confidence), the alert link, and the market scope. Combined with annotations covering the safety profile and a fully-described 2-parameter schema, an agent has everything needed to call this 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% — both title and country (with ISO examples and the IN default) are documented in the schema. The description only alludes to them implicitly, adding no format or edge-case detail beyond the schema, 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 names the exact question it answers ('when is <movie> coming to OTT / Netflix / Prime in <country>') and scopes it to OTTASIA's Asian, Middle Eastern and diaspora markets. It clearly distinguishes itself from where_to_watch by framing itself as the 'WHEN' tool rather than the availability tool.

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 final line gives an explicit routing rule: 'Use where_to_watch for plain availability questions; use this when the user asks WHEN.' This names the alternative tool and the exact condition that selects it, leaving nothing to inference.

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