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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds useful content scope (metadata plus current single-country offers, contrasted with title_offers across countries), but says nothing about rate limits, caching, auth, or freshness. With annotations carrying the behavioral load, this is a modest but real addition.

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 core action, with the routing guidance following. No filler; every clause adds information.

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?

An output schema exists, so return values need not be described, and annotations cover the read-only profile. The one gap is the crowded justwatch_title_* sibling space, where an agent might still confuse this with title_by_id; the description could have closed that off in a clause.

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 coverage is 100% and both parameters are fully documented in-schema, including the 'pass exactly one of path or url' constraint. The description only restates the accepted input forms, adding no syntax or format 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?

States a specific verb (fetch) and resource (JustWatch title record) plus its scope (metadata and current offers) and the accepted input forms (canonical path or URL). It implicitly separates itself from justwatch_title_by_id by specifying path/URL input, but it never names that sibling, so differentiation from the other title_* tools is only partial.

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?

Explicitly routes the agent: use justwatch_search to obtain the canonical reference, and justwatch_title_offers for multi-country offers. That covers the two most likely wrong turns, though it gives no exclusions relative to justwatch_title_by_id, title_analysis, or title_media.

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