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

No annotations are provided, so the description carries the full behavioral burden. Labelling it a PATCH usefully implies partial update semantics (only supplied fields change), but it says nothing about authentication needs, whether an empty call is a no-op, what happens to fields omitted, or what the response contains — all material for a mutation tool with zero annotation coverage.

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, zero waste, with the field list and the PATCH semantics front-loaded before the disambiguation clause. Dense but every clause carries routing or scoping 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?

There is no output schema and no annotations, and the schema has eight parameters at 13% coverage with an empty required list — a genuinely ambiguous call shape. The description covers the intent and sibling routing well but leaves the agent without guidance on localization_id, empty-payload behavior, or what the mutation returns, which is a meaningful gap for this complexity.

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 only 13%, so the description must compensate, and it does partially: it names six of the seven updateable payload fields, mapping them to the schema properties. However it never explains localization_id (how it is obtained, whether it is effectively mandatory given an empty required list, and whether omitting it fans out across all localizations), and it ignores notification_message entirely.

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?

Starts with a specific verb ("Update") and scopes the resource precisely to the current app store version's localization, enumerating the six copy fields it touches and naming the underlying PATCH endpoint. It explicitly disambiguates from the app-level sibling update_app_info_localization, so an agent can pick the right tool from the name+description alone.

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 second sentence gives an explicit when-to-use ("App Store listing copy tied to a specific version") and an explicit when-not-to-use with the named alternative ("not app-level info (see update_app_info_localization)"). That is a complete routing rule rather than an implied one.

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