get_data_registry_item

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, non-open-world), so the bar is lower, and the description still adds real value: synchronous execution, the exact underlying API, the precache prerequisite, and that an uncached item yields a clean error rather than a failure. It does not discuss performance, cost, or whether reading refreshes/loads anything.

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, then the precache constraint, then the error behavior, and finally the return shape. The UDataRegistrySubsystem::GetCachedItemRaw reference is engine-facing detail that a calling agent can't act on, which is the only real waste.

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, listing the returned fields (registry_type, item_name, item_struct, found, item_data) is necessary and present. Preconditions and error semantics are covered too; the gap is that the agent isn't pointed at how to enumerate valid registry types or how to make a source precached before calling.

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 self-describing enough that the baseline of 3 applies. The description adds only the notion that item_name is a registry 'row' and that the pair must resolve to a precached entry; it gives no format, case-sensitivity, or validity rules for registry_type beyond what the schema says.

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 gives a specific verb and resource ('Synchronously look up a precached item by registry type and item name') and names the underlying API, UDataRegistrySubsystem::GetCachedItemRaw. It scopes the tool to precached sources, which separates it from cache-mutating siblings, but it never names a sibling tool explicitly (e.g. initialize_data_registry, refresh_data_registry_map).

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?

It states the precondition clearly ('the registry must be initialized first') and the eligibility constraint ('Only returns data for items backed by a precached source'), plus the failure behavior if the item is not cached. What's missing is explicit routing: the agent is not told to call initialize_data_registry or refresh_data_registry_map first, nor when to prefer list_data_registry_types for discovering valid registry_type values.

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