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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds real behavioral value by disclosing the closed-world constraint (only public mods are visible) and the error-on-unknown-ID behavior. It says nothing about response shape, pagination, or whether unpublished/private mods are indistinguishable from nonexistent ones.

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 short sentences, front-loaded with the core action, and no filler. The phrase "supported scope and limitations" is vague enough to cost a point because a reader cannot tell whether it means game compatibility, feature limits, or both.

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 burden of describing the payload, and it names the returned facets only vaguely. It omits the id format and any notion of what a successful response contains, though the error semantics it does state are helpful for a read tool.

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 0%, so the only structured hint about the single parameter is a regex pattern (^[a-z][a-z0-9-]{0,47}$). The description does not explain that id is a lowercase mod slug, how to obtain it, or its length limit, so it fails to compensate for the coverage gap.

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 ("Read a public mod description") plus the facets returned (scope and limitations), which separates it from siblings like search_catalog and get_compatibility_guidance. It stops short of explicitly naming the boundary against those siblings.

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?

There is no explicit when-to-use guidance and no routing to alternatives; an agent must infer that get_mod_details is the follow-up to a search_catalog result. The only usage-adjacent information is the failure note that unknown IDs return an error.

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