create_instance

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

With no annotations, the description carries the full burden and does real work: it discloses that only two config files are written, that Prism lazily resolves the rest on first launch, and that loader builds come from the meta API with a recommended-build default. It lacks failure-mode or permission/response information, which keeps it short of 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?

Two tight sentences, both front-loaded with the operative fact (what gets written, how loader versions are resolved). No filler or restatement of the tool name.

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?

For a six-parameter mutation tool with no annotations, no output schema, and 0% schema coverage, the description covers side effects and defaulting well but omits parameter semantics for four fields, error/precondition behavior, and any hint of the return value.

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% for all six parameters, so the description must compensate and only partially does: it explains mcVersion and loaderVersion behavior (recommended build unless overridden). The meaning of name, group, loader, and iconKey is left entirely undocumented, including what loader values are accepted.

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 ("Create an instance") and goes further by naming the artifacts it writes (instance.cfg + mmc-pack.json). It does not distinguish itself from siblings that also produce instances (clone_instance, import_modpack), so the agent must infer the boundary.

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?

Creating a new instance is self-evidently the use case, so usage is implied, but there is no explicit when-to-use vs. clone_instance/import_modpack guidance and no mention of preconditions (e.g., name collisions, valid loader values).

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