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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=true), so the description's job is to add what annotations cannot. It does: partial-success semantics (failing files come back in `rejected` with key and error) and deferred application ('the rest apply at the next restart'), which is critical behavior an agent cannot infer. It stops short of saying whether a partially-rejected batch leaves orphaned uploads or whether rejected entries need re-uploading.

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?

A single dense sentence ordered by importance: what it does, the cap, the alternative route, then the result contract. No filler, nothing repeated from annotations.

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 mutating, multi-file completion step with no output schema, the description covers the failure channel and apply timing, which are the two things an agent most needs. Minor gaps remain around atomicity and whether a restart is required versus automatic, but the essential call contract is present.

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?

Coverage is reported at 0% for the two top-level parameters (`body`, `path`), so the description should compensate but largely does not — it never explains serverId or the uploads array. It adds two useful facts beyond the schema (the 50-file cap and that rejected results echo the `key`), but the nested shape of parts/uploadId is left entirely to the schema's own field descriptions.

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 — installs uploaded files, up to 50 — and names both its prerequisite (startAssetUpload) and the sibling that handles a special case (setResourcePack for resource packs). An agent can tell it apart from completeWorldUpload/completeModpackUpload and from its abort counterpart without opening a schema.

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 encodes the calling sequence ('files from startAssetUpload calls') and routes resource packs to a different sibling. This is exactly the when-to-use / when-to-use-something-else information an agent needs, delivered in one clause.

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