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

Annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=false, so the write profile is known. The description adds genuinely non-obvious behavior that annotations cannot convey: the call returns upload_url and blob_key, and the actual archive PUT goes straight to storage outside this interface, with complete_upload required for visibility. That is strong added context, though nothing is said about failure modes or what happens to a project left incomplete.

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?

Three tight sentences front-loading the action, then the return values, then the mandatory next step in causal order. The opening sentence merely restates the title, but everything after it is load-bearing and there is no filler.

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 correctly compensates by naming the two returned fields and explaining the two-phase upload. For a two-parameter creation tool with explicit annotations, the missing piece is only the semantics of idempotency_key and what happens if complete_upload is never called.

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 description carries the full burden, yet it explains neither parameter. The purpose of idempotency_key — the one parameter whose semantics are genuinely non-obvious — is left entirely undocumented, and the annotations even say idempotentHint=false, which makes its role more, not less, confusing.

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?

"Create a project" gives a specific verb and resource, and the follow-on sentences clarify what the call actually produces (upload_url, blob_key) rather than just a project record. It never contrasts itself with create_service or the list/get siblings, so an agent must infer placement from naming 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 description gives a clear mandatory follow-up: after uploading the archive, complete_upload must be called or the upload is invisible to the platform. That is real workflow routing to a named sibling. It stops short of stating when to create a project versus an alternative path (e.g., create_service), and no prerequisites or permissions are mentioned.

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