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

Annotations already cover the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=true), so the bar is lower. The description still adds real value beyond them: partial-update semantics for omitted fields, and the side effect that is_public=true returns a public URL while false revokes it. It does not explain what makes the operation "destructive" (i.e., that supplied values overwrite existing ones) or any permission requirements.

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 tightly written sentences, front-loaded with the mutation scope and followed by the two pieces of guidance an agent most needs. The is_public clause partially restates the schema description, but nothing is padded.

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 nine-parameter partial-update tool with annotations present and no output schema, the description covers the essentials: what can change, that omissions are preserved, and the sharing side effect with its return value. An agent has enough to call this correctly without further context.

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%, so all nine parameters including color, reason, and budget_currency are already documented in the schema, making 3 the correct baseline. The description adds a little meaning for is_public (URL generation on true, unshare on false), but the other fields get no detail beyond their names.

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?

Opens with a specific verb+resource ("Update a collection") and enumerates the mutable fields, so an agent knows exactly what this tool changes versus siblings like create_collection or delete_collection. It stops short of explicitly contrasting itself with sibling tools, but the scope is unambiguous.

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 patch guidance ("Only provide the fields you want to change — omitted fields stay unchanged") tells the agent how to call it, and the is_public note explains when to set true vs false. However, there is no guidance on when to prefer this over alternatives such as update_item or set_pinned_items, and no prerequisites are stated.

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