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

With readOnlyHint and openWorldHint already declared, the description adds genuine non-schema context: the call is free, and the response includes current follower and view numbers plus the user's collections. That tells the agent what kind of data comes back and that there is no cost barrier, going beyond the annotations, though it says nothing about pagination, freshness/staleness of the numbers, or auth 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?

The core action and scope are front-loaded in the first clause, and the trailing fragments ('Free', 'Good for...') each carry distinct information without padding. It is compact and readable, losing only a little on the choppy fragment style.

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 two-parameter read-only tool with no output schema, the description covers what is listed, the filtering options, the returned fields, and the cost signal, which is close to sufficient for correct invocation. The remaining gap is the undocumented 'limit' parameter and any statement of pagination behavior.

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 50%: the 'collection' parameter is documented in the schema, while 'limit' has no description anywhere. The description's '(all, or one collection by name or id)' largely restates the collection schema text rather than adding syntax or behavior, and it leaves the limit/pagination semantics unexplained, so it only partially compensates 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?

It names a specific verb and resource ('List the user's saved creators') and scopes it to 'all, or one collection by name or id', which cleanly separates it from siblings like search_creators and lookup_creators that don't operate on the saved list. It stops short of naming those siblings explicitly, so an agent must infer the boundary from the word 'saved'.

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?

'Good for building a shortlist, a report or a spreadsheet' hints at intended use cases, and 'Free' signals cost, which is relevant when choosing between this and heavier search tools. However, it never states when NOT to use it or points to an alternative such as search_creators when the user has not saved anything yet, leaving the routing decision to inference.

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