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

Annotations already declare readOnlyHint, idempotentHint, and nondestructive behavior; the description adds quota info ('FREE — does not consume quota') and explains the different item representations returned per folder type (ids, hub profiles, domains). No contradiction with annotations.

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 description is dense but not bloated: it states the return shape, both parameter modes, the recommended use, and the quota effect in about four sentences. Every sentence carries operational value.

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?

Given the output schema and rich annotations, the description still adds enough to call the tool confidently: return fields for the folder list, exact item-return behavior for the folder parameter, how to disambiguate duplicate names, and quota impact. No important operational gap remains.

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 the schema already documents both parameters fully; the description largely restates the same mode information and even the disambiguation caveat ('pass entity_type to disambiguate') that appears in the schema. It adds a little value by tying ids to get_creative/get_webmaster/get_ad, but does not substantially extend the schema.

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?

The description opens with a specific verb and resource, 'List the caller's favourites folders (name, entity_type, item_count)', and then clarifies the two modes: folder listing and folder contents. It also names the related tool add_to_favorites, so an agent can see how this read operation fits.

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?

It gives explicit instructions about when to omit entity_type (all folders), when to pass it (filter), and when to pass folder (return items). It also states the purpose: 'Use this to confirm what add_to_favorites saved and to read a folder back.' It does not mention explicit exclusions, but no sibling tool overlaps directly with favourites.

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