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

Annotations already declare readOnlyHint=true and openWorldHint=false, but the description adds substantive behavior: result ordering, empty-collection vs unknown/inaccessible-collection outcomes (empty list vs error), and side effects (usage counting and activity-log visibility). This is exactly the context annotations cannot convey.

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?

Four compact sentences, front-loaded with purpose and ordering, then pagination, then edge-case outcomes, then side effects. No sentence is 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?

No output schema exists, so the description carries return-shape burden; it implies a list of saved posts ordered newest-first but does not enumerate fields. For a simple read-only list tool this is close to sufficient, with only minor gaps.

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 limits and offsets are already documented. The description still adds meaning by tying collection_id to list_collections and confirming pagination semantics and default ordering, which the schema does not state.

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 ('List saved posts from one collection'), scopes it to the authenticated user's library, and specifies ordering ('newest imports first'). An agent can immediately distinguish this from get_save, recent_saves, and search_saves.

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 directs the agent to obtain collection_id from list_collections, giving clear prerequisite context. It does not explicitly say when to prefer recent_saves or search_saves over this tool, so sibling routing is left partly implicit.

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