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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=true), so the bar is lower, but the description still adds real value: it discloses that saving unlocks the creator at 0.5 credits the first time and is free on repeat, which is a concrete cost side-effect an agent must know before calling. The consistency with idempotentHint=true is good; only error/duplicate handling is left unstated.

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-loaded with the action and destination before the cost and parameter advice. The parenthetical "(the dashboard's Saved page)" is slightly clunky but earns its place by anchoring the concept to a UI surface the user knows.

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 mutation with full schema coverage and no output schema, the description covers the essential unknowns: what the saved list is, that it sits outside campaigns, the credit cost, and free repeat saves. Only duplicate-handling and the response shape are absent, which is minor given the annotations.

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 both parameters are documented in the schema already. The description adds modest meaning by framing searchId as provenance ("remember where they were found") rather than just a filter id, but creatorId gets no extra semantics beyond the schema's own pointer to search_creators results.

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 states a specific verb and resource ("Saves a creator to the account's saved list") and scopes it precisely as the user's own bookmarks outside any campaign, to the dashboard's Saved page. That separates it from campaign-oriented siblings in spirit, but it never names add_creator or unlock_creator explicitly, which is the main ambiguity for an agent choosing among the three.

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 implies when to use the tool by defining the saved-list destination and by noting the credit cost, and it gives one concrete usage instruction (pass searchId to remember where the creator was found). It stops short of saying when to prefer this over add_creator or unlock_creator, or what happens if the creator is already saved.

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