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

Annotations already carry the core safety signals: readOnlyHint=false, idempotentHint=true, destructiveHint=false. The description adds useful context that the saved list is the pool campaigns draw from, but it doesn't describe effects like duplicate handling, persistence details, or return behavior. There is 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?

One sentence with no filler; the core action and the larger purpose (campaign shortlists) are both included. It is appropriately front-loaded and compact.

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 simple one-parameter, idempotent mutation with no output schema, the description covers what the tool does and why the saved list matters. It doesn't state the return value, but annotations covering idempotence and non-destructiveness make that a minor omission.

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?

The description doesn't explicitly explain creator_id's format or meaning beyond the schema, and schema description coverage is 0%. However, with a single obvious parameter named creator_id and the description saying 'Add a creator', the mapping is clear enough to be minimally viable, though the description adds little beyond 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 uses a specific verb ('Add') plus a resource ('a creator to your saved list') and adds context that the saved list is the source for campaign shortlists. This makes the tool's function explicit and distinguishes it from siblings like unsave_creator.

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 description clearly indicates when to use the tool: when a creator should be placed on the saved list that campaigns draw from. It doesn't explicitly mention alternatives or exclusions, such as using unsave_creator for removal, so it provides clear context without full when-not guidance.

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