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

Goes well beyond the annotations: it discloses the credit cost (0.5 the first time per creator, free thereafter), the unlocking side effect, and the exclusion constraint that blocks the call. The idempotentHint is effectively explained by the repeat-add-is-free note, and no behavior contradicts readOnlyHint=false or destructiveHint=false.

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?

Front-loaded with the core action and scope, and every clause carries information (cost, alternative, precondition). The parenthetical about reveal_contact and the mid-sentence clause about unlocking make it slightly dense, but no sentence is wasted.

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?

Covers the mutation's cost, idempotent re-add behavior, side effect on the originating search, and the blocking condition, which is what an agent needs without an output schema. What the call returns is unspecified, but since no output schema exists this is a minor gap for a success/failure-style add operation.

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 baseline is 3, but the description adds real meaning beyond it: it explains that searchId marks the creator as added in that originating search, which is a side effect not obvious from 'The search the creator came from'. campaignId and creatorId gain no extra detail, keeping it below 5.

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 ('Adds a creator to a campaign') plus the stage ('at the outreach stage'), and explicitly contrasts with the sibling reveal_contact, which also adds a creator. An agent can distinguish it from reveal_contact and save_creator without opening the schema.

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?

Gives an explicit when-to-use rule ('build a shortlist before deciding whom to contact'), names the alternative (reveal_contact) and notes what it shares, and states a hard precondition: a creator excluded from the campaign cannot be added. Nothing about selection is left to inference.

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