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

Annotations declare readOnlyHint=false and idempotentHint=true; the description explains exactly why — it mutates state by adding the creator to the campaign and spending credits, and repeat reveals are free, which is consistent with idempotency. Credit costs and side effects are disclosed beyond the structured fields.

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 sentences, front-loaded with the return value, then the side effect and pricing, then the prerequisite for send_email. Every clause carries decision-relevant information.

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, and the description still names what comes back (the email address). With two fully documented params and annotations covering the safety profile, nothing an agent needs is missing.

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 description coverage is 100% and both parameters are documented with their sources (search_creators, list_campaigns/create_campaign). The description only implies campaign scoping ('in this campaign'), so the baseline 3 applies.

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 ('Returns the creator's email address') plus the scope ('in this campaign'), and distinguishes itself from send_email by declaring it a prerequisite. The 'adding the creator to the campaign first if needed' clause implicitly separates it from unlock_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?

Gives explicit conditions: use before send_email, use when you need the email, and reveals the cost trade-off (0.5 credits to add/unlock first time, 0.2 to reveal first time, free thereafter in any campaign). The agent knows both when to call it and what it will cost.

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