Add Participant

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

Beyond the annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=false), the description discloses real behavior: existing participants are returned unchanged, the call bypasses the public application review flow, and the enrollment status outcome depends on isAffiliate/referredBy. These are consequential side-effect details the annotations cannot express.

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 purpose and the key 'existing participants returned unchanged' behavior, then the affiliate logic. The conditional rules are non-obvious and earn their space, though the description is dense and could be tightened.

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?

With an output schema present, return values need not be explained, and annotations cover the safety profile. The description thoroughly covers the affiliate/referral enrollment logic and targeting default, but omits auth/permission needs and most secondary parameter meaning for an 11-param mutation tool.

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 only 18%, so the description must carry the load, and it does add genuine meaning for the trickiest params (isAffiliate outcomes, referredBy interaction, campaignId default). But it leaves the majority of the 11 params (fingerprint, ipAddress, mobileInstanceId, referralStatus, metadata, name fields) undocumented, so it only partially compensates.

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+resource: 'Add or fetch a participant by email.' The add-or-fetch semantics is distinctive and distinguishes it functionally from get_participant (fetch only) and update_participant, though no sibling is named explicitly, keeping it from a 5.

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?

Provides clear context of use — 'trusted direct enrollment and bypasses the public application review flow for affiliates' — and conditions for the affiliate/referral flags. However it never names an alternative tool or states when not to use this one versus get_participant/update_participant, so it stops short of explicit routing.

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