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

With annotations already declaring readOnlyHint=false, idempotentHint=false and destructiveHint=false, the description still adds meaningful behavior: it creates *or* fetches a participant, performs trusted direct enrollment that skips review, and resolves the target campaign from `GROWSURF_CAMPAIGN_ID` when not passed. It omits token lifetime/scope, what happens on repeat calls, and any auth/permission requirements for the mutation side.

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 short sentences, with the core action front-loaded before the trust/flow caveat and the campaign-resolution detail. Minor filler ('via GrowSurf REST') could be cut, but nothing is bloated or buried.

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?

An output schema exists, so return values needn't be explained, and the description does cover the dual create-or-fetch nature and trusted-enrollment semantics. For a 12-parameter, nested-object tool it still leaves too much unaddressed: no permissions/auth needs, no note on what fetching an existing participant means for the other parameters, and no token characteristics.

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 only 25% across 12 parameters, so the description carries the compensation burden and largely fails to meet it. Its only parameter-relevant statements ('targets campaignId', 'trusted direct enrollment' for isAffiliate) restate what the schema's own `campaignId` and `isAffiliate` descriptions already say, leaving metadata, referralStatus, mobileInstanceId, ipAddress, fingerprint and the rest undocumented in both places.

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 names a specific compound operation: create/fetch a participant, then mint a participant-scoped mobile SDK token 'via GrowSurf REST'. That is far more specific than the title alone and distinguishes it from plain participant tools. It stops short of explicitly contrasting itself with the closest sibling, growsurf_participant_auth_hash, so an agent still has to infer which token mechanism applies.

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 gives a real usage condition — participant creation here is 'trusted direct enrollment' that 'bypasses the public application review flow' — which tells the agent this is not the path for public applicants. However, it never names an alternative tool or states when to prefer growsurf_add_participant, growsurf_participant_auth_hash, or the public application flow; the routing is only implied.

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