Update Participant

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

The annotations carry only readOnlyHint=false and destructiveHint=true, and the description adds substantial behavioral context: partial-update behavior, 400 rejection of read-only fields (counters, isAffiliate, origin, fraud state), the affiliateStatus enrollment rules (APPROVED enrolls; SUSPENDED/BANNED require an existing affiliate), the REST limitation on removing affiliate enrollment, and notes never being shown to participants. No contradiction with the annotations exists.

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?

The description is long but logically front-loaded: core update behavior first, then rejection rules, affiliate caveats, notes privacy, and campaign targeting. Every sentence contributes information; the only mild redundancy is affiliateStatus detail that also appears in the schema, which is acceptable for a high-risk field.

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 13-parameter write operation with an output schema and nested objects, the description covers the critical behavioral context: identification keys, partial-update semantics, rejection behavior, affiliate constraints, and campaign targeting. Since an output schema exists, return values need not be described; the main remaining gap is parameter-level meaning for the undocumented fields.

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 31% (4 of 13 params documented), and the description meaningfully compensates for the riskiest semantics: it clarifies that only sent fields change, which fields get rejected, and how affiliateStatus behaves. But it adds little for the nine undocumented parameters (referredBy, vanityKeys, unsubscribed, metadata, firstName, lastName, participantId, participantEmail, referralStatus), so the compensation is incomplete for a tool with this many parameters.

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 opening clause 'Update a participant by GrowSurf participant ID or email' states a specific verb, resource, and the two identification methods. This cleanly separates it from siblings like growsurf_add_participant, growsurf_get_participant, and growsurf_bulk_delete_participants without needing to inspect 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?

The description gives strong contextual cues for correct invocation, namely partial-update semantics ('Only the fields you send are changed') and the campaign targeting rule ('Targets campaignId if you pass it, otherwise GROWSURF_CAMPAIGN_ID'). However, it never explicitly states when to prefer this tool over alternatives such as growsurf_add_participant or when updating is inappropriate, leaving the selection to inference from the tool name.

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