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

readOnlyHint=true already declares the safety profile, so the description earns credit by disclosing the payload contents (registration types, fields, sessions, counts, totals paid/due) that the agent would otherwise not know without an output schema. It stops short of noting auth scopes or error behavior.

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 action and result fields in one tight sentence, with no wasted preamble. The trailing 'Wild Apricot: GET /accounts/{accountId}/events/{eventId}' restates the operation and references an accountId that is not a parameter, adding minor noise.

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 no output schema, the description usefully enumerates the returned fields, which is the main gap a read tool would otherwise have. Only missing pieces are auth/prerequisite context and any behavior on a missing or invalid event_id.

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% for the single event_id parameter, so the schema already fully documents it; the description adds no syntax, format, or source-of-id guidance. Baseline 3 is appropriate when the schema carries the parameter meaning.

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 (Fetch) and resource (one event) and enumerates what 'details' means — description, registration types, fields, sessions, counts, totals — so it is clearly distinguishable from wildapricot_list_events. An agent knows exactly what it gets 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?

Usage is only implied: 'one event' suggests single-record lookup versus the sibling wildapricot_list_events, but the description never states when to use this instead of that tool, nor any prerequisite such as needing a known event_id first. Adequate but leaves routing to inference.

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