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

Annotations already cover readOnlyHint, idempotentHint and destructiveHint, so safety is handled externally. The description adds the genuine extra constraint that the event_id must resolve "in the same accessible account context," which hints at workspace scoping/auth requirements beyond the annotation set.

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 tight sentences: purpose + endpoint first, then the use condition, then constraints. Every clause carries information and nothing is repeated; the minor redundancy of "read-only" against the annotation is negligible.

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 read-only single-record fetch with no output schema, the description supplies endpoint, trigger condition and the account-context caveat, which is sufficient to call it correctly. It could note the return shape of the "full event detail," but the safety profile is already in annotations.

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 83%, so the schema already documents base_url, api_token, account_id, access_token and app_password. The description mentions event_id and account context in prose but adds no format, type or aliasing detail beyond the schema, 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 ("Fetches one time event by event_id") and pins the exact endpoint /events/{id}, making it unambiguous that this returns a single event rather than a collection. This cleanly separates it from list_events, list_filtered_events, get_events_summary and get_events_stats in the sibling set.

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?

"Use when you already have an event identifier and need full event detail" gives a clear positive trigger condition tied to having an ID. It stops short of naming explicit alternatives or when-not cases (e.g. bulk retrieval), so it is good but not fully routing guidance.

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