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

The description goes far beyond the readOnly/idempotent annotations by explaining observation-time semantics, the occurred_at vs observed_at distinction, next_since-based polling, the historical backfill date, and the first-seen accrual behavior. This gives the agent critical behavioral context no annotation provides.

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 dense but purposeful: every clause adds either scope, field semantics, polling behavior, or filter options. It is longer than ideal, but for a tool with this many event varieties the detail is justified rather than filler.

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?

It covers the tool's scope, return fields, filter dimensions, polling mechanics, and backfill caveat, which is sufficient even without an output schema. The main gap is the ambiguous overlap between 'next_since' and the cursor-based paging mentioned in the schema.

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 43%, and the description compensates well for 'since', event_type, signal_family, and subject id/dfx_id semantics. However, it does not clarify 'until', 'limit', or the relationship between 'next_since' and the schema's 'cursor'/'next_cursor' pagination, leaving some parameters under-specified.

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 the exact resource ('RIA event tape'), the organizing dimension ('by OBSERVATION time'), and the concrete event types it covers, from advisor departures to roster exits. This clearly differentiates it from generic search tools and sibling RIA-specific tools without needing to name them.

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 explicit polling guidance ('poll with the next_since the answer returns') and explains the backfill cutoff behavior for since values before 2026-09-15. It does not explicitly state when not to use this tool or name an alternative, but the usage context is clear.

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