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

Annotations already declare readOnly, idempotent, and non-destructive, so safety is covered. The description adds genuine behavioral context beyond them: the result ordering (newest activity first), the inclusion of archived and aged-out items, and the non-obvious quirk that the weekly Brief belongs to no stream and is therefore invisible to stream-filtered calls. It stops short of describing the response envelope beyond the next_cursor mention.

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?

Four sentences, zero filler. Purpose and scope come first, the sibling routing second, the mechanics third, and the edge-case caveat last — each sentence carries information an agent needs.

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 still covers scope, ordering, pagination, and an enum interaction quirk, which is most of what an agent needs. It could say slightly more about what a returned row looks like or whether next_cursor is null on the last page, but nothing essential is missing.

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%, so the baseline is 3, but the description adds real meaning beyond the field docs: it explains the cursor round-trip ('passing next_cursor back verbatim as cursor') and, more importantly, the cross-parameter interaction where a stream filter silently excludes type=brief. That interaction is not derivable from the schema alone.

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 states a specific verb and resource plus its scope: 'the full report ledger for a site, newest activity first: every report series it ever had, including archived subjects and cards that aged out of the dashboard.' It explicitly contrasts itself with the siblings list_opportunities and list_questions, so an agent can route without opening any 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?

It gives an explicit when-to-use framing ('This is the investigation and history view') and names the alternatives for the current-state case ('for what matters now, use list_opportunities and list_questions instead'). The final sentence adds a concrete exclusion rule for stream-filtered calls, which prevents a plausible misuse.

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