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

Annotations already declare the read-only/idempotent, closed-world profile, so the bar is lower, yet the description still adds real behavior: the business-timezone interpretation of 'today', the 30-day ceiling, newest-first ordering, and the followUpsOnly filtering effect. It stops short of noting pagination/truncation behavior against maxItems, which is the only meaningful gap.

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 opening sentence front-loads purpose, followed by concrete user-intent phrasings, return shape, and parameter guidance in a compact flow with no filler. It is longer than the minimum but nearly every clause carries routing or parameter information; a tighter phrasing of the return summary would earn a 5.

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 an output schema present, the description is not obliged to enumerate return fields, yet it still previews the totals and per-conversation entries, so the agent knows what to expect. Combined with the usage and parameter guidance, nothing needed to select or call the tool correctly 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 already 100%, so baseline would be 3, but the description adds semantics the schema does not: 'today counts as day 1, in the business's timezone' and the mutual-exclusivity between lastDays and startDate/endDate. It also translates followUpsOnly into an intent ('who do I need to call back?'), though maxItems is left unaddressed.

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 a specific verb and resource ('Summarises what happened on the connected Nexwin account over a period') and grounds it in real user questions ('what's happened the last two days?', 'anything I need to follow up?'). It clearly distinguishes itself from get_call_chat_detail by naming it as the route to full transcripts, and from get_account_usage_summary by scoping to calls/chats activity.

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 states exactly when to use the tool, when to set followUpsOnly ('who do I need to call back?'), and explicitly names the alternative for a related need (get_call_chat_detail for a full transcript). The date-window rule (lastDays OR startDate/endDate, 30 days max) removes the main invocation ambiguity.

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