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

Annotations already declare read-only/idempotent/non-destructive, and the description adds substantial non-obvious behavior: no pagination, oldest-first ordering, a hard 5000-row cap with silent truncation, and that results carry no cost figure. These are exactly the runtime traits an agent needs beyond the safety hints.

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-loads the core purpose and the critical scoping warning; the long parenthetical source list is informative rather than filler. Dense but every clause carries signal, so only marginally verbose.

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 compensates by disclosing the result cap, row ordering, and the absence of cost figures, and by noting the underlying REST endpoint. It does not describe the returned event fields, but the coverage is strong for a read-only timeline query.

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 semantics the schema lacks: it explains that start_date/end_date are effectively mandatory for correctness rather than optional filters. That elevates it above the schema-only baseline.

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 (query) and resource (business-event timeline) and enumerates the concrete event sources (GitHub, PagerDuty, Jira, Stripe, etc.) so it is unmistakably distinct from sibling cost/usage tools like query_costs and query_usage. It also clarifies the resource is 'the same events overlaid on the Cost/Event Explorer charts'.

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?

Gives a clear directive — 'Always scope with start_date/end_date' — plus the reason (no pagination, 5000-row cap, silent truncation on long histories). It does not name an explicit alternative sibling (e.g. when to prefer query_costs), so it stops short of full when/when-not routing.

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