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

Annotations already declare the safe read-only profile, and the description adds real behavioral context beyond them: recurring events are expanded into per-date occurrences (a non-obvious expansion rule) and results are ordered newest first. It stops short of noting pagination or the 250 cap behavior, which lives only in the schema.

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, front-loaded with the core verb and ordering, then the recurring-expansion caveat, then defaults. No filler; each sentence carries distinct information.

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 list tool with full schema coverage and annotations covering safety, the description is nearly complete; its most valuable non-obvious fact (recurring expansion) is captured. Minor gap: no note on return shape or how limit/pagination interact, but with no output schema that is a small omission.

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 schema already documents limit, mailbox, timeMin/timeMax and calendarId. The description restates the default window and primary calendar rather than adding syntax or format detail. Baseline 3 applies when the schema does the heavy lifting.

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+resource ('List events') plus scope ('in a time window') and ordering ('newest first'), so the agent knows exactly what it returns. It does not differentiate itself from the sibling search_google_calendar_events, which is the one ambiguity that keeps it from a 5.

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?

Usage is implied by the default window ('next 7 days of the primary calendar'), but there is no explicit when-to-use guidance and no mention of search_google_calendar_events as the alternative for filtered/query-based lookups. Adequate but leaves routing to inference.

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