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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered; the description still adds real value with result ordering, workspace scoping, and the forward-compat semantics of 'source' (only 'orglines' today, other values return nothing). Pagination behavior for 'limit' and the response shape are not disclosed, which keeps it off a 5.

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 compact sentences, front-loaded with the core action and scope before the per-parameter notes. Every clause carries distinct information: ordering, read-only nature, date bounds, and the source compatibility caveat.

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 four-parameter read-only list tool with strong annotations and no output schema, the definition covers scope, ordering, date filtering, and the enum caveat. The remaining gap is the undocumented 'limit' parameter and whether results page, which matters for a list endpoint but is a narrow 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 description coverage is 0%, so the description must carry parameter meaning — and it does for 'from'/'to' (ISO YYYY-MM-DD, bounding the range) and 'source' (default and no-match behavior). It says nothing about 'limit' (1-100), so one of four parameters remains undocumented in both places, holding this to a baseline-plus score.

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?

Names a specific verb and resource ('List the caller's calendar events'), scopes it ('from their active workspace'), and states ordering ('soonest first'). 'Read-only' plus the list framing separates it cleanly from create_events/update_events/delete_events 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?

Usage is implied rather than prescribed: an agent can infer this is the retrieval path for events, and the source caveat tells it that any non-'orglines' value yields an empty result. There is no explicit when-to-use/when-not guidance and no named alternative for other listing needs.

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