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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so safety is covered. The description adds the ordering guarantee ("oldest first"), which is genuinely behavioral information not present in the schema, but stops short of describing pagination flow across pages, filters interacting with ordering, or what an empty session yields.

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?

Two tight sentences, front-loaded with the action, followed by the interpretive gloss on what the returned events represent. No filler.

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 filtered, paginated read tool with complete schema coverage and full annotations, the definition is nearly sufficient. The only shortfall is that pagination behavior and the session-id dependency are left implicit.

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 100%, documenting id, the event type enum, the 1-100 limit defaulting to 100, and starting_after as a cursor. The description adds nothing beyond this, so the baseline of 3 applies.

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?

"List events for a session" gives a specific verb plus resource, and the follow-on sentence clarifies the semantics: a single person's ordered path through a flow. However, with close siblings like list_flow_events and get_flow_session present, the description never states how this differs (session-scoped vs flow-wide).

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?

The description implies the tool applies when you have a session id, but there is no explicit when-to-use, when-not, or mention of alternatives such as list_flow_events (all events for a flow) or get_flow_session (session summary). No prerequisite about sourcing the id from list_flow_sessions is given.

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