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

Annotations already declare read-only, idempotent, non-destructive, closed-world, so safety is covered; the description adds real value beyond that: result ordering, the fact that each event carries the collector's decision and reason, isolation from reports/Realtime/usage, and the dashboard prerequisite. It does not say what happens when no session is active (empty list vs. error) or whether results are bounded/paginated.

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 short sentences, purpose first, then the semantics of the returned data, then the human prerequisite. Every sentence carries information not present in the schema or annotations.

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 one-parameter read tool with annotations and no output schema, the description covers what is returned, ordering, isolation semantics and how a session comes to exist. The remaining gap is the empty/no-session case and result limits, which an agent would otherwise have to discover empirically.

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% and the single site_id parameter is already documented in the schema, including that names, slugs and domains resolve. The description adds no parameter-level meaning, 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?

The first clause names the exact resource and scope ('the events of the site's debug session') plus ordering ('newest first'), which no sibling tool covers — get_errors, get_realtime and get_timeseries are clearly different resources. An agent can select this without opening the schema.

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 gives a concrete use case ('check an installation or a new event actually arrives') and a prerequisite ('A person starts a session in the dashboard under Settings, Debug'). It also implicitly routes away from get_realtime by noting session events never reach Realtime, though it never states an explicit when-not condition.

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