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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so the safety profile needs no restating. The description goes beyond them usefully by disclosing concrete bounds — 90-day window, newest-first ordering, 50-event cap — plus that suppression status is included, but says nothing about what an empty result or a missing contact looks like.

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?

A single front-loaded sentence that enumerates the three returned data groups with their limits inline. Every clause carries information; there is no padding or restatement of the tool name.

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 and one required parameter, the description must carry the return-value burden, and it does characterize the three result groups and per-group bounds. It falls slightly short on response shape (how suppression is reported, whether automation history is bounded) but is otherwise sufficient to call the tool correctly.

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?

Only one parameter exists and the schema documents it fully at 100% coverage, so the schema does the heavy lifting. The phrase 'one contact' reinforces that the id must be a single contact identifier rather than a list, but adds no format or sourcing guidance beyond the schema.

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 description names a specific resource and a concrete scope: activity for a single contact, spanning email events, automations, and suppression status. It is clearly distinguishable from get_contact, which would return profile fields, though the description never says so explicitly.

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 only implied — an agent can infer this is the tool for 'what happened to this contact' once an id is known. There is no explicit when-to-use, when-not-to-use, or named alternative (e.g., campaign-level reporting tools or search_contacts) for cases outside a single-contact view.

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