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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower; the description adds real interpretive value by warning that the EVENT_MISSING_FROM_SOURCE change type is low confidence and not equivalent to cancellation. It says nothing about pagination behavior or result shape, but the caveat is genuine behavioral disclosure.

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 short sentences with the core semantics front-loaded, but the second clause ('for all events the user saved, is going to or marked interested') is grammatically tangled and takes a moment to parse correctly.

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, three-parameter tool with no output schema and no annotations gaps, the description covers what the tool returns at a high level and adds one important caveat. It is still thin on the since/limit parameters, so an agent can call it but not tune it confidently.

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 the parameter burden. It covers event_id's meaning and scope, but limit and since are entirely unexplained in both schema and description, leaving the agent to guess at the change-window and page-size semantics.

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 the resource ('detected changes with previous and current values') and its two scopes: a single event_id, or all events the user saved/is going to/interested in. That is specific enough to distinguish it from get_event_details, though the sibling differentiation is implicit rather than stated.

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 indicates which population of events is covered when event_id is omitted, which is a form of usage guidance. However, it never says when to prefer this over get_event_details or other siblings, and gives no when-not conditions.

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