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

Annotations already declare readOnlyHint=true, and the description adds real context beyond that: AND-only filter semantics, offset/limit paging with next_offset, the null-completion indicator for open reminders, and the underlying POST endpoint. Return shape is only partially described, but it goes meaningfully beyond the annotation.

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?

Front-loaded with the purpose and scope, then paging, then field names. It is dense but nearly every clause carries information; the long field list is slightly list-heavy but still relevant.

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 five-parameter, nested-criteria search with no output schema, the description covers filtering semantics, paging and continuation, and the notion of open versus completed records. It stops short of sketching the result shape (e.g., that results contain reminder objects), but overall it is 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?

Schema coverage is 100%, so the baseline is 3; the description earns a step up by listing the practically useful field names (reminder_date, contact_id, priority_id, etc.) and clarifying that next_offset drives continuation. It does not add operator syntax detail, but it usefully concentrates which criteria fields matter.

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?

States a specific verb and resource (search reminders) and adds scope detail (linked to contacts, properties, listings; includes tasks). It is clearly distinct from rex_get_reminder or rex_create_reminder, though it never names the sibling alternatives 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?

Explains that criteria combine with AND and how paging works, and notes that open reminders have a null system_completed_time, which is useful context. It does not say when to use this search versus rex_get_reminder, nor does it state that rex_describe_search_fields should be consulted first (that hint lives only in the schema).

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