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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds meaningful behavioral details beyond that: weekends are treated as outside working hours, and it also prints the requesting user's own zone from the shared business profile.

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 dense, front-loaded sentences cover the purpose and key behavioral nuances without repetition or filler. Every clause adds information the agent needs.

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 parameters and safety fully covered by annotations, the description sufficiently explains the return content: contact zones, current local time, working hours, in-hours status, weekend policy, and the caller's zone. Nothing critical is missing for correct invocation.

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?

There are zero parameters and schema description coverage is complete at 100%, so the baseline is 4. The description correctly focuses on output semantics rather than parameter documentation, and no parameters need clarification.

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 ('List'), the resource ('saved contacts'), and the distinctive output: zone, local time, working hours, and in-hours status. This cleanly separates it from sibling tools like contacts_set and the generic time utilities.

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 makes clear the tool is for listing saved contacts enriched with scheduling-relevant information年代中期 local time and working hours. It does not explicitly name alternatives or exclusions, but the use case is strongly implied and distinguishes it from other siblings.

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