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

All annotations are false, so the description carries the behavioral burden. It discloses persistent saving, return of resolved zone and local time, replacement of same-name contacts, and the free limit of 5. It does not cover error cases or permission needs, but the key behaviors are present and non-contradictory.

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 sentences, each earning its place: core action, return behavior, and replacement caution plus limit. No fluff, front-loaded with the primary purpose.

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 simple save tool with no output schema and no helpful annotations, the description covers the essentials: what it does, what it returns, replacement behavior, and the free limit. Minor gaps around error handling and exact response structure are not necessary 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?

Schema coverage is 100%, with descriptions for all four parameters, so the baseline is 3. The description adds the notion of zone resolution and working hours, but it does not provide meaningful format or usage details beyond the schema. Marginal added value over the structured fields.

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 states a specific action and resource: 'Save one person's zone and working hours' with a clear purpose ('so later calls can name them'). It is immediately distinguishable from siblings like contacts_list (save vs. list) and the time-conversion tools.

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?

No explicit when-to-use or when-not-to-use guidance is given, and no alternative tools are mentioned. The purpose clause implies a use case, but the agent must infer when this tool is appropriate versus siblings like contacts_list or convert_time.

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