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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds substantial context beyond them: the 15-minute scan granularity, the ranking heuristic (maximize people in working hours, avoid night), DST-correct offsets per date, the return shape (up to 5 slots with local start and end per person), and the explicit no-feasible-time message. This is exactly the behavioral disclosure an agent needs.

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?

Four tight sentences, front-loaded with the usage trigger, then mechanics, then return behavior, then defaults. No sentence is redundant and no padding or hedging appears.

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 6-parameter read-only tool with no output schema, the description covers input defaults, ranking logic, return payload, and the empty-result case. Nothing an agent needs in order to call it correctly or interpret results is missing.

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 schema already documents every parameter and its default. The description restates the defaults (9–17 working hours, 60 minutes, date today in the first place) and the count of returned slots, but adds little meaning beyond what the schema fields already state, so the baseline 3 applies.

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 ('scheduling a call across several places') and immediately conveys the function as cross-time-zone slot finding, which is distinct from the sibling conversion tools (meridian_convert_time, meridian_now, meridian_zone_info). An agent can select it without opening the schema.

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?

Opens with an explicit when-to-use trigger ('Use when you need to schedule a call across several places'), giving clear invocation context. It does not name alternatives or exclusion conditions (e.g., use meridian_convert_time when you only need a point-in-time conversion), so it stops short of a 5.

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