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

Annotations already mark the tool as read-only and idempotent, and the description adds valuable behavioral context beyond that: the ~180-day range limit, the fact that the Hebrew date advances after sunset, and the return contents (Hebrew date in English and Hebrew letters plus holidays/events). No contradiction with annotations.

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?

The description is compact and front-loaded with the core purpose, then uses clear arrow-style usage lines. Every sentence adds necessary operational detail without repetition or fluff.

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?

Despite having no output schema and six optional parameters, the description covers both conversion directions, input formats, the range cap, the sunset edge case, and the return payload. An agent has enough information to invoke the tool correctly in either mode.

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?

The input schema already covers 100% of parameter documentation, so the baseline is 3. The description adds meaning by grouping parameters into conversion directions, explaining the end_date range behavior, and clarifying the after_sunset effect, which goes beyond the schema's individual descriptions.

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?

Description states a specific verb and resource: 'Convert between Gregorian and Hebrew (Jewish) calendar dates.' It clearly distinguishes this tool from calendar-related siblings by emphasizing bidirectional date conversion rather than schedules, zmanim, or calendar listings.

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 gives explicit direction on when to use which parameters: 'Gregorian → Hebrew: pass gregorian_date' and 'Hebrew → Gregorian: pass hebrew_year, hebrew_month, hebrew_day.' It also explains when to set after_sunset. However, it does not explicitly name alternative sibling tools or state exclusions, so it stops short of full alternative routing.

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