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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior, so the description's main added value is the supported-year limitation ('currently 2026'), which tells the agent that other years will likely fail. It does not describe the shape or size of the returned mapping, but the important constraint is disclosed up front.

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?

A single sentence with zero filler; the resource and the critical year restriction are both front-loaded before any caveat.

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 one-parameter, read-only lookup with no output schema, the definition covers what the tool returns conceptually and which inputs are valid. The only gap is that the return structure of the calendar mapping is not hinted at, which matters slightly since no output schema exists.

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% and the schema already says 'Gregorian year e.g. 2026', so baseline would be 3. The description still earns credit by narrowing the accepted domain to a supported year (currently only 2026), which the schema does not express.

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 ('Get full Hijriah calendar mapping') and scopes it to a Masehi/Gregorian year. The word 'full' implies bulk/year-wide output, which implicitly distinguishes it from a single-date conversion, but the sibling hijriah_konversi is never named, so differentiation is left to inference.

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?

Usage is implied by the word 'full' — this is the year-wide mapping tool rather than a point conversion — but there is no explicit statement of when to prefer it over hijriah_konversi, and no guidance on fallback behavior for unsupported years beyond the parenthetical '(currently 2026)'.

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