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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds genuine context beyond that: every figure ships with its source, and unverified figures are flagged as not yet checked against the official text. It doesn't discuss freshness/refresh behavior, but it meaningfully extends the 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?

Two dense sentences with the resource content front-loaded and the routing rule after it; no filler. The first sentence is long and slightly run-on, which trims it from a perfect score.

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?

An output schema exists, so return values need not be described, and the description covers what is queried and when. For a single-optional-parameter reference lookup with rich annotations, the definition leaves nothing an agent needs in order to call it correctly.

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 an enum, so a baseline of 3 applies. The description earns above that by unpacking what each category actually contains (sacred-month vs ordinary diya, latest month and annual averages, 1395 = 100 base), which is real meaning beyond the bare enum tokens.

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 ('look up') and resource ('official figures'), then enumerates the exact categories returned (diya, gold-coin prices, CPI, court fees). It explicitly contrasts itself with the calculate_* siblings, so an agent can distinguish it without opening a 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?

Gives an explicit when-to-use rule ('when the question is the figure itself') with a concrete example query, and an explicit alternative ('to apply a figure to a case, use the matching calculate_* tool'). The routing decision is fully specified.

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