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

There are no annotations, so the description carries the full burden. It does disclose important operational facts — auth mode is paid and pricing is per call — plus the round-trip behavior of each direction. It says nothing about error handling, mixed-content input, or rate limits, leaving meaningful behavioral gaps for a no-annotation tool.

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 payload is a metadata dump: origin URL, hostname, brand, aliases, family key, endpoint, and a Source description that verbatim duplicates the Summary. Keywords and use cases are also repeated in near-identical form. The actual functional content is buried well after six lines of registry bookkeeping, and every sentence does not earn its place.

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 two-parameter, no-output-schema tool, the conversion semantics for `direction` are complete. The `text` parameter and any failure modes remain undocumented, and no output format is described, so an agent still has to guess at input handling — adequate but with clear gaps.

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 description coverage is 0%, so the description must compensate. It thoroughly explains `direction` with worked examples for both enum values, but the required `text` parameter is never described — its expected shape, whether it accepts non-digit characters, or handling of mixed scripts is left entirely to inference.

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 Summary states a specific verb and resource — 'Convert digits between Persian/Arabic-Indic and ASCII' — and pins it with concrete examples (1405 → ۱۴۰۵, ۱۴۰۵ → 1405), which cleanly separates it from generic text tools in the sibling list. It does not explicitly differentiate itself from close siblings like persian_normalize or script_detect, so it stops short of a 5.

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?

Three 'Use case' lines give contextual scenarios (Persian form filling, DB columns, script detection), which implies when to reach for it. However there are no exclusions or named alternatives, and the third use case ('detect which numeral script a number uses') overlaps with the sibling script_detect, which is potentially misleading rather than guiding.

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