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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description usefully shows the exact input→output transformation, but says nothing about what happens to non-digit characters, unsupported languages, or the return format.

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 front-loaded sentence with three illustrative examples; every element earns its place and nothing is padded.

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 two-parameter, no-output-schema, non-destructive utility, the description is nearly complete — the transformation is fully conveyed by example. It would be stronger with a note on handling of unsupported languages or non-digit text.

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 100% and both params are documented there, so the schema carries the burden and baseline is 3. The description adds only indirect value: the Hindi/Tamil/Urdu examples hint that the language parameter accepts names as well as codes, but no format or validation detail is provided beyond that.

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 description states a specific verb+resource: replacing ASCII digits 0-9 with a language's native digits, with concrete transformation examples. It is unambiguous about what it does, though it never distinguishes itself from overlapping siblings like transliterate or convert_script, which also transform text into other scripts.

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 narrow framing (digit-only replacement) and the examples, but the description never states when to pick this over transliterate or convert_script, which are the obvious alternatives for script-related work. No prerequisites or exclusions are given.

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